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Speech and Language Disorders
CHAPTER 155
Speech and Language Disorders Roger P. Rossi, DO Jason H. Kortte, MS, CCC-SLP Jeffrey B. Palmer, MD
Synonyms Aphasia: dysphasia Dysarthria: slurred speech Dysphonia: voice disturbance, change in voice, hoarseness, hypernasality, hyponasality
ICD-10 Codes R47.01 R49.0 R47.1 R47.81 I69.320
Aphasia Dysphonia Dysarthria and anarthria Other voice and resonance disorders Aphasia following cerebral infarction
Definitions A summary of the speech and language disorders described in this chapter is presented in Table 155.1. Aphasia is an acquired neurogenic impairment in language processing that can disrupt the modalities of language, including speaking, listening, reading, and writing. An individual with aphasia has sustained a primary insult to the brain in the area governing language, which most commonly is the left hemisphere. Aphasia occurs in 21% to 38% of cases of acute stroke and is associated with high morbidity and mortality as well as a heavy financial burden.1 Aphasia also results from conditions other than stroke, such as tumors and head trauma, and must be differentiated from motor or sensory dysfunction, psychiatric illness, confusion, or general intellectual impairment.2 In the United States, there are approximately 100,000 new cases of aphasia per year, the majority being women 65 years of age and older.3 Primary progressive aphasia is a term reserved for subtle, insidious, progressive language impairments associated with frontotemporal dementia. In primary progressive aphasia, there is relative preservation of other mental and cognitive functions for at least the first 2 years of the condition.4
Aphasia is classified into subtypes according to the ability to produce, understand, and repeat language.5 The ability to produce language is assessed in terms of fluency, defined as the rate of speech and the amount of effort required to produce speech. Each subtype of aphasia is associated with a specific profile of language ability and disability (Table 155.2). An individual with Wernicke aphasia produces fluent language, has impaired auditory comprehension, and has poor repetition skills. In contrast, Broca aphasia is characterized by nonfluent language, relatively intact auditory comprehension, and poor repetition skills. Motor speech disorders, which include apraxia and dysarthria, result from neurologic impairment affecting motor planning, neuromuscular control, or execution of speech.6 Apraxia of speech is a neurologic speech dysfunction characterized by an impaired ability to plan or program the sensorimotor commands required for directing volitional activities; it results in phonetically and prosodically normal speech and can occur without muscle weakness or impairments in receptive and expressive language. Apraxia of speech is a distinct disorder, although some of its symptoms can coexist in the presence of dysarthria and aphasia.2 Dysarthria, a group of motor speech disorders resulting from damage to the central or peripheral nervous system, affects 10% to 65% of individuals with acquired brain injury; the degree depends on the type, extent, and duration of injury.7 Dysarthria results from weakness, paralysis, or lack of coordination of the muscles affecting speech, resulting in an impairment of articulation, respiration, resonance, and phonation (voice production). Dysarthria can be divided into subtypes according to the speech characteristics and underlying pathophysiologic process. The various subtypes of dysarthria described include flaccid, spastic, ataxic, hypokinetic, hyperkinetic, and mixed. Dysarthric speech patterns resulting from neurogenic speech disorders should be differentiated from those resulting from structural problems (such as cleft palate or postlaryngectomy status) or psychogenic disorders.6 Anarthria is the extreme form of dysarthria in which an individual is entirely incapable of producing articulated speech. Individuals who present with dysarthria can often concomitantly exhibit dysphagia, or impaired swallowing, which can be expected due to the 895
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overlap of structures and functions used in speaking and swallowing.8 Dysphonia is faulty or abnormal phonation (voice production). Phonation is a complex phenomenon regulated by cranial and spinal nerves that innervate muscles and functions controlling speech and voice production. Although prevalence rates are not well established, dysphonia is common in any condition causing abnormal motion of the vocal cords or lack of coordination of breathing and speaking. These conditions often include brain stem stroke, Parkinson disease, amyotrophic lateral sclerosis, Guillain-Barré syndrome, myasthenia gravis, spastic dysphonia, and multiple sclerosis, among others,6 as well as secondary processes that alter the structure or function of the vocal cords, including vocal abuse (such as excessive talking, screaming, or smoking), trauma Table 155.1 Speech and Language Disorders Disorder
Definition
Aphasia
Language processing disturbance that can involve the expression of language, the comprehension of language, or both. Word-finding errors and difficulty in understanding language are classic indicators of aphasia.
Dysarthria
Group of motor speech disorders associated with muscle paralysis, weakness, or incoordination. Dysarthria is often manifested as slurred speech and does not involve language (receptive or expressive) processes.
Apraxia of speech
Motor speech disorder disrupting the motor programming of the volitional movements for speech. Individuals struggle to position articulators (i.e., lips, tongue) correctly. Apraxia can occur without muscle weakness or impairments in receptive and expressive language.
Dysphonia
Faulty or abnormal phonation (voice production). Vocal quality may sound hoarse, harsh, strained, or breathy.
(traumatic or prolonged intubation, arytenoid dislocation), status post–laryngeal surgery, and a variety of disorders (laryngeal cancer, reflux laryngitis).9 Dysphonia is distinguished from dysarthria in that dysphonia involves only the sound of the voice, whereas dysarthria involves the overall sound of speech, including resonance and articulation.
Symptoms Individuals with aphasia often complain of difficulty in the formulation or interpretation of language, specifically speaking, reading, writing, or understanding speech. They often report word-finding difficulties and can become frustrated by this. Some individuals, however, are unaware of their deficits. Individuals who solely have a motor speech disorder (e.g., dysarthria, dysphonia, or apraxia of speech) have no impairments in word finding and report no difficulties with reading, writing, or auditory comprehension but complain primarily of difficulty in producing intelligible speech. Aphasia develops most commonly after left hemispheric involvement even in people who are left-handed, whereas neglect, visuospatial impairments, and other cognitive syndromes are demonstrated more commonly with right hemispheric involvement.10
Physical Examination During the physical examination it is important to attend to the various elements of speech, language, and cognition including speech intelligibility, vocal quality, language content, fluency, and auditory comprehension. Deficits in these areas may warrant referral to a speech and language pathologist for further evaluation, testing, and recommendations for treatment. In the rehabilitation setting, the functional independence measure is widely used to assess various functional abilities including communication.11 Typical physical examination findings are described further on for the four main categories of speech and language disorders.
Table 155.2 Aphasia Syndromes Aphasia Type
Predicted Lesion Site
Comprehension
Fluency
Repetition
Broca
Inferior frontal gyrus; Brodmann area
Relatively intact
Nonfluent
Poor
Wernicke
Posterior superior temporal gyrus; Brodmann area
Impaired
Fluent
Poor
Conduction
Superior marginal gyrus and underlying white matter (arcuate fasciculus)
Relatively intact
Fluent
Poor
Transcortical motor
Anterior and superior to Broca area (watershed area)
Relatively intact
Nonfluent
Good or less impaired than spontaneous speech
Transcortical sensory
Posterior and inferior to Wernicke area (watershed area)
Impaired
Fluent
Good
Transcortical mixed (isolation)
Anterior and posterior association areas (watershed areas)
Impaired
Nonfluent
Less impaired than spontaneous speech
Anomic
Angular gyrus or anywhere in the left hemisphere
Relatively intact
Fluent
Good
Global
Left frontal, parietal, and temporal lobes
Impaired
Nonfluent
Poor
Modified from Helm-Estabrooks N, Albert ML. Manual of Aphasia and Aphasia Therapy, 2nd ed. Austin, TX: Pro-Ed; 2004.
