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Pediatric Assessment of the Child with Developmental Delay
THE CHILD WITH DEVELOPMENTAL DISABILITIES
0031-3955/93 $0.00 + .20
PEDIATRIC ASSESSMENT OF THE CHILD WITH DEVELOPMENTAL DELAY Susan E. Levy, MD, and Susan L. Hyman, MD
The American Academy of Pediatrics recommends developmental screening as a routine part of health maintenance visits.4, 5 Children suspected of having developmental delay on the basis of this pediatric screening should undergo more specific developmental and medical assessment to determine if a developmental disability exists and the range of associated deficits. Lowfrequency, high-morbidity developmental disabilities such as cerebral palsy, mental retardation, and sensory impairments are more likely to be identified in the preschool years, whereas low-morbidity, high-frequency disorders including learning disabilities and attention-deficit hyperactivity disorder (ADHD) are more likely to be identified in school-aged children (Table 1).38 This article reviews aspects of the developmental history, physical and neurologic examination, and laboratory tests that aid the pediatrician in the early identification of developmental disability. EARLY IDENTIFICATION
Early identification is important because of the potential for improvement of outcome through educational and rehabilitative services for children with, or at risk for, developmental disability. The most common presentation of a developmental disability is failure to achieve age-appropriate developmental skills. In the first months of life, abnormal development is indicated by a poor suck, floppy or spastic tone, and a lack of visual or auditory response to
From the Developmental Pediatrics Training Program, Children's Seashore House; and The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania (SEL); and Division of Behavioral and Developmental Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland (SLH)
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Table 1. IDENTIFICATION RATES OF DEVELOPMENTAL DISABILITIES Prevalence, Cases Per 100030,50 Mental retardation Learning disability ADHD Cerebral palsy Visual impairment Hearing impairment
25 75 150
2-3 0.3-0.6 0.8-2
MD Is First to Make Diagnosis (% of time)38
Mean Age at Identification by MD (mo)38
76 12 44 99 87 64
39 69 59 10
55 39
environmental stimuli. Later in the first year, motor delay in sitting and crawling suggests a developmental delay. In the second and third year, language and behavioral abnormalities point to developmental disabilities. And by school entry, evidence of learning disabilities and ADHD may be present. One important reason for early identification is to have the child and family participate in one of the recently mandated educational and treatment programs. Table 2 summarizes the federal legislation that mandates free and appropriate public education for children with disabilities from birth to 21 years. This legislation acknowledges the need for coordinated services, including health care and parent involvement. Under the Infants and Toddlers with Disabilities Program (PL99-457), the pediatrician serves as a member of the interdisciplinary assessment and treatment team, an advocate for the child, and a consultant to schools about chronic illness, development, genetics, and medical issues. B The pediatrician may be the first or only professional in contact with young children and their families prior to school entry. Thus, the pediatrician must become skilled in recognizing, evaluating, managing, and referring for additional assessment or community services preschool aged children with, or at risk for, developmental disabilities. 8 In addition, the pediatrician must be comfortable in communicating diagnostic information to the family and providing ongoing support.
DEVELOPMENTAL ASSESSMENT
Early identification of developmental disability depends on a three-part process that includes a medical and developmental history, physical and neurologiC examination, and developmental screening. The medical and social history provides information important in identifying children at biologic or environmental risk for developmental disability. Historical risk factors for developmental disability include prematurity, adverse prenatal and perinatal events, maternal illness, maternal substance abuse, genetic disorders, and sociocultural factors (see the article by Allen elsewhere in this issue). The presence of multiple risk factors increases the chance of developmental disability.
Developmental History
A history of delayed or uneven acquisition of milestones in any sphere of development, including cognition, speech and language, fine and gross motor
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Table 2. FEDERAL LEGISLATION FOR EDUCATION OF CHILDREN WITH DISABILITIES PL
94-142
Date
Title
1975 Education for All Handicapped Children Act
94-142 1975 Preschool Incentive Program 99-457 1986 Preschool Incentive Program amended
101-476 1990 Individuals with Disabilities Education Act, Infants and Toddlers with Disabilities Program
Description Mandates free appropriate public education for school-aged children with developmental disabilities Funds states to develop services for children 3-5 years of age Funds services to children younger than 3 Extends services to chidren 0-3 years by 1993
From Blackman JA, Healy A, Ruppert ES: Impetus from Public Law 99-457. Pediatrics 89:98-102, 1992; with permission.
skills, adaptive skills, or psychosocial skills, should alert the pediatrician to the need for further evaluation. Parental assessment of their child's function is important historical information. Glascoe et aPI 22 reported that parental suspicion of language delay was a sensitive indicator of language delay and did not depend on the level of parental education. Coplan et aP4 also found parental assessment of their child's speech and language comprehension to be well correlated with the results of formal cognitive testing. Yet, other investigators have found that many parents had significant gaps of knowledge about more generalized developmental progress and unreliable recall of milestones. 32, 42 This is more likely to occur when parents lack knowledge of child development, when prior health professionals have not acknowledged their concerns, or when the parents deny the existence of a problem altogether. 17 An organized developmental history begins with tracking developmental milestones at routine health maintenance visits (see the article by Batshaw elsewhere in this issue), By following a child's milestones, the rate of progression can be monitored over time, and the consistency across developmental areas can be evaluated. A developmental quotient can be calculated for each sphere of development (developmental quotient [DQJ = {functioning agel chronologic age} x 100). A differential between spheres of development, such as a motor DQ of 40 versus a language DQ of 100 could implicate the diagnosis of cerebral palsy. Declining developmental quotients might alert the pediatrician to the pOSSibility of a neurodegenerative disorder. The Physical Examination
The general physical and neurologic examination is an integral part of the evaluation of the child with developmental delay. Characteristic findings of growth abnormalities, major and minor congenital anomalies, skin findings, organomegaly, and eye findings may help determine cause (Tables 3 and 4). Hearing and Vision Screening
Hearing and vision screening should be part of the routine well child examination. The measurement of hearing acuity in any child with a receptive
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Table 3. PHYSICAL EXAMINATION: CLUES TO CERTAIN CONDITIONS ASSOCIATED WITH DEVELOPMENTAL DISABILITY Growth Parameters
Congenital Anomalies
Skin Findings
Organomegaly
Eye Findings
Head circumference: -Microcephaly « third percentile for age) correlates highly with cognitive deficits; progressive microcephaly may signify a neurodegenerative disorder -Macrocephaly (> 97th percentile for age) may be an indicator of disorders including hydrocephalus, lysosomal storage disorders, Sotos syndrome, neurofibromatosis Stature and/or obesity: -Short stature: Turner syndrome (associated with learning disabilities) and Williams syndrome (mental retardation) -Obesity: Prader-Willi syndrome (mental retardation) and Beckwith-Wiedemann syndrome -Tall stature: Sotos syndrome Certain congenital defects such as isolated congenital heart disease or cleft palate may be associated with mild developmental delay (e.g., motor or speech delay) 1.6. 34 without having an impact on cognitive development. When major anomalies are clustered together as a syndrome, such as Down syndrome or trisomy 18, mental retardation is usually present. Orthopedic contractu res due to arthrogryposis or limb reduction deformities may result in only motor impairment, or may be part of an underlying multisystemic disorder such as a congenital myopathy. Developmental disabilities are more commonly found in children with neurocutaneous syndromes including neurofibromatosis (learning disabilitf1), tuberous sclerosis (mental retardation in about half 47), and Sturge Weber (mental retardation). Presence of organomegaly (e.g., hepatosplenomegaly) provides a clue that a neurodegenerative disorder may be present, including the mucopolysaccharidoses, gangliosidoses, Gaucher's disease, glycogen storage disease, Niemann-Pick disease, Zellweger disease, galactosemia, and others. The eye examination may give clues for specific syndromes. 26 Examples of abnormalities associated metabolic disorders include lens dislocation (homocystinuria), corneal clouding, mucopolysaccharidoses, cataracts (galactosemia), retinal pigmentation changes (Tay-Sachs), optic atrophy (adrenoleukodystrophy).
or expressive language delay is essential to rule out a significant hearing loss. Hearing also should be monitored closely in children with a history or physical findings suggestive of a hearing loss (Table 5). The cause of the hearing loss may be related to the etiology of a developmental disability (e.g., in congenital cytomegalovirus infection, hearing loss, and microcephaly). Children at high risk for visual impairment include premature infants, children with cerebral palsy, and children with genetic syndromes associated with visual impairment. Referral to a pediatric ophthalmologist may help differentiate cortical blindness from specific ocular abnormalities, which may be characteristic of a syndrome. The type of hearing and vision screening test used depends on the cognitive level of the child. Children with developmental disabilities are often difficult to test with the commonly used Snellen vision charts, the Titmus hearing tester, and audiometry. Tests designed for younger children such as the Teller
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Table 4. EXAMPLES OF MINOR ANOMALIES AND ASSOCIATED SYNDROMES Head
Face
Eyes
Ears
Nose
Mouth
Teeth
Hair
Neck Chest Genitalia Extremities
Spine Skin
Flat occiput: Down syndrome, Zellweger syndrome Prominent occiput: trisomy 18 Delayed closure of sutures: hypothyroidism Craniosynostosis: Crouzon syndrome, Pfeiffer syndrome Delayed fontanel closure: hypothyroidism, Down syndrome Midface hypoplasia: fetal alcohol syndrome, Down syndrome Triangular facies: Russell-Silver syndrome, Turner syndrome Coarse facies: mucopolysaccharidoses, Sotos syndrome Prominent nose and chin: fragile X syndrome Flat facies: Apert syndrome, Stickler syndrome Round facies: Prader-Willi syndrome Hypertelorism: fetal hydantoin syndrome, Waardenburg syndrome Hypotelorism: holoprosencephaly sequence, maternal PKU effect Inner canthal folds/Brush field spots: Down syndrome Slanted palpebral fissures: trisomies Prominent eyes: Apert syndrome, Beckwith-Wiedemann syndrome Lisch nodules: neurofibromatosis Large pinnae/simple helices: fragile X syndrome Malformed pinnae/atretic canal: Treacher Collins syndrome, CHARGE association Low set ears: Treacher Collins syndrome, trisomies Anteverted nares/synophrys: de Lange syndrome Broad nasal bridge: fetal drug effects, fragile X syndrome Low nasal bridge: achondroplasia, Down syndrome Prominent nose: Coffin-Lowry syndrome, Smith-Lemli-Opitz syndrome Long filtrum/thin vermillion border: fetal alcohol effects Cleft lip and palate: isolated or part of syndrome Micrognathia: Robin sequence, trisomies Macroglossia: hypothyroidism, Beckwith-Wiedemann syndrome Anodontia: ectodermal dysplasia Notched incisors: congenital syphilis Late dental eruption: Hunter syndrome Wide-spaced teeth: de Lange syndrome, Angelman syndrome Hirsuitism: Hurler syndrome Low hairline: Klippel-Feil sequence Sparse hair: Menkes, argininosuccinic acidemia Abnormal hair whorls/posterior whorl: Down syndrome Abnormal eyebrow patterning: Waardenburg syndrome Webbed neck/low posterior hair line: Turner syndrome Shield shaped chest: Turner syndrome Macroorchidism: fragile X syndrome Hypogonadism: Prader-Willi syndrome Short limbs: achondroplasia, rhizomelic chondrodysplasia Small hands: Prader-Willi syndrome Clinodactyly: trisomies including Down syndrome Polydactyly: trisomy 13 Broad thumb: Rubinstein-Taybi syndrome Syndactyly: de Lange syndrome Transverse palmer crease: Down syndrome Joint laxity: Down syndrome, fragile X syndrome Phocomelia: de Lange syndrome Sacral dimple/hairy patch: spina bifida Hypopigmented macules/adenoma sebaceum: tuberous sclerosis Cafe au lait spots and neurofibromas: neurofibromatosis Linear depigmented nevi: hypomelanosis of Ito Facial port wine hemangioma: Sturge-Weber syndrome Nail hypoplasia or dysplasia: fetal alcohol syndrome, trisomies
Increased incidence of minor anomalies have been reported in cerebral palsy, mental retardation, learning disabilities, and autism.35. 43 The presence of three or more minor anomalies places a child at greater risk to have a major anomaly and the diagnosis of a specific syndrome. 26
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Table 5. REASONS FOR MEASURING/MONITORING HEARING ACUITY Receptive or expressive language delay Significant articulation defect(s) or abnormal speech Small premature babies, weighing < 1500 g Exposure to aminoglycoside antibiotics Family history of hearing impairment Congenital infections or central nervous system infection(s) Chronic serous otitis media Craniofacial dysmorphic syndromes Lack of auditory orientation by 6 months
Vision Cards, preferential looking, auditory evoked responses, and behavioral audiometry may be more appropriate for these children (see the article by Menacker elsewhere in this issue).