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Aphasia Findings indicative of aphasia vary according to the location and size of the brain lesion (see Table 155.2). A characteristic sign of aphasia is difficulty in comprehending language (spoken, gestural, or written). This type of aphasia is generally termed Wernicke aphasia. Significant impairment can be characterized by difficulty in following simple commands; milder impairments may be obvious only during lengthy or complicated messages. Broca aphasia generally refers to a predominant dysfunction in verbal expression (difficulty in producing meaningful verbal output), which may be manifested as a total loss of language with the production of only jargon (multiple whole-word substitutions) or meaningless sounds. A person with less severe aphasia may be able to express basic wants and needs but have difficulty in expressing complex ideas in conversation. Paraphasias, or naming errors, constitute a classic symptom of aphasia. Phonemic paraphasias involve the substitution, addition, or omission of target sounds (phonemes). An individual may say “bable” for “table.” A semantic paraphasia occurs when an individual produces a word related in meaning to the target word (i.e., “fork” for “spoon”). The severity of impairment can vary for each modality of language (listening, reading, writing, recognition of numbers, and gesturing). Aphasia, then, is a primary disorder in the area of language, and is not a result of decreased auditory or visual perceptual skills, disordered thought processes, impaired motor programming, or weakness or incoordination of the speech musculature.1
Apraxia of Speech Apraxia, a disorder of higher motor cognition, is a frequent sequela of left hemispheric stroke. The most common sign of apraxia of speech is a struggle or effortful groping to speak. This struggle is a direct result of the difficulty in finding the correct position of the articulators (i.e., lips, tongue). Apraxic speech is often halting and may contain sound substitutions, consonant and vowel distortions, omissions, additions, and repetitions.6 The individual is aware of his or her speech errors and will attempt to self-correct them, with varying degrees of success. Severe forms of apraxia of speech may result in the inability to produce even simple words. Interestingly, most people with apraxia of speech can produce common everyday phrases or sayings (e.g., How are you? Have a nice day. Thank you.) without error. Nonverbal oral apraxia, which often coincides with apraxia of speech, is the inability to imitate or to follow commands to perform volitional movements with the mouth or tongue.6 Apraxia of speech is not caused by muscle weakness, decreased tone, or incoordination, nor is it the result of linguistic disturbances, as in aphasia. Sound-level errors in apraxia of speech are thought to result from difficulty with motor execution and not with the selection of phonemes found in aphasia.4 Apraxia of speech differs from dysarthria in that it is not a result of paresis or paralysis or the uncoordinated movements of articulatory muscles. Apraxia of speech is believed to
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reflect a disturbance in the planning and programming of movements used for speech.2 Errors in apraxia of speech are characteristically highly irregular, in contrast to dysarthric speech errors, which are typically consistent and predictable.
Dysarthria In dysarthria, speech is often characterized as being slurred, with the predominant dysfunction being distortions of speech sounds. Dysarthria may also be characterized by changes in the rate, volume, and rhythm of speech. Findings and degrees of involvement vary greatly, depending on the pathophysiologic mechanism affected. Table 155.3 presents an overview of the classification of dysarthria by type, anatomic localization of insult, and anticipated motor deficit.
Dysphonia Dysphonia is characterized by a reduction or alteration in vocal quality. Vocal quality can vary by degree of loudness, breathiness, hoarseness, or harshness. A common example of dysphonia is the hoarse vocal quality of individuals with laryngitis. In the extreme form, aphonia, the individual is incapable of producing any voice but may be able to produce voiceless speech (e.g., whispering). Dysphonia can significantly and adversely affect daily communication demands and result in decreased participation and activity, which may require behavioral, medical, and even surgical interventions. Certain conditions result in characteristic hypophonia of speech, or diminished speech loudness, as is commonly found in individuals with Parkinson disease.12
Functional Limitations Functional limitations depend on the nature and severity of the communication impairment. Severe deficits
Table 155.3 Classification of Dysarthria Type
Localization
Motor Deficit
Flaccid
Lower motor neuron
Weakness, hypotonia
Spastic
Bilateral upper motor neuron
Spasticity
Ataxia
Cerebellum
Incoordination; inaccurate range, timing, direction; slow rate
Hypokinetic
Extrapyramidal system (basal ganglia circuit)
Variable speed of repetitive movements, rigidity
Hyperkinetic
Extrapyramidal system
Involuntary movements
Mixed
Multiple motor systems (amyotrophic lateral sclerosis, multiple sclerosis)
Weakness, reduced rate and range of motion
Modified from Duffy JR. Motor Speech Disorders: Substrates, Differential Diagnosis, and Management, 2nd ed. St. Louis: Elsevier Mosby; 2005.
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can impair the ability to express basic daily needs or to understand simple directions. An individual may not be able to effectively interact with family members or friends, integrate into the community or work force, or even communicate with health care providers. Less severe deficits allow the individual to express and understand basic information but impair higher-level activities such as the expression and understanding of complex and lengthy information to meet vocational or social needs. Neurologic speech and language impairments can affect an individual’s ability to complete a range of daily life tasks, including the ability to read bills, newspapers, or environmental signs; to communicate using the telephone; and to participate effectively in conversations or school or employment activities. Speech and language impairments may result in frustration and can cause disruptions in personal relationships, community and religious participation, and vocational functioning. Individuals with aphasia often participate in fewer activities and report worse quality of life even when physical limitations, well-being, and social support are comparable to those of other individuals.13 Depression and anxiety can also be the result of the functional limitations and alteration of quality of the life that occur from such impairments.
Diagnostic Studies A speech and language pathologist or neuropsychologist often administers a variety of standardized instruments to evaluate and diagnose aphasia. The aim of these instruments is to identify the pattern of symptoms to classify the aphasic syndrome, which is critical for the development of individualized interventions. Similarly, there are targeted assessments for the diagnosis of dysarthria, dysphonia, and apraxia of speech. These detailed evaluations involve an oral-motor examination to identify the structure and function of oral, pharyngeal, and laryngeal musculature as well as speech characteristics, including rate, volume, and intelligibility. For determination of the etiology and pathophysiology of dysphonia, a referral to an otolaryngologist is warranted. Laryngoscopy is often necessary to evaluate both the structure and function of the larynx. Biopsy is indicated when a mass lesion is noted or suspected. Stroboscopic examination of the larynx, electroglottography, and acoustic voice analysis may reveal subtle abnormalities of vocal fold motion and resulting acoustic parameters.14 A voice spectrogram is sometimes useful for the quantitative assessment of vocal features. Advances in neuroimaging have also facilitated the identification of dysfunctional or damaged brain tissue responsible for resultant cognitive, speech, and language deficits and have contributed insight regarding the functional neuroanatomy of language. These advances have made it possible to characterize the cerebral organization that occurs in response to treatments administered and the conditions under which it occurs. Diffusion tensor imaging is a technique that allows visualization of cerebral white matter tracts and the potential changes associated with different treatments.15
Differential Diagnosis of Various Speech and Language Disorders APHASIA Confusion, delirium, or dementia Psychosis Apraxia of speech Dysarthria Neurogenic stuttering Echolalia Palilalia Selective mutism Depression APRAXIA OF SPEECH Dysarthria Aphasia Neurogenic stuttering DYSARTHRIA Apraxia of speech Aphasia Depression Abulia DYSPHONIA Acute and chronic laryngitis Laryngeal hyperfunction (abuse and misuse) Neurogenic disorders Psychogenic disorders (i.e., conversion dysphonia) Spasmodic dysphonia Structural disorders of the larynx (congenital, traumatic, arthritic, neoplastic)
Treatment Initial Treatment of speech and language disorders most often is performed by a speech and language pathologist. The ability to make gains and predict rehabilitation outcomes for individuals with impairments in speech and language is determined by a compilation of factors, such as duration postinjury, the site and size of the insult, the resultant severity of language impairment, as well as demographic factors such as age and educational level. Initial treatment depends on the nature and severity of the disorder and how it may affect function and quality-of-life measures. Therapeutic treatment plans for aphasia, apraxia of speech, dysarthria, and dysphonia vary greatly and must be individualized to the patient’s communication needs. Initial intervention often includes education of the patient and family about the communication impairment and compensatory strategies to facilitate communication.