Neurologic Examination
The classic neurologic examination (Table 6) permits identification of upper and lower motor neuron disorders and delineates motor impairment. Deep tendon reflexes, muscle tone, sensation, adventitious movements, and gait all should be evaluated in an age dependent fashion. Assessment of neuromotor maturation over time is necessary to distinguish mild motor delays from major disorders of neurologic function such as cerebral palsy. Neurodevelopmental maturation in infants is assessed through an examination of primitive reflexes and postural responses,l1 the classic neurologic examination, and acquisition of motor milestones (see Table 3 in the article by Batshaw elsewhere in this issue). Primitive reflexes, the obligatory movement patterns present at term birth, become integrated in the first 6 months of life; in their place the postural equilibrium responses emerge (see the article by Kurtz and Scull elsewhere in this issue). With this transition, volitional movement patterns develop, and new motor milestones can be achieved. Asymmetry of muscle tone or function, hypertonia, hypotonia, or persistence of primitive reflexes interferes with the acquisition of motor milestones and suggests neuromotor dysfunction. A review of the progression of motor milestones is a useful tool to help differentiate motor delay from disability. Age of attainment of each motor milestone may be compared with established norms by calculating a DQ. In Table 6. NEUROLOGIC EXAMINATION OF INFANTS AND TODDLERS WITH DEVELOPMENTAL DELAY
Classic Neurologic Examination Cranial nerves Deep tendon reflexes Tone (proximal, axial, and distal) Strength (proximal and distal) Cerebellar signs Extended Neurologic Examination (look at age of accomplishment or resolution, symmetry, and quality) Primitive reflexes (e.g., Moro, asymmetric tonic neck, tonic labyrinthine) Postural responses (e.g., neck righting, propping response) Neuromaturational examination/motor milestones
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examining a series of "mini DQs" the pediatrician can get a sense of the rate of progression of milestones and determine if there are specific problem areas or slowing of development. By coupling these findings with the neurologic examination (e.g., findings of hypertonia, hyperreflexia, or persistent primitive reflexes), the pediatrician can make the diagnosis of cerebral palsy or other motor dysfunction.
Developmental Screening Studies have demonstrated that pediatricians are unreliable in determining the presence of developmental delay by clinical judgment alone." 28 Yet despite the recommendation of routine developmental screening, studies have shown that few pediatricians use standardized instruments to detect developmental delay.42 As a consequence, almost half of children with mental retardation are not identified until after 3 years of age. 38 Hopefully, the recent emphasis on developmental and behavioral curricula in pediatric training programs will improve the pediatrician's skills in the use of standardized instruments and result in earlier identification of developmental disabilities. Pediatricians who do perform developmental screening have used many different techniques, including a review of developmental milestones with parents, performance of an informal collection orage-appropriate tasks, reliance on clinical judgment, and performance of all or part of formal screening standardized test(s) (Table 7).18 The most reasonable and effective method for developmental screening by the busy pediatrician is a combination of historical review of milestones (in comparison with established norms), observation of developmental skills using a standardized instrument, and the neurologic examination. When suspicion of developmental delay or disability is confirmed, the pediatrician may then pursue additional evaluations or refer the child for more comprehensive evaluation by a child development team. With the implementation of Part H of PL 99-457, specific standards for individual and comprehensive team evaluation must be established to determine eligibility for early intervention services of infants· and toddlers at risk for developmental delay. Pediatricians need to be trained to carry out these evaluations in a cost effective manner. The administration of a standardized screening instrument provides an opportunity for parents to express their concerns and for anticipatory guidance to take place. Tests designed for screening populations should have adequate sensitivity to identify individuals with a developmental disorder and sufficient specificity to avoid over-identification. Critics of routine developmental screening suggest that currently available screening instruments do not meet the conventional criteria for sensitivity or specificity.18 Table 7 lists some commonly used global and language-based developmental screening tests for infants and toddlers that can be administered in the pediatrician's office. These tools use parental interview or direct assessment. Children who are considered abnormal by the test norms or by the clinical judgment of the pediatrician should receive a more thorough diagnostic assessment. A pediatrician who suspects developmental delay may consult a variety of subspecialists who can assist in diagnosis and management. One such individual is the developmental pediatrician who can serve as a referral source for coordination of the assessment and management of the child at risk for developmental disability. In many metropolitan areas, coordinated interdisci-
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Table 7. DEVELOPMENTAL SCREENING INSTRUMENTS Description
Screening Tool GENERAL SCREENING TOOLS Batelle Developmental Inventory Screening test'l7 Denver 11'9, 20
Developmental Indicators for Assessment of Learning-Revised (DIAL-R)33
Infant Monitoring System 9
The Revised Developmental Screening Inventory (1980)27
LANGUAGE SCREENING TOOLS CLAMS (Clinical Linguistic Auditory Milestones Scale)'2 ELM (Early Language Milestone Scale)13
PPVT-R (Peabody Picture Vocabulary Test-Revised)"' 16, 31 REEL (Receptive-Expressive Emergent Language)'0
14
Screens multiple areas by combination of observation and history. Ages years. Global screening, including personal/social, fine motor/adaptive, gross motor skills, Scored as pass/fail/questionable, Ages 0-6 years. Screens fine and gross motor, expressive and receptive language, and cognitive/ academic skills by direct observation. Ages 2-6 years. Screening by parent report, assessing communication, gross and fine motor, adaptive and personal-social skills, Ages 0-36 months. Screens gross and fine motor, adaptive, problem-solving and language skills. Ages 0-3 years.