Rehabilitation To maximize an individual’s communication skills, therapeutic interventions can offer specific strategies, exercises, and activities to regain functional communication abilities. The goals of these treatment strategies areas follows16: • Promote function and an effective communicative environment. • Provide compensatory strategies to communicate.
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• Provide education and counseling and relevant home programs for patent and family. • Reduce interfering behaviors.
Aphasia Approximately one-third of stroke survivors experience aphasia.17 Aphasia rehabilitation has been shown to be efficacious in those with stroke and other neurologic disorders resulting in aphasia.17 Intervention depends on the aphasia subtype and the individual’s specific strengths and weaknesses. Two general aphasia treatment categories include impairment-based and communication-based therapies. Impairment-based therapies aim at improving language functions and comprise practices in which the treatment stimulates specific listening, speaking, reading, and writing abilities. Communication-based approaches strive to enhance communication using alternative and comprehensive means and encourage various levels of intervention from family, friends, and caregivers consisting of everyday interactions and communicative challenges.18 General models of aphasia therapy involve stimulating intact language processes, facilitating maximal language and speech processes through hierarchical cues and prompts, and compensating for refractory deficits through alternative communication systems and partner-facilitated communication strategies.19 Common therapeutic activities may involve naming tasks that use hierarchical cueing techniques to improve language content and structure. Therapy may begin with the production of automatic speech tasks, such as stating numbers or the days of the week. More difficult tasks may involve individually naming objects and describing pictures using appropriate sentence and word forms. Errorless naming techniques and gestural training can promote recovery of word retrieval. The training of scripts can allow the individual to produce rehearsed sentences to meet needs in specific situations.20 Written expression can be targeted through functional activities such as writing and copying biographical information. Common activities to improve auditory comprehension include following simple or complex commands and answering spoken questions correctly. Therapy to improve reading comprehension may involve matching objects to written words, following written directions, or reading functional information (bills, medication labels, environmental signs). Activities that involve attention training, problem solving, and executive functioning skills have been shown to have a positive effect on verbal expression and auditory comprehension.21 Aphasia treatment also includes education. It is important to teach the individual with aphasia, his or her family, and health care providers compensatory strategies to facilitate communication. Environmental modification and partner-facilitated approaches can dramatically improve communication success.22,23 These behavioral interventions can include turning off the television to reduce distractions, speaking slowly, using simple language, offering a pen and paper, checking that one is understood, and paraphrasing. Effective wordfinding strategies include the use of circumlocutions such as descriptions, definitions, or even sound effects during communication breakdowns. Training of volunteers to serve as conversation partners by the “Supported Conversation for Adults with Aphasia” intervention has been shown to be effective.24
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The implementation of speech-generating devices as augmentative or alternative communication methods in speech therapy can be highly effective in restoring communication and linguistic abilities.25 Advances in computer technology and software have provided new therapeutic options in the treatment of aphasia. Computer programs allow clinicians to easily design activities, select stimulus items, present cues, and individualize reinforcements.26 Software programs can also be used to turn a computer into a speech output communication device, allowing people with severe aphasia to produce phrases and sentences of varying degrees of complexity.27,28 These programs often contain features such as word prediction and graphic cues to facilitate correct sentence structure. Video technology has allowed individuals with aphasia to follow prerecorded mouth movements with auditory and written cues to aid word retrieval for full sentences and even longer narratives.28 The growing popularity of user-friendly smart phones and mobile technologies has allowed individuals with aphasia and other speech and language disorders easy access to tools for enhancing communication including photos, videos, maps, prerecorded messages, and text support. The field of telerehabilitation has developed from these advances in technology to allow evaluation and treatment in the home environment. Recent changes in reimbursement for aphasia therapy have promoted the development of the “Life-Participation Approach to Aphasia.” This philosophy focuses on longterm life goals, incorporating “aphasia friendly” environments, use of communication partners, and identification of barriers to life participation.29
Dysarthria The rehabilitation of dysarthria is influenced by the specific subtype of dysarthria. Approaches to treatment include medical intervention, oral prosthetic devices, and behavioral management.6 People with dysarthria due to Parkinson disease may benefit from dopamine agonists to enhance motor and muscular activities. Palatal lifts and voice amplifiers are commonly used to improve intelligibility. A palatal lift and augmentation prosthesis has been used successfully in conjunction with behavioral management.30 Behavioral management of dysarthria involves muscle strengthening (e.g., lip closure, tongue protrusion, tongue elevation), improvement of breath support, and modification of posture. The individual with dysarthria learns to use compensatory techniques to decrease rate of speech, increase loudness, and “overarticulate.” As with aphasia, families and caregivers are educated in strategies to maximize communication. Treatment of severe dysarthria, anarthria, or aphasia may include the use of augmentative communication systems in which individuals use pictures, written words, alphabet or pictograph boards, or computer-based technologies to enhance communication. Some individuals can use computer systems that produce synthesized speech, offering a wide variety of communication topics and personalization to the individual needs.
Apraxia of Speech Treatment of apraxia of speech involves techniques to elicit accurate voluntary speech production. Various interventions incorporate multimodality cues, such as modeling mouth
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and lip movements, using verbal cues to describe accurate tongue and lip placement, and intoning words and sentences. Treatment approaches often incorporate the use of rate- and rhythm-control strategies.4 For severe cases, alternative communication strategies—such as writing, drawing, and communication books as well as computer technologies and software—are used to augment or replace speech.