o-s
Assesses receptive and expressive language by observation and parental interview. Ages 1-36 months. Receptive and expressive language (pass/ fail) by interview, observation, and test administration. Ages 0-36 months. Single word receptive vocabulary. Ages 26 months to adult. Receptive and expressive language age, by parental interview. Ages 0-3 years,
plinary evaluations can be obtained though child development clinics, academic medical centers, and university affiliated programs. Upon completion of the evaluation, the child should be referred for intervention through the Division of Special Education. This can occur concurrently with other referrals for specific diagnosis through the health care system. MEDICAL TESTING
Does every child with developmental delay need a costly array of diagnostic procedures, including brain imaging studies, chromosomal karyotyping, metabolic screening, and electroencephalography (EEG)? Existing studies do not support the use of extensive ~esting of all children with developmental disabilities. 44 A careful history and physical examination with judicious use of consultants can help the clinician exercise prudence in the medical evaluation of the child with developmental disability. Some children need little or no medical testing as part of an evaluation for developmental delay; others require an extensive examination. Chromosomal Karyotyping
Karyotyping using peripheral blood leukocytes provides diagnostic information concerning chromosomal disorders. Children with a major anomaly or
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multiple minor anomalies compatible with known chromosomal syndromes should have karyotyping performed. A controversial issue is the determination of which persons with developmental disabilities should be tested for fragile X syndrome, the most common inherited disorder resulting in mental retardation. Fragile X syndrome produces one case of mental retardation in every 1000 to 1500 males. 48 In addition, one quarter to one third of heterozygous females have mental retardation. 23 Thus, it becomes a question of whether all children with mental retardation without a clear cause should be tested for fragile X syndrome. With the development of the less expensive DNA analysis for the fragile site of the X chromosome, it is likely that in the future fragile X will be tested for in increasing numbers of males with mental retardation40 and autism.'9
Electroencephalogram
In the general population the prevalence of seizure disorders is 0.5%. In individuals with developmental disabilities residing in residential facilities, the prevalence ranges from 12% to 58%.3 Seizures are not as common in children with less severe developmental disabilities. As in the population at large, generalized tonic-clonic seizures are the most frequent seizure type in children with developmental disabilities. There are specific epileptic syndromes, however, such as infantile spasms and Lennox-Gastaut syndrome, that are strongly associated with developmental disabilities. EEGs should be performed in any child who has a history of seizures or seizure-like episodes!S Yet, pediatricians who care for children with developmental disabilities are often asked to obtain EEGs to exclude ictal events as the cause of behavior dysfunction or lapses of attention. There is little evidence to support ictal events as a common cause of aggression, tantrums, or self-injurious behavior in these children. 2' Most of these behaviors are based on responses to the environment (see the article by Parrish elsewhere in this issue). Therefore, before attributing unusual behaviors to ictal events, a careful analysis of psychological and environmental variables needs to be performed. An advance in EEG technology that may aid in developmental diagnosis and in research into pathologic mechanisms of brain injury is brain electrical activity mapping (BEAM). This approach differs from conventional EEGs in the use of summation over time. Current research suggests that compared with a control population, differences exist in BEAM studies in individuals with learning disabilities, autism, and ADHD.15 Further research is necessary to determine if it has a role in routine clinical evaluation of children with these disorders.
Brain Imaging Studies
Computed tomography (CT) and magnetic resonance (MR) imaging have become routine tools in evaluating children with developmental disabilities. The question is, does every child with mental retardation or cerebral palsy really need a neuroimaging study? Computed tomography scans provide excellent resolution of intracranial structures with the ability to image bony structures and identify intracranial calcifications. To delineate grey versus white matter, injected contrast material is used. MR imaging scans make this differentiation and permit assessment of
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the development of normal myelinization without the need for contrast. MR imaging scans generally give a clearer picture of the brain than CT scans but do not accurately detect calcifications. Currently, CT studies require an individual to remain still for up to 20 to 30 minutes, whereas MR imaging studies can take twice as long. This means that young children and children with mental retardation usually require sedation. There are certain conditions or disorders associated with developmental disabilities in which the identification of intracranial pathology may be useful in diagnosis, genetic counseling, or determination of prognosis (Table 8), although it is unlikely to alter clinical management. 29, 36 For example, cortical atrophy represents a common but nonspecific finding in almost half of children with cerebral palsy46 and in about one quarter of children with mental retardation without known cause. 29, 36 Overall, neuroimaging studies are not routinely indicated as part of the medical evaluation for developmental disability. An unexpected change in behavior, head circumference, motor status, cognitive abilities, neurologic examination, or seizure frequency may indicate the need for a neuroimaging study, however.