Dysphonia Therapeutic management of dysphonia is targeted at the underlying disorder and the pathophysiologic process.31 Vocal hygiene education and proper voicing techniques can improve vocal quality for individuals with vocal nodules due to laryngeal hyperfunction (vocal abuse). Techniques to enhance vocal fold approximation are useful in individuals with vocal cord motion impairments. Laryngitis due to gastroesophageal reflux disease can be treated with a combination of voice therapy and a vigorous antireflux medication regimen including proton pump inhibitors.32 Hypophonia, a common speech dysfunction found in individuals with Parkinson disease, is characterized by decreased vocal loudness. An evidence-based protocoldriven voice therapy that has historically been used successfully with Parkinson disease individuals is the Lee Silverman Voice Treatment-LOUD (LSVT-LOUD), which focuses on factors such as neuroplasticity and the principles of motor learning. LSVT is a high-effort intensive treatment that aims at increasing vocal intensity through the increase in subglottal air pressure, or enhanced respiratory effort, for more effective cordal adduction and vibration.33
Procedures Injection of a paralyzed vocal cord with Gelfoam or Teflon can increase its mass, bringing the medial edge of the cord closer to the midline. This facilitates contact with the mobile contralateral vocal cord, thereby improving phonation. This solution may be only temporary, and at times surgery is needed. For cases of spasmodic dysphonia, the use of botulinum toxin and injection into the affected muscles can result in improved voice by correcting abnormal motion of the vocal folds.34
Technology There is increasing interest in the application of cortical stimulation as an adjuvant strategy in aphasia rehabilitation to enhance the recovery process. Noninvasive brain stimulation technologies such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been used in the treatment of aphasia. TMS is a procedure that uses magnetic fields to create electric currents in discrete brain areas; this can lead to increases or decreases in excitability of the affected cortex that last beyond the duration of the treatment itself. It has been reported to improve naming ability in chronic stroke patients with nonfluent aphasia since 2005 and possibly also phrase length during propositional speech. Studies have found duration of benefit from 2 months to 2 years after stimulation.35 Two main hypotheses of neurologic mechanisms have been considered. One hypothesis uses continuous cortical
stimulation to modify perilesional inhibition; the other uses intermittent cortical stimulation during speech therapy treatment to explore synaptic plasticity and long-term potentiation or depression.36 In the treatment of aphasia, the attempt is to inhibit the intact right hemisphere with the hypothesis that maladaptive activity in the right hemisphere limits language recovery in the impaired left hemisphere. This treatment essentially favors the reorganization of left hemispheric language networks.37 tDCS and the modulation of cortical excitability has shown promise for the augmentation of cognition and the enhancement of working memory and attention.35 With these neurostimulation techniques as with traditional therapies, there remains a large variability regarding stimulation parameters, including montage type, current stimulation, session duration, and number and frequency of treatment sessions. Constraint-induced aphasia therapy (CIAT) has been shown to be effective in the treatment of aphasia and is based on the principles of constraint induced movement therapy or learned nonuse of affected limbs after stroke. Aphasia patients often use nonverbal communication strategies such as gesturing or pantomiming. CIAT discourages these strategies and encourages only attempts at verbal expression to communicate needs.38 Melodic intonation therapy (MIT) is a treatment strategy that uses musical and rhythmic intonations of words and sentences to enhance brain plasticity. As the right brain is felt to have the ability to process musical stimuli and intonation, it is felt that dysfunctions in the left brain can undergo plastic changes by stimulation of functions of the intact right brain, such as music processing. The goal of MIT is to stimulate language recovery in the damaged left brain by the use of music with its melodic patterns, rhythms, and inflections.39
Surgery Surgery is sometimes needed for treatment of voice disorders. Individuals with mass lesions of the larynx may need surgical excision. For individuals with unilateral vocal cord paralysis, a surgical procedure can bring the paralyzed cord closer to the midline to achieve appropriate glottal closure. Implantation of a small device into the paralyzed hemilarynx, displacing the paralyzed cord toward the midline, can provide a lasting improvement in voice quality. Structural lesions (e.g., cleft palate) or functional disorders (e.g., weakness of the palatal elevators) may cause an inadequate seal of the velopharyngeal isthmus (the space between the soft palate and the pharyngeal walls); in either case, a surgical procedure to narrow the defect can sometimes provide improved speech quality.
Potential Disease Complications Individuals with severe speech and language disorders may suffer extreme psychosocial consequences, including isolation, unemployment, anxiety, depression, alienation, ostracism, and inability to fulfill essential family roles. Aphasia has been shown to be a risk factor for disability after stroke and plays a significant role in quality-of-life issues.10
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Potential Treatment Complications Injection or surgical implant of the larynx may result in complications including infection, hemorrhage, and local tissue trauma. Injected material may gradually be displaced and lose effectiveness, but this rarely leads to serious sequelae. After botulinum toxin injection, the vocal folds may become immobilized in the medial position, but this seldom results in airway obstruction. Adjacent spread of the botulinum toxin into surrounding muscles may worsen the voice disorder or produce dysphagia.40
References 1. Berthier ML. Poststroke aphasia: epidemiology, pathophysiology and treatment. Drugs Aging. 2005;22:163–182. 2. Hallowell B, Chapey R. Introduction to language intervention strategies in adult aphasia. In: Chapey R, ed. Language Intervention Strategies in Aphasia and Related Neurogenic Communication Disorders, 5th ed. Baltimore: Lippincott Williams & Wilkins; 2008:3–19. 3. Ellis C, Dismuke C, Edwards KK. Longitudinal trends in aphasia in the United States. NeuroRehabilitation. 2010;27:327–333. 4. Duffy J, McNeil MR. Primary progressive aphasia and apraxia of speech. In: Chapey R, ed. Language Intervention Strategies in Aphasia and Related Neurogenic Communication Disorders, 5th ed. Baltimore: Lippincott Williams & Wilkins; 2008:543–564. 5. Helm-Estabrooks N, Albert ML. Manual of Aphasia and Aphasia Therapy, 2nd ed. Austin, TX: Pro-Ed; 2004. 6. Duffy JR. Motor Speech Disorders: Substrates, Differential Diagnosis, and Management, 2nd ed. St. Louis: Elsevier Mosby; 2005. 7. Wang YT, Kent RD, Duffy JR, Thomas JE. Dysarthria associated with traumatic brain injury: speaking rate and emphatic stress. J Commun Dis. 2005;38:231–260. 8. Nishio M, Niimi S. Relationship between speech and swallowing disorders in patients with neuromuscular disease. Folia Phoniatr Logop. 2004;56:291–304. 9. Prater RJ, Swift RW. Manual of Voice Therapy. Austin, TX: Pro-Ed; 1984. 10. Jordan LC, Hillis AE. Aphasia and right hemisphere syndromes in stroke. Curr Neurol Neurosci Rep. 2005;5:458–464. 11. Linacre JM, Heinemann AW, Wright BD, et al. The structure and stability of the Functional Independence Measure. Arch Phys Med Rehabil. 1994;75:127–132. 12. Walton C, Conway E, Blackshaw H, Carding P. Unilateral vocal fold paralysis: a systematic review of speech-language pathology management. J Voice. 2016;16:30333–30332. 13. Hilari K. The impact of stroke: are people with aphasia different to those without? Disabil Rehabil. 2011;33:211–218. 14. Akyildiz SM, Ogut F, Varis A, et al. Impact of laryngeal findings on acoustic parameters of patients with laryngopharyngeal reflux. ORL J Otorhinolaryngol Relat Spec. 2012;74:215–219. 15. Nunnari D, Bonanno L, Bramanti P, Marino S. Diffusion tensor imaging and neuropsychologic assessment in aphasic stroke. J Stroke Cerebrovasc Dis. 2014;23(10):e477–e478. 16. Klein ER, Mancinelli JM. Past, present, and future considerations in acquired language disorders. In: Klein ER, Mancinelli JM, eds. Acquired Language Disorders: A Case Based Approach, 2nd ed. San Diego: Plural Publishing; 2014:199–207. 17. Brady MC, Kelly H, Godwin J, Enderby P, Campbell P. Speech and language therapy for aphasia following stroke. Cochrane Database Syst Rev. 2016;6:CD000425. 18. National Aphasia Association. Aphasia therapy guide; https://www. aphasia.org/aphasia-resources/aphasia-therapy-guide/ 19. Burns MS, Halper AS. Speech/Language Treatment of the Aphasias: An Integrated Clinical Approach. Rockville, MD: Aspen; 1988.