Metabolic Screening It should be recognized that some metabolic screening is done routinely on all children in the newborn period. All states test for phenylketonuria and congenital hypothyroidism, and many states test for other inborn errors of metabolism including galactosemia, biotinidase deficiency, and maple syrup urine disease. Once a child has been diagnosed as having mental retardation, the question often arises concerning the need for additional metabolic investiTable 8. SPECIFIC DISORDERS AND NEUROIMAGING FINDINGS Disorder
Intrauterine infection Tuberous sclerosis Craniofacial anomalies Microcephaly
Genetic syndromes Aicardi's syndrome Sotos syndrome Smith-Lemli-Opitz Hypoxic-ischemic encephalopathy
Post central nervous system infection Intraventricular hemorrhage
Findings on Neuroimaging
Intracranial calcifications Periventricular tubers (may obstruct CSF flow and lead to hydrocephalus) Parenchymal abnormalities (e.g., holoprosencephaly, agenesis of corpus callosum, schizencephaly) Parenchymal abnormalities Intracranial calcifications (related to etiology for microcephaly) Atrophy Agenesis of corpus callosum Ventricular dilatation Severe parenchymal abnormalities Nonspecific findings: ventricular dilatation, atrophy Predisposing conditions to hypoxemia: structural parenchymal lesions (including holoprosencephaly, agenesis of corpus callosum, gyral abnormalities, schizencephaly) Nonspecific findings: ventricular dilatation, atrophy Specific lesions: infarcts, porencephaly Porencephaly Periventricular leukomalacia
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gation. This most commonly implies plasma amino acids, urine organic acids, and blood lactate. 39 Based on the extremely low prevalence of inborn errors, metabolic screening does not need to be a routine part of an evaluation. If there is a history of intermittent episodes of vomiting and lethargy, failure to thrive, progressive loss of skills or a plateau in milestone acquisition, an unusual body odor, or a suggestive family history, these studies should be performed. If there is significant concern about a metabolic disorder, it is probably best to refer the child to a metabolic specialist. COORDINATION OF CARE
Coordination of the many medical subspecialists and therapists providing services to a child with developmental disabilities is essential for optimal management. In addition to the pediatrician, the members of the interdisciplinary team may include a psychologist, speech and language therapist, occupational therapist, physical therapist, social worker, and special educator. Frequently consulted medical subspecialties include orthopedics, physiatry, genetics, ophthalmology, otolaryngology, child neurology, and child psychiatry. The information from diagnostic and etiologic evaluations outside the school system should be shared with the therapists and educational specialists who determine the child's eligibility for services or with the private therapist who provides care. Ongoing therapeutic services need to be monitored periodically to determine their effectiveness. If services are obtained from more than one source, that is, school and hospital or private therapists, there needs to be a dialogue between professionals so the child and family do not get conflicting advice. The pediatrician may be needed to determine the amount of intervention and to identify changes in medical status that may require alteration in services or reassessment. SUMMARY
With the recent mandate for early intervention services, the pediatrician is more involved than ever in the identification and evaluation of children with developmental disabilities. Developmental surveillance at routine visits and listening to parental concerns are crucial in the early diagnosis of developmental delay so that therapeutic interventions can be provided at a time when there is a good chance of decreasing disability and family stress. Medical evaluations and consultations must be prudent and based on a thorough history and physical. The pediatrician must have the knowledge and skills to coordinate medical care and to counsel and provide support to the child and family as they receive habilitative services and come to terms with the developmental diagnoses. References 1. Aisenberg RB, Rosenthal A, Nadas AS, et al: Developmental delay in infants with
congenital heart disease. Pediatr Cardiol 3:133, 1982 2. Alpeter T: Use of the PPVT-R for intellectual screening with a preschool pediatric sample. J Pediatr Psychol 10:195, 1985
d
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3. Alvarez N: Epilepsy. In Rubin IL, Crocker AC (eds): Developmental Disabilities: Delivery of Medical Care for Children and Adults. Philadelphia, Lea & Febiger, 1989 4. American Academy of Pediatrics, Committee on Practice and Ambulatory Medicine: Recommendations for preventive health care. Pediatrics 81:466, 1988 5. American Academy of Pediatrics, Committee on Children with Disabilities: Screening for Developmental Disabilities. Pediatrics 78:526, 1986 6. Bellinger DC, Wernovsky G, Rappaport LA, et al: Cognitive development of children following early repair of transposition of the great arteries using deep hypothermic circulatory arrest. Pediatrics 87:701, 1991 7. Bierman JM, Connor A, Vaage M, et al: Pediatricians' assessment of the intelligence of two-year-olds and their mental test scores. Pediatrics 34:680, 1984 8. Blackman JA, Healy A, Ruppert ES: Impetus from public law 99-457. Pediatrics 89:98, 1992 9. Bricker D, Squires J: Infant Monitoring System (IMS). Center for Human Development, College of Oregon, Eugene, Oregon, 1989 10. Bzoch KR, League R: Assessing Language Skills in Infancy: A Handbook for the Multidimensional Analysis of Emergent Language. Baltimore, University Park Press, 1971 11. Capute AJ, Accardo PI, Vining EPG, et al: Primitive Reflex Profile. Baltimore, University Park Press, 1978 12. Cap ute AI, Shapiro BK, Wachtel RC, et al: The Clinical Linguistic and Auditory Milestone Scale (CLAMS): Identification of cognitive defects in motor-delayed children. Am J Dis Child 140:694, 1986 13. Coplan J: ELM (Early Language Milestone Scale)-Revised. Tulsa, Modern Education Corporation, 1984 14. Coplan J, Gleason JR, Ryan R, et al: Validation of an early language milestone scale in a high risk population. Pediatrics 70:677, 1982 15. Duffy FH: Clinical value of topographic mapping and quantified neurophysiology. Arch Neurol 46:113, 1989 16. Dunn LM, et al: Peabody Picture Vocabulary Test: Revised. Circle Pines, Minnesota, American Guidance Service, 1981 17. Dworkin PH: British and American recommendations for developmental monitoring: The role of surveillance. Pediatrics 84:1000, 1989 18. Dworkin PH: Developmental screening: Expecting the impossible? Pediatrics 83:619, 1989 19. Frankenberg WK, Dodds 1, Archer P: Denver II: Screening Manual. Denver, Denver Developmental Materials, Inc, 1990 20. Frankenburg WK, Dodds J, Archer P: The Denver II: A major revision and restandardization of the Denver Developmental Screening Test. Pediatrics 1:91, 1992 21. Glascoe FP, Altemeier WA, MacLean WE: The importance of parents' concerns about their child's development. Am J Dis Child 143:955, 1989 22. Glascoe FP, MacLean WE, Stone WL: The importance of parents' concerns about their child's behavior. Clin Pediatr 30:8, 1991 23. Hagerman R1, Jackson C, Amiri K: Girls with fragile X syndrome: Physical and neurocognitive status and outcome. Pediatrics 89:395, 1992 24. Hyman SL, Fisher W, Mercugliano M, et al: Children with self-injurious behavior. Pediatrics 85:437, 1990 25. Jaworski M, Hersh JH, et al: Computed tomography of the head in the evaluation of microcephaly. Pediatrics 78:1064, 1986 26. Jones KL: Smith's Recognizable Patterns of Human Malformation, ed 4. Philadelphia, WB Saunders, 1988 27. Knobloch H, Stevens F, Malone AF: The Revised Developmental Screening Inventory: 1980. Houston, Gesell Developmental Test Materials, 1980 28. Korsch B, Cobb K, Ashe B: Pediatricians' appraisals of patients' intelligence. Pediatrics 27:990, 1961 29. Lingam S, Read S, Holland 1M, et al: Value of computerized tomography in children with non-specific mental subnormality. Arch Dis Child 57:381, 1982 30. Lipkin P: Epidemiology of the developmental disabilities. In Capute AJ, Accardo PJ (eds): Developmental Disabilities in Infancy and Childhood. Baltimore, Paul H. Brookes, 1990