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20. Raymer AM, McHose B, Smith KG, et al. Contrasting effects of errorless naming treatment and gestural facilitation for word retrieval in aphasia. Neuropsychol Rehabil. 2012;22:235–266. 21. Helm-Estabrooks N. Treating attention to improve auditory comprehension deficits associated with aphasia. Perspect Neurophysiol Neurogenic Speech Lang Disord. 2011;21:64–71. 22. Lubinski R, Welland RJ. Normal aging and environmental effects on communication. Semin Speech Lang. 1997;18:107–125. 23. Hengst JA, Frame SR, Neuman-Stritzel T, et al. Using others’ words: conversational use of reported speech by individuals with aphasia and their communication partners. J Speech Lang Hear Res. 2005;48:137–156. 24. Kagan A, Black SE, Duchan FJ, et al. Training volunteers as conversational partners using “Supported Conversation for Adults with Aphasia” (SCA): a controlled trial. J Speech Lang Hear Res. 2001;44:624–638. 25. Lüke C. Impact of speech-generating devices on the language development of a child with childhood apraxia of speech: a case study. Disabil Rehabil Assist Technol. 2016;11:80–88. 26. Fink RB, Brecher A, Schwartz MF, et al. A computer-implemented protocol for treatment for naming disorders: evaluation of clinician-guided and partially guided instruction. Aphasiology. 2002;16:1061–1086. 27. McCall D, Virata T, Linbarger M, et al. Integrating technology and targeted treatment to improve narrative production in aphasia: a case study. Aphasiology. 2009;23:438–461. 28. Fridriksson J, Baker J, Whiteside J, et al. Treating visual speech perception to improve speech production in nonfluent aphasia. Stroke. 2009;40:853–858. 29. Silverman ME. Community: the key to building and extending engagement for individuals with aphasia. Semin Speech Lang. 2011;32:256–267. 30. Ono T, Hamamura M, Honda K, Nokubi T. Collaboration of a dentist and speech-language pathologist in the rehabilitation of a stroke patient with dysarthria: a case study. Gerodontology. 2005;22:116–119. 31. Chang JI, Bevans SE, Swartz SR. Evidence-based practice: management of hoarseness/dysphonia. Otolaryngol Clin North Am. 2012;45:1109–1126. 32. Park J, Shim M, Hwang Y, et al. Combination of voice therapy and antireflux therapy rapidly recovers voice-related symptoms in laryngopharyngeal reflux patients. Otolaryngol Head Neck Surg. 2012;146: 92–97. 33. Sale P, Castiglioni D, De Pandis MF, et al. The Lee Silverman Voice Treatment (LSVT®) speech therapy in progressive supranuclear palsy. Eur J Phys Rehabil Med. 2015;51(5):569–574. 34. Fulmer SL, Merati AL, Blumin JH. Efficacy of laryngeal botulinum toxin injection: comparison of two techniques. Laryngoscope. 2011;121(9):1924–1928. 35. Page SJ, Cunningham DA, Plow E, Blazak B. It takes two: noninvasive brain stimulation combined with neurorehabilitation. Arch Phys Med Rehabil. 2015;96(suppl 4):S89–S93. 36. Balossier A, Etard O, Descat C, Vivien D, Emery E. Epidural cortical stimulation as a treatment for poststroke aphasia: a systematic review of the literature and underlying neurophysiological mechanisms. Neurorehabil Neural Repair. 2016;30:120–130. 37. Turkeltaub PE. Brain stimulation and the role of the right hemisphere in aphasia recovery. Curr Neurol Neurosci Rep. 2015;15(11):72. 38. Woldag H, Voigt N, Bley M, Hummelsheim H. Constraint-induced aphasia therapy in the acute stage: what is the key factor for efficacy? A randomized controlled study. Neurorehabil Neural Repair. 2017;31(1):72–80. 39. Draper K. Music and Stroke Rehabilitation: A Narrative Synthesis of the Music-Based Treatments used to Rehabilitate Disorders of Speech and Language following Left-Hemispheric Stroke.Voices: A World Forum for Music Therapy, [S.l.], v. 16, n. 1, feb. 2016. ISSN 1504–1611. Available at: https://voices.no/index.php/voices/article/view/789/708. 40. Rossi RP, Strax TE, Di Rocco A. Severe dysphagia after botulinum toxin B injection to the lower limbs and lumbar paraspinal muscles. Am J Phys Med Rehabil. 2006;85:1011–1013.
Speech and Language Disorders Roger P. Rossi, DO Jason H. Kortte, MS, CCC-SLP Jeffrey B. Palmer, MD
Synonyms Aphasia: dysphasia Dysarthria: slurred speech Dysphonia: voice disturbance, change in voice, hoarseness, hypernasality, hyponasality
ICD-10 Codes R47.01 R49.0 R47.1 R47.81 I69.320
Aphasia Dysphonia Dysarthria and anarthria Other voice and resonance disorders Aphasia following cerebral infarction
Definitions A summary of the speech and language disorders described in this chapter is presented in Table 155.1. Aphasia is an acquired neurogenic impairment in language processing that can disrupt the modalities of language, including speaking, listening, reading, and writing. An individual with aphasia has sustained a primary insult to the brain in the area governing language, which most commonly is the left hemisphere. Aphasia occurs in 21% to 38% of cases of acute stroke and is associated with high morbidity and mortality as well as a heavy financial burden.1 Aphasia also results from conditions other than stroke, such as tumors and head trauma, and must be differentiated from motor or sensory dysfunction, psychiatric illness, confusion, or general intellectual impairment.2 In the United States, there are approximately 100,000 new cases of aphasia per year, the majority being women 65 years of age and older.3 Primary progressive aphasia is a term reserved for subtle, insidious, progressive language impairments associated with frontotemporal dementia. In primary progressive aphasia, there is relative preservation of other mental and cognitive functions for at least the first 2 years of the condition.4
Aphasia is classified into subtypes according to the ability to produce, understand, and repeat language.5 The ability to produce language is assessed in terms of fluency, defined as the rate of speech and the amount of effort required to produce speech. Each subtype of aphasia is associated with a specific profile of language ability and disability (Table 155.2). An individual with Wernicke aphasia produces fluent language, has impaired auditory comprehension, and has poor repetition skills. In contrast, Broca aphasia is characterized by nonfluent language, relatively intact auditory comprehension, and poor repetition skills. Motor speech disorders, which include apraxia and dysarthria, result from neurologic impairment affecting motor planning, neuromuscular control, or execution of speech.6 Apraxia of speech is a neurologic speech dysfunction characterized by an impaired ability to plan or program the sensorimotor commands required for directing volitional activities; it results in phonetically and prosodically normal speech and can occur without muscle weakness or impairments in receptive and expressive language. Apraxia of speech is a distinct disorder, although some of its symptoms can coexist in the presence of dysarthria and aphasia.2 Dysarthria, a group of motor speech disorders resulting from damage to the central or peripheral nervous system, affects 10% to 65% of individuals with acquired brain injury; the degree depends on the type, extent, and duration of injury.7 Dysarthria results from weakness, paralysis, or lack of coordination of the muscles affecting speech, resulting in an impairment of articulation, respiration, resonance, and phonation (voice production). Dysarthria can be divided into subtypes according to the speech characteristics and underlying pathophysiologic process. The various subtypes of dysarthria described include flaccid, spastic, ataxic, hypokinetic, hyperkinetic, and mixed. Dysarthric speech patterns resulting from neurogenic speech disorders should be differentiated from those resulting from structural problems (such as cleft palate or postlaryngectomy status) or psychogenic disorders.6 Anarthria is the extreme form of dysarthria in which an individual is entirely incapable of producing articulated speech. Individuals who present with dysarthria can often concomitantly exhibit dysphagia, or impaired swallowing, which can be expected due to the 895
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overlap of structures and functions used in speaking and swallowing.8 Dysphonia is faulty or abnormal phonation (voice production). Phonation is a complex phenomenon regulated by cranial and spinal nerves that innervate muscles and functions controlling speech and voice production. Although prevalence rates are not well established, dysphonia is common in any condition causing abnormal motion of the vocal cords or lack of coordination of breathing and speaking. These conditions often include brain stem stroke, Parkinson disease, amyotrophic lateral sclerosis, Guillain-Barré syndrome, myasthenia gravis, spastic dysphonia, and multiple sclerosis, among others,6 as well as secondary processes that alter the structure or function of the vocal cords, including vocal abuse (such as excessive talking, screaming, or smoking), trauma Table 155.1 Speech and Language Disorders Disorder
Definition
Aphasia
Language processing disturbance that can involve the expression of language, the comprehension of language, or both. Word-finding errors and difficulty in understanding language are classic indicators of aphasia.
Dysarthria
Group of motor speech disorders associated with muscle paralysis, weakness, or incoordination. Dysarthria is often manifested as slurred speech and does not involve language (receptive or expressive) processes.
Apraxia of speech
Motor speech disorder disrupting the motor programming of the volitional movements for speech. Individuals struggle to position articulators (i.e., lips, tongue) correctly. Apraxia can occur without muscle weakness or impairments in receptive and expressive language.
Dysphonia
Faulty or abnormal phonation (voice production). Vocal quality may sound hoarse, harsh, strained, or breathy.
(traumatic or prolonged intubation, arytenoid dislocation), status post–laryngeal surgery, and a variety of disorders (laryngeal cancer, reflux laryngitis).9 Dysphonia is distinguished from dysarthria in that dysphonia involves only the sound of the voice, whereas dysarthria involves the overall sound of speech, including resonance and articulation.
Symptoms Individuals with aphasia often complain of difficulty in the formulation or interpretation of language, specifically speaking, reading, writing, or understanding speech. They often report word-finding difficulties and can become frustrated by this. Some individuals, however, are unaware of their deficits. Individuals who solely have a motor speech disorder (e.g., dysarthria, dysphonia, or apraxia of speech) have no impairments in word finding and report no difficulties with reading, writing, or auditory comprehension but complain primarily of difficulty in producing intelligible speech. Aphasia develops most commonly after left hemispheric involvement even in people who are left-handed, whereas neglect, visuospatial impairments, and other cognitive syndromes are demonstrated more commonly with right hemispheric involvement.10
Physical Examination During the physical examination it is important to attend to the various elements of speech, language, and cognition including speech intelligibility, vocal quality, language content, fluency, and auditory comprehension. Deficits in these areas may warrant referral to a speech and language pathologist for further evaluation, testing, and recommendations for treatment. In the rehabilitation setting, the functional independence measure is widely used to assess various functional abilities including communication.11 Typical physical examination findings are described further on for the four main categories of speech and language disorders.
Table 155.2 Aphasia Syndromes Aphasia Type
Predicted Lesion Site
Comprehension
Fluency
Repetition
Broca
Inferior frontal gyrus; Brodmann area
Relatively intact
Nonfluent
Poor
Wernicke
Posterior superior temporal gyrus; Brodmann area
Impaired
Fluent
Poor
Conduction
Superior marginal gyrus and underlying white matter (arcuate fasciculus)
Relatively intact
Fluent
Poor
Transcortical motor
Anterior and superior to Broca area (watershed area)
Relatively intact
Nonfluent
Good or less impaired than spontaneous speech
Transcortical sensory
Posterior and inferior to Wernicke area (watershed area)
Impaired
Fluent
Good
Transcortical mixed (isolation)
Anterior and posterior association areas (watershed areas)
Impaired
Nonfluent
Less impaired than spontaneous speech
Anomic
Angular gyrus or anywhere in the left hemisphere
Relatively intact
Fluent
Good
Global
Left frontal, parietal, and temporal lobes
Impaired
Nonfluent
Poor
Modified from Helm-Estabrooks N, Albert ML. Manual of Aphasia and Aphasia Therapy, 2nd ed. Austin, TX: Pro-Ed; 2004.
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Aphasia Findings indicative of aphasia vary according to the location and size of the brain lesion (see Table 155.2). A characteristic sign of aphasia is difficulty in comprehending language (spoken, gestural, or written). This type of aphasia is generally termed Wernicke aphasia. Significant impairment can be characterized by difficulty in following simple commands; milder impairments may be obvious only during lengthy or complicated messages. Broca aphasia generally refers to a predominant dysfunction in verbal expression (difficulty in producing meaningful verbal output), which may be manifested as a total loss of language with the production of only jargon (multiple whole-word substitutions) or meaningless sounds. A person with less severe aphasia may be able to express basic wants and needs but have difficulty in expressing complex ideas in conversation. Paraphasias, or naming errors, constitute a classic symptom of aphasia. Phonemic paraphasias involve the substitution, addition, or omission of target sounds (phonemes). An individual may say “bable” for “table.” A semantic paraphasia occurs when an individual produces a word related in meaning to the target word (i.e., “fork” for “spoon”). The severity of impairment can vary for each modality of language (listening, reading, writing, recognition of numbers, and gesturing). Aphasia, then, is a primary disorder in the area of language, and is not a result of decreased auditory or visual perceptual skills, disordered thought processes, impaired motor programming, or weakness or incoordination of the speech musculature.1
Apraxia of Speech Apraxia, a disorder of higher motor cognition, is a frequent sequela of left hemispheric stroke. The most common sign of apraxia of speech is a struggle or effortful groping to speak. This struggle is a direct result of the difficulty in finding the correct position of the articulators (i.e., lips, tongue). Apraxic speech is often halting and may contain sound substitutions, consonant and vowel distortions, omissions, additions, and repetitions.6 The individual is aware of his or her speech errors and will attempt to self-correct them, with varying degrees of success. Severe forms of apraxia of speech may result in the inability to produce even simple words. Interestingly, most people with apraxia of speech can produce common everyday phrases or sayings (e.g., How are you? Have a nice day. Thank you.) without error. Nonverbal oral apraxia, which often coincides with apraxia of speech, is the inability to imitate or to follow commands to perform volitional movements with the mouth or tongue.6 Apraxia of speech is not caused by muscle weakness, decreased tone, or incoordination, nor is it the result of linguistic disturbances, as in aphasia. Sound-level errors in apraxia of speech are thought to result from difficulty with motor execution and not with the selection of phonemes found in aphasia.4 Apraxia of speech differs from dysarthria in that it is not a result of paresis or paralysis or the uncoordinated movements of articulatory muscles. Apraxia of speech is believed to
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reflect a disturbance in the planning and programming of movements used for speech.2 Errors in apraxia of speech are characteristically highly irregular, in contrast to dysarthric speech errors, which are typically consistent and predictable.
Dysarthria In dysarthria, speech is often characterized as being slurred, with the predominant dysfunction being distortions of speech sounds. Dysarthria may also be characterized by changes in the rate, volume, and rhythm of speech. Findings and degrees of involvement vary greatly, depending on the pathophysiologic mechanism affected. Table 155.3 presents an overview of the classification of dysarthria by type, anatomic localization of insult, and anticipated motor deficit.