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31. Listernick R, Charrow J: Neurofibromatosis type 1 in childhood. J Pediatr 116:845, 1990 32. McCune YD, Richardson MM, Powell JA: Psychosocial health issues in pediatric practices: Parents' knowledge and concerns. Pediatrics 74:183, 1984
33. MardelI-Czudnoswki C, Goldenberg D: Developmental Indicators for Assessment of Learning-Revised (DIAL-R). Edison, NJ, Childcraft Educational Corporation, 1983 34. Mendoza JC, Wilkerson SA, Reese AH: Follow up of patients who underwent arterial switch repair for transposition of the great arteries. Am J Dis Child 145:40, 1991 35. Miller G: Cerebral palsy and minor congenital anomalies. Clin Pediatr 30:97, 1991 36. Moescher JB, Bennett FC, Cromwell LD: Use of the CT scan in the medical evaluation of the mentally retarded child. J Pediatr 98:63, 1981 37. Newborg J, Stock JR, Wnek L, et al: Batelle Developmental Inventory Screening Test. Allen, Texas, DLM-Teaching Resources, 1984 38. Palfrey JS, Singer JD, Walker DK: Early identification of children's special needs: A study in five metropolitan communities. J Pediatr 11:651, 1987 39. Roth KS: Inborn errors of metabolism: The essentials of clinical diagnosis. Clin Pediatr 30:183, 1991
40. Rousseau F, Heitz D, Biancalana V, et al: Direct diagnosis by DNA analysis of the fragile x syndrome of mental retardation. N Engl J Med 325:1673, 1991 41. Shea V, Fowler MG: Parental and pediatric trainee knowledge of development. J Dev Behav Pediatr 4:21. 1983 42. Shonkhoff JP, Dworkin PH, Leviton A, et al: Primary care approaches to developmental disabilities. Pediatrics 64:506, 1979 43. Smalley SL, Asarnow RF, Spence A: Autism and genetics. Arch Gen Psychiatry 45:953, 1988
44. Smith D, Simmons ER: Rational diagnostic evaluation of the child with mental deficiency. Am J Dis Child 129:1285, 1975 45. Stephenson JBP: Fits and faints. Clinics in Developmental Medicine. Philadelphia, JB Lippincott, 1990, p 109 46. Taudorf K, Melchior JC: CT findings in spastic cerebral palsy, clinical aetological and prognostic aspects. Neuropediatrics 15:120, 1984 47. Tunnessen WW: Denouement and discussion: Tuberous sclerosis. Am J Dis Child 146:253, 1991
48. Turner G, Robinson H, Laing S, et al: Preventive screening for the fragile X syndrome. N Engl J Med 315:607, 1986 49. Wright HH, Young SR, Edwards JG, et al: Fragile x syndrome in a population of autistic children. J Am Acad Child Adolesc Psychiatry 25:641, 1986 50. Yeargain-Allsopp M, Murphy Cc, Oakley GP, et al: A multiple-source method for studying the prevalence of developmental disabilities in children: The metropolitan Atlanta developmental disabilities study. Pediatrics 89:624, 1992
Address reprint requests to Susan E. Levy, MD Division of Child Development and Rehabilitation Children's Seashore House 3405 Civic Center Boulevard Philadelphia, PA 19104
0031-3955/93 $0.00 + .20
PEDIATRIC ASSESSMENT OF THE CHILD WITH DEVELOPMENTAL DELAY Susan E. Levy, MD, and Susan L. Hyman, MD
The American Academy of Pediatrics recommends developmental screening as a routine part of health maintenance visits.4, 5 Children suspected of having developmental delay on the basis of this pediatric screening should undergo more specific developmental and medical assessment to determine if a developmental disability exists and the range of associated deficits. Lowfrequency, high-morbidity developmental disabilities such as cerebral palsy, mental retardation, and sensory impairments are more likely to be identified in the preschool years, whereas low-morbidity, high-frequency disorders including learning disabilities and attention-deficit hyperactivity disorder (ADHD) are more likely to be identified in school-aged children (Table 1).38 This article reviews aspects of the developmental history, physical and neurologic examination, and laboratory tests that aid the pediatrician in the early identification of developmental disability. EARLY IDENTIFICATION
Early identification is important because of the potential for improvement of outcome through educational and rehabilitative services for children with, or at risk for, developmental disability. The most common presentation of a developmental disability is failure to achieve age-appropriate developmental skills. In the first months of life, abnormal development is indicated by a poor suck, floppy or spastic tone, and a lack of visual or auditory response to
From the Developmental Pediatrics Training Program, Children's Seashore House; and The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania (SEL); and Division of Behavioral and Developmental Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland (SLH)
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Table 1. IDENTIFICATION RATES OF DEVELOPMENTAL DISABILITIES Prevalence, Cases Per 100030,50 Mental retardation Learning disability ADHD Cerebral palsy Visual impairment Hearing impairment
25 75 150
2-3 0.3-0.6 0.8-2
MD Is First to Make Diagnosis (% of time)38
Mean Age at Identification by MD (mo)38
76 12 44 99 87 64
39 69 59 10
55 39
environmental stimuli. Later in the first year, motor delay in sitting and crawling suggests a developmental delay. In the second and third year, language and behavioral abnormalities point to developmental disabilities. And by school entry, evidence of learning disabilities and ADHD may be present. One important reason for early identification is to have the child and family participate in one of the recently mandated educational and treatment programs. Table 2 summarizes the federal legislation that mandates free and appropriate public education for children with disabilities from birth to 21 years. This legislation acknowledges the need for coordinated services, including health care and parent involvement. Under the Infants and Toddlers with Disabilities Program (PL99-457), the pediatrician serves as a member of the interdisciplinary assessment and treatment team, an advocate for the child, and a consultant to schools about chronic illness, development, genetics, and medical issues. B The pediatrician may be the first or only professional in contact with young children and their families prior to school entry. Thus, the pediatrician must become skilled in recognizing, evaluating, managing, and referring for additional assessment or community services preschool aged children with, or at risk for, developmental disabilities. 8 In addition, the pediatrician must be comfortable in communicating diagnostic information to the family and providing ongoing support.