Dysphonia Dysphonia is characterized by a reduction or alteration in vocal quality. Vocal quality can vary by degree of loudness, breathiness, hoarseness, or harshness. A common example of dysphonia is the hoarse vocal quality of individuals with laryngitis. In the extreme form, aphonia, the individual is incapable of producing any voice but may be able to produce voiceless speech (e.g., whispering). Dysphonia can significantly and adversely affect daily communication demands and result in decreased participation and activity, which may require behavioral, medical, and even surgical interventions. Certain conditions result in characteristic hypophonia of speech, or diminished speech loudness, as is commonly found in individuals with Parkinson disease.12
Functional Limitations Functional limitations depend on the nature and severity of the communication impairment. Severe deficits
Table 155.3 Classification of Dysarthria Type
Localization
Motor Deficit
Flaccid
Lower motor neuron
Weakness, hypotonia
Spastic
Bilateral upper motor neuron
Spasticity
Ataxia
Cerebellum
Incoordination; inaccurate range, timing, direction; slow rate
Hypokinetic
Extrapyramidal system (basal ganglia circuit)
Variable speed of repetitive movements, rigidity
Hyperkinetic
Extrapyramidal system
Involuntary movements
Mixed
Multiple motor systems (amyotrophic lateral sclerosis, multiple sclerosis)
Weakness, reduced rate and range of motion
Modified from Duffy JR. Motor Speech Disorders: Substrates, Differential Diagnosis, and Management, 2nd ed. St. Louis: Elsevier Mosby; 2005.
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can impair the ability to express basic daily needs or to understand simple directions. An individual may not be able to effectively interact with family members or friends, integrate into the community or work force, or even communicate with health care providers. Less severe deficits allow the individual to express and understand basic information but impair higher-level activities such as the expression and understanding of complex and lengthy information to meet vocational or social needs. Neurologic speech and language impairments can affect an individual’s ability to complete a range of daily life tasks, including the ability to read bills, newspapers, or environmental signs; to communicate using the telephone; and to participate effectively in conversations or school or employment activities. Speech and language impairments may result in frustration and can cause disruptions in personal relationships, community and religious participation, and vocational functioning. Individuals with aphasia often participate in fewer activities and report worse quality of life even when physical limitations, well-being, and social support are comparable to those of other individuals.13 Depression and anxiety can also be the result of the functional limitations and alteration of quality of the life that occur from such impairments.
Diagnostic Studies A speech and language pathologist or neuropsychologist often administers a variety of standardized instruments to evaluate and diagnose aphasia. The aim of these instruments is to identify the pattern of symptoms to classify the aphasic syndrome, which is critical for the development of individualized interventions. Similarly, there are targeted assessments for the diagnosis of dysarthria, dysphonia, and apraxia of speech. These detailed evaluations involve an oral-motor examination to identify the structure and function of oral, pharyngeal, and laryngeal musculature as well as speech characteristics, including rate, volume, and intelligibility. For determination of the etiology and pathophysiology of dysphonia, a referral to an otolaryngologist is warranted. Laryngoscopy is often necessary to evaluate both the structure and function of the larynx. Biopsy is indicated when a mass lesion is noted or suspected. Stroboscopic examination of the larynx, electroglottography, and acoustic voice analysis may reveal subtle abnormalities of vocal fold motion and resulting acoustic parameters.14 A voice spectrogram is sometimes useful for the quantitative assessment of vocal features. Advances in neuroimaging have also facilitated the identification of dysfunctional or damaged brain tissue responsible for resultant cognitive, speech, and language deficits and have contributed insight regarding the functional neuroanatomy of language. These advances have made it possible to characterize the cerebral organization that occurs in response to treatments administered and the conditions under which it occurs. Diffusion tensor imaging is a technique that allows visualization of cerebral white matter tracts and the potential changes associated with different treatments.15
Differential Diagnosis of Various Speech and Language Disorders APHASIA Confusion, delirium, or dementia Psychosis Apraxia of speech Dysarthria Neurogenic stuttering Echolalia Palilalia Selective mutism Depression APRAXIA OF SPEECH Dysarthria Aphasia Neurogenic stuttering DYSARTHRIA Apraxia of speech Aphasia Depression Abulia DYSPHONIA Acute and chronic laryngitis Laryngeal hyperfunction (abuse and misuse) Neurogenic disorders Psychogenic disorders (i.e., conversion dysphonia) Spasmodic dysphonia Structural disorders of the larynx (congenital, traumatic, arthritic, neoplastic)
Treatment Initial Treatment of speech and language disorders most often is performed by a speech and language pathologist. The ability to make gains and predict rehabilitation outcomes for individuals with impairments in speech and language is determined by a compilation of factors, such as duration postinjury, the site and size of the insult, the resultant severity of language impairment, as well as demographic factors such as age and educational level. Initial treatment depends on the nature and severity of the disorder and how it may affect function and quality-of-life measures. Therapeutic treatment plans for aphasia, apraxia of speech, dysarthria, and dysphonia vary greatly and must be individualized to the patient’s communication needs. Initial intervention often includes education of the patient and family about the communication impairment and compensatory strategies to facilitate communication.
Rehabilitation To maximize an individual’s communication skills, therapeutic interventions can offer specific strategies, exercises, and activities to regain functional communication abilities. The goals of these treatment strategies areas follows16: • Promote function and an effective communicative environment. • Provide compensatory strategies to communicate.
CHAPTER 155 Speech and Language Disorders
• Provide education and counseling and relevant home programs for patent and family. • Reduce interfering behaviors.
Aphasia Approximately one-third of stroke survivors experience aphasia.17 Aphasia rehabilitation has been shown to be efficacious in those with stroke and other neurologic disorders resulting in aphasia.17 Intervention depends on the aphasia subtype and the individual’s specific strengths and weaknesses. Two general aphasia treatment categories include impairment-based and communication-based therapies. Impairment-based therapies aim at improving language functions and comprise practices in which the treatment stimulates specific listening, speaking, reading, and writing abilities. Communication-based approaches strive to enhance communication using alternative and comprehensive means and encourage various levels of intervention from family, friends, and caregivers consisting of everyday interactions and communicative challenges.18 General models of aphasia therapy involve stimulating intact language processes, facilitating maximal language and speech processes through hierarchical cues and prompts, and compensating for refractory deficits through alternative communication systems and partner-facilitated communication strategies.19 Common therapeutic activities may involve naming tasks that use hierarchical cueing techniques to improve language content and structure. Therapy may begin with the production of automatic speech tasks, such as stating numbers or the days of the week. More difficult tasks may involve individually naming objects and describing pictures using appropriate sentence and word forms. Errorless naming techniques and gestural training can promote recovery of word retrieval. The training of scripts can allow the individual to produce rehearsed sentences to meet needs in specific situations.20 Written expression can be targeted through functional activities such as writing and copying biographical information. Common activities to improve auditory comprehension include following simple or complex commands and answering spoken questions correctly. Therapy to improve reading comprehension may involve matching objects to written words, following written directions, or reading functional information (bills, medication labels, environmental signs). Activities that involve attention training, problem solving, and executive functioning skills have been shown to have a positive effect on verbal expression and auditory comprehension.21 Aphasia treatment also includes education. It is important to teach the individual with aphasia, his or her family, and health care providers compensatory strategies to facilitate communication. Environmental modification and partner-facilitated approaches can dramatically improve communication success.22,23 These behavioral interventions can include turning off the television to reduce distractions, speaking slowly, using simple language, offering a pen and paper, checking that one is understood, and paraphrasing. Effective wordfinding strategies include the use of circumlocutions such as descriptions, definitions, or even sound effects during communication breakdowns. Training of volunteers to serve as conversation partners by the “Supported Conversation for Adults with Aphasia” intervention has been shown to be effective.24
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The implementation of speech-generating devices as augmentative or alternative communication methods in speech therapy can be highly effective in restoring communication and linguistic abilities.25 Advances in computer technology and software have provided new therapeutic options in the treatment of aphasia. Computer programs allow clinicians to easily design activities, select stimulus items, present cues, and individualize reinforcements.26 Software programs can also be used to turn a computer into a speech output communication device, allowing people with severe aphasia to produce phrases and sentences of varying degrees of complexity.27,28 These programs often contain features such as word prediction and graphic cues to facilitate correct sentence structure. Video technology has allowed individuals with aphasia to follow prerecorded mouth movements with auditory and written cues to aid word retrieval for full sentences and even longer narratives.28 The growing popularity of user-friendly smart phones and mobile technologies has allowed individuals with aphasia and other speech and language disorders easy access to tools for enhancing communication including photos, videos, maps, prerecorded messages, and text support. The field of telerehabilitation has developed from these advances in technology to allow evaluation and treatment in the home environment. Recent changes in reimbursement for aphasia therapy have promoted the development of the “Life-Participation Approach to Aphasia.” This philosophy focuses on longterm life goals, incorporating “aphasia friendly” environments, use of communication partners, and identification of barriers to life participation.29
Dysarthria The rehabilitation of dysarthria is influenced by the specific subtype of dysarthria. Approaches to treatment include medical intervention, oral prosthetic devices, and behavioral management.6 People with dysarthria due to Parkinson disease may benefit from dopamine agonists to enhance motor and muscular activities. Palatal lifts and voice amplifiers are commonly used to improve intelligibility. A palatal lift and augmentation prosthesis has been used successfully in conjunction with behavioral management.30 Behavioral management of dysarthria involves muscle strengthening (e.g., lip closure, tongue protrusion, tongue elevation), improvement of breath support, and modification of posture. The individual with dysarthria learns to use compensatory techniques to decrease rate of speech, increase loudness, and “overarticulate.” As with aphasia, families and caregivers are educated in strategies to maximize communication. Treatment of severe dysarthria, anarthria, or aphasia may include the use of augmentative communication systems in which individuals use pictures, written words, alphabet or pictograph boards, or computer-based technologies to enhance communication. Some individuals can use computer systems that produce synthesized speech, offering a wide variety of communication topics and personalization to the individual needs.