DEVELOPMENTAL ASSESSMENT
Early identification of developmental disability depends on a three-part process that includes a medical and developmental history, physical and neurologiC examination, and developmental screening. The medical and social history provides information important in identifying children at biologic or environmental risk for developmental disability. Historical risk factors for developmental disability include prematurity, adverse prenatal and perinatal events, maternal illness, maternal substance abuse, genetic disorders, and sociocultural factors (see the article by Allen elsewhere in this issue). The presence of multiple risk factors increases the chance of developmental disability.
Developmental History
A history of delayed or uneven acquisition of milestones in any sphere of development, including cognition, speech and language, fine and gross motor
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Table 2. FEDERAL LEGISLATION FOR EDUCATION OF CHILDREN WITH DISABILITIES PL
94-142
Date
Title
1975 Education for All Handicapped Children Act
94-142 1975 Preschool Incentive Program 99-457 1986 Preschool Incentive Program amended
101-476 1990 Individuals with Disabilities Education Act, Infants and Toddlers with Disabilities Program
Description Mandates free appropriate public education for school-aged children with developmental disabilities Funds states to develop services for children 3-5 years of age Funds services to children younger than 3 Extends services to chidren 0-3 years by 1993
From Blackman JA, Healy A, Ruppert ES: Impetus from Public Law 99-457. Pediatrics 89:98-102, 1992; with permission.
skills, adaptive skills, or psychosocial skills, should alert the pediatrician to the need for further evaluation. Parental assessment of their child's function is important historical information. Glascoe et aPI 22 reported that parental suspicion of language delay was a sensitive indicator of language delay and did not depend on the level of parental education. Coplan et aP4 also found parental assessment of their child's speech and language comprehension to be well correlated with the results of formal cognitive testing. Yet, other investigators have found that many parents had significant gaps of knowledge about more generalized developmental progress and unreliable recall of milestones. 32, 42 This is more likely to occur when parents lack knowledge of child development, when prior health professionals have not acknowledged their concerns, or when the parents deny the existence of a problem altogether. 17 An organized developmental history begins with tracking developmental milestones at routine health maintenance visits (see the article by Batshaw elsewhere in this issue), By following a child's milestones, the rate of progression can be monitored over time, and the consistency across developmental areas can be evaluated. A developmental quotient can be calculated for each sphere of development (developmental quotient [DQJ = {functioning agel chronologic age} x 100). A differential between spheres of development, such as a motor DQ of 40 versus a language DQ of 100 could implicate the diagnosis of cerebral palsy. Declining developmental quotients might alert the pediatrician to the pOSSibility of a neurodegenerative disorder. The Physical Examination
The general physical and neurologic examination is an integral part of the evaluation of the child with developmental delay. Characteristic findings of growth abnormalities, major and minor congenital anomalies, skin findings, organomegaly, and eye findings may help determine cause (Tables 3 and 4). Hearing and Vision Screening
Hearing and vision screening should be part of the routine well child examination. The measurement of hearing acuity in any child with a receptive
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Table 3. PHYSICAL EXAMINATION: CLUES TO CERTAIN CONDITIONS ASSOCIATED WITH DEVELOPMENTAL DISABILITY Growth Parameters
Congenital Anomalies
Skin Findings
Organomegaly
Eye Findings
Head circumference: -Microcephaly « third percentile for age) correlates highly with cognitive deficits; progressive microcephaly may signify a neurodegenerative disorder -Macrocephaly (> 97th percentile for age) may be an indicator of disorders including hydrocephalus, lysosomal storage disorders, Sotos syndrome, neurofibromatosis Stature and/or obesity: -Short stature: Turner syndrome (associated with learning disabilities) and Williams syndrome (mental retardation) -Obesity: Prader-Willi syndrome (mental retardation) and Beckwith-Wiedemann syndrome -Tall stature: Sotos syndrome Certain congenital defects such as isolated congenital heart disease or cleft palate may be associated with mild developmental delay (e.g., motor or speech delay) 1.6. 34 without having an impact on cognitive development. When major anomalies are clustered together as a syndrome, such as Down syndrome or trisomy 18, mental retardation is usually present. Orthopedic contractu res due to arthrogryposis or limb reduction deformities may result in only motor impairment, or may be part of an underlying multisystemic disorder such as a congenital myopathy. Developmental disabilities are more commonly found in children with neurocutaneous syndromes including neurofibromatosis (learning disabilitf1), tuberous sclerosis (mental retardation in about half 47), and Sturge Weber (mental retardation). Presence of organomegaly (e.g., hepatosplenomegaly) provides a clue that a neurodegenerative disorder may be present, including the mucopolysaccharidoses, gangliosidoses, Gaucher's disease, glycogen storage disease, Niemann-Pick disease, Zellweger disease, galactosemia, and others. The eye examination may give clues for specific syndromes. 26 Examples of abnormalities associated metabolic disorders include lens dislocation (homocystinuria), corneal clouding, mucopolysaccharidoses, cataracts (galactosemia), retinal pigmentation changes (Tay-Sachs), optic atrophy (adrenoleukodystrophy).