Apraxia of Speech Treatment of apraxia of speech involves techniques to elicit accurate voluntary speech production. Various interventions incorporate multimodality cues, such as modeling mouth
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and lip movements, using verbal cues to describe accurate tongue and lip placement, and intoning words and sentences. Treatment approaches often incorporate the use of rate- and rhythm-control strategies.4 For severe cases, alternative communication strategies—such as writing, drawing, and communication books as well as computer technologies and software—are used to augment or replace speech.
Dysphonia Therapeutic management of dysphonia is targeted at the underlying disorder and the pathophysiologic process.31 Vocal hygiene education and proper voicing techniques can improve vocal quality for individuals with vocal nodules due to laryngeal hyperfunction (vocal abuse). Techniques to enhance vocal fold approximation are useful in individuals with vocal cord motion impairments. Laryngitis due to gastroesophageal reflux disease can be treated with a combination of voice therapy and a vigorous antireflux medication regimen including proton pump inhibitors.32 Hypophonia, a common speech dysfunction found in individuals with Parkinson disease, is characterized by decreased vocal loudness. An evidence-based protocoldriven voice therapy that has historically been used successfully with Parkinson disease individuals is the Lee Silverman Voice Treatment-LOUD (LSVT-LOUD), which focuses on factors such as neuroplasticity and the principles of motor learning. LSVT is a high-effort intensive treatment that aims at increasing vocal intensity through the increase in subglottal air pressure, or enhanced respiratory effort, for more effective cordal adduction and vibration.33
Procedures Injection of a paralyzed vocal cord with Gelfoam or Teflon can increase its mass, bringing the medial edge of the cord closer to the midline. This facilitates contact with the mobile contralateral vocal cord, thereby improving phonation. This solution may be only temporary, and at times surgery is needed. For cases of spasmodic dysphonia, the use of botulinum toxin and injection into the affected muscles can result in improved voice by correcting abnormal motion of the vocal folds.34
Technology There is increasing interest in the application of cortical stimulation as an adjuvant strategy in aphasia rehabilitation to enhance the recovery process. Noninvasive brain stimulation technologies such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been used in the treatment of aphasia. TMS is a procedure that uses magnetic fields to create electric currents in discrete brain areas; this can lead to increases or decreases in excitability of the affected cortex that last beyond the duration of the treatment itself. It has been reported to improve naming ability in chronic stroke patients with nonfluent aphasia since 2005 and possibly also phrase length during propositional speech. Studies have found duration of benefit from 2 months to 2 years after stimulation.35 Two main hypotheses of neurologic mechanisms have been considered. One hypothesis uses continuous cortical
stimulation to modify perilesional inhibition; the other uses intermittent cortical stimulation during speech therapy treatment to explore synaptic plasticity and long-term potentiation or depression.36 In the treatment of aphasia, the attempt is to inhibit the intact right hemisphere with the hypothesis that maladaptive activity in the right hemisphere limits language recovery in the impaired left hemisphere. This treatment essentially favors the reorganization of left hemispheric language networks.37 tDCS and the modulation of cortical excitability has shown promise for the augmentation of cognition and the enhancement of working memory and attention.35 With these neurostimulation techniques as with traditional therapies, there remains a large variability regarding stimulation parameters, including montage type, current stimulation, session duration, and number and frequency of treatment sessions. Constraint-induced aphasia therapy (CIAT) has been shown to be effective in the treatment of aphasia and is based on the principles of constraint induced movement therapy or learned nonuse of affected limbs after stroke. Aphasia patients often use nonverbal communication strategies such as gesturing or pantomiming. CIAT discourages these strategies and encourages only attempts at verbal expression to communicate needs.38 Melodic intonation therapy (MIT) is a treatment strategy that uses musical and rhythmic intonations of words and sentences to enhance brain plasticity. As the right brain is felt to have the ability to process musical stimuli and intonation, it is felt that dysfunctions in the left brain can undergo plastic changes by stimulation of functions of the intact right brain, such as music processing. The goal of MIT is to stimulate language recovery in the damaged left brain by the use of music with its melodic patterns, rhythms, and inflections.39
Surgery Surgery is sometimes needed for treatment of voice disorders. Individuals with mass lesions of the larynx may need surgical excision. For individuals with unilateral vocal cord paralysis, a surgical procedure can bring the paralyzed cord closer to the midline to achieve appropriate glottal closure. Implantation of a small device into the paralyzed hemilarynx, displacing the paralyzed cord toward the midline, can provide a lasting improvement in voice quality. Structural lesions (e.g., cleft palate) or functional disorders (e.g., weakness of the palatal elevators) may cause an inadequate seal of the velopharyngeal isthmus (the space between the soft palate and the pharyngeal walls); in either case, a surgical procedure to narrow the defect can sometimes provide improved speech quality.
Potential Disease Complications Individuals with severe speech and language disorders may suffer extreme psychosocial consequences, including isolation, unemployment, anxiety, depression, alienation, ostracism, and inability to fulfill essential family roles. Aphasia has been shown to be a risk factor for disability after stroke and plays a significant role in quality-of-life issues.10
CHAPTER 155 Speech and Language Disorders
Potential Treatment Complications Injection or surgical implant of the larynx may result in complications including infection, hemorrhage, and local tissue trauma. Injected material may gradually be displaced and lose effectiveness, but this rarely leads to serious sequelae. After botulinum toxin injection, the vocal folds may become immobilized in the medial position, but this seldom results in airway obstruction. Adjacent spread of the botulinum toxin into surrounding muscles may worsen the voice disorder or produce dysphagia.40
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