or expressive language delay is essential to rule out a significant hearing loss. Hearing also should be monitored closely in children with a history or physical findings suggestive of a hearing loss (Table 5). The cause of the hearing loss may be related to the etiology of a developmental disability (e.g., in congenital cytomegalovirus infection, hearing loss, and microcephaly). Children at high risk for visual impairment include premature infants, children with cerebral palsy, and children with genetic syndromes associated with visual impairment. Referral to a pediatric ophthalmologist may help differentiate cortical blindness from specific ocular abnormalities, which may be characteristic of a syndrome. The type of hearing and vision screening test used depends on the cognitive level of the child. Children with developmental disabilities are often difficult to test with the commonly used Snellen vision charts, the Titmus hearing tester, and audiometry. Tests designed for younger children such as the Teller
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Table 4. EXAMPLES OF MINOR ANOMALIES AND ASSOCIATED SYNDROMES Head
Face
Eyes
Ears
Nose
Mouth
Teeth
Hair
Neck Chest Genitalia Extremities
Spine Skin
Flat occiput: Down syndrome, Zellweger syndrome Prominent occiput: trisomy 18 Delayed closure of sutures: hypothyroidism Craniosynostosis: Crouzon syndrome, Pfeiffer syndrome Delayed fontanel closure: hypothyroidism, Down syndrome Midface hypoplasia: fetal alcohol syndrome, Down syndrome Triangular facies: Russell-Silver syndrome, Turner syndrome Coarse facies: mucopolysaccharidoses, Sotos syndrome Prominent nose and chin: fragile X syndrome Flat facies: Apert syndrome, Stickler syndrome Round facies: Prader-Willi syndrome Hypertelorism: fetal hydantoin syndrome, Waardenburg syndrome Hypotelorism: holoprosencephaly sequence, maternal PKU effect Inner canthal folds/Brush field spots: Down syndrome Slanted palpebral fissures: trisomies Prominent eyes: Apert syndrome, Beckwith-Wiedemann syndrome Lisch nodules: neurofibromatosis Large pinnae/simple helices: fragile X syndrome Malformed pinnae/atretic canal: Treacher Collins syndrome, CHARGE association Low set ears: Treacher Collins syndrome, trisomies Anteverted nares/synophrys: de Lange syndrome Broad nasal bridge: fetal drug effects, fragile X syndrome Low nasal bridge: achondroplasia, Down syndrome Prominent nose: Coffin-Lowry syndrome, Smith-Lemli-Opitz syndrome Long filtrum/thin vermillion border: fetal alcohol effects Cleft lip and palate: isolated or part of syndrome Micrognathia: Robin sequence, trisomies Macroglossia: hypothyroidism, Beckwith-Wiedemann syndrome Anodontia: ectodermal dysplasia Notched incisors: congenital syphilis Late dental eruption: Hunter syndrome Wide-spaced teeth: de Lange syndrome, Angelman syndrome Hirsuitism: Hurler syndrome Low hairline: Klippel-Feil sequence Sparse hair: Menkes, argininosuccinic acidemia Abnormal hair whorls/posterior whorl: Down syndrome Abnormal eyebrow patterning: Waardenburg syndrome Webbed neck/low posterior hair line: Turner syndrome Shield shaped chest: Turner syndrome Macroorchidism: fragile X syndrome Hypogonadism: Prader-Willi syndrome Short limbs: achondroplasia, rhizomelic chondrodysplasia Small hands: Prader-Willi syndrome Clinodactyly: trisomies including Down syndrome Polydactyly: trisomy 13 Broad thumb: Rubinstein-Taybi syndrome Syndactyly: de Lange syndrome Transverse palmer crease: Down syndrome Joint laxity: Down syndrome, fragile X syndrome Phocomelia: de Lange syndrome Sacral dimple/hairy patch: spina bifida Hypopigmented macules/adenoma sebaceum: tuberous sclerosis Cafe au lait spots and neurofibromas: neurofibromatosis Linear depigmented nevi: hypomelanosis of Ito Facial port wine hemangioma: Sturge-Weber syndrome Nail hypoplasia or dysplasia: fetal alcohol syndrome, trisomies
Increased incidence of minor anomalies have been reported in cerebral palsy, mental retardation, learning disabilities, and autism.35. 43 The presence of three or more minor anomalies places a child at greater risk to have a major anomaly and the diagnosis of a specific syndrome. 26
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Table 5. REASONS FOR MEASURING/MONITORING HEARING ACUITY Receptive or expressive language delay Significant articulation defect(s) or abnormal speech Small premature babies, weighing < 1500 g Exposure to aminoglycoside antibiotics Family history of hearing impairment Congenital infections or central nervous system infection(s) Chronic serous otitis media Craniofacial dysmorphic syndromes Lack of auditory orientation by 6 months
Vision Cards, preferential looking, auditory evoked responses, and behavioral audiometry may be more appropriate for these children (see the article by Menacker elsewhere in this issue).
Neurologic Examination
The classic neurologic examination (Table 6) permits identification of upper and lower motor neuron disorders and delineates motor impairment. Deep tendon reflexes, muscle tone, sensation, adventitious movements, and gait all should be evaluated in an age dependent fashion. Assessment of neuromotor maturation over time is necessary to distinguish mild motor delays from major disorders of neurologic function such as cerebral palsy. Neurodevelopmental maturation in infants is assessed through an examination of primitive reflexes and postural responses,l1 the classic neurologic examination, and acquisition of motor milestones (see Table 3 in the article by Batshaw elsewhere in this issue). Primitive reflexes, the obligatory movement patterns present at term birth, become integrated in the first 6 months of life; in their place the postural equilibrium responses emerge (see the article by Kurtz and Scull elsewhere in this issue). With this transition, volitional movement patterns develop, and new motor milestones can be achieved. Asymmetry of muscle tone or function, hypertonia, hypotonia, or persistence of primitive reflexes interferes with the acquisition of motor milestones and suggests neuromotor dysfunction. A review of the progression of motor milestones is a useful tool to help differentiate motor delay from disability. Age of attainment of each motor milestone may be compared with established norms by calculating a DQ. In Table 6. NEUROLOGIC EXAMINATION OF INFANTS AND TODDLERS WITH DEVELOPMENTAL DELAY
Classic Neurologic Examination Cranial nerves Deep tendon reflexes Tone (proximal, axial, and distal) Strength (proximal and distal) Cerebellar signs Extended Neurologic Examination (look at age of accomplishment or resolution, symmetry, and quality) Primitive reflexes (e.g., Moro, asymmetric tonic neck, tonic labyrinthine) Postural responses (e.g., neck righting, propping response) Neuromaturational examination/motor milestones
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examining a series of "mini DQs" the pediatrician can get a sense of the rate of progression of milestones and determine if there are specific problem areas or slowing of development. By coupling these findings with the neurologic examination (e.g., findings of hypertonia, hyperreflexia, or persistent primitive reflexes), the pediatrician can make the diagnosis of cerebral palsy or other motor dysfunction.
Developmental Screening Studies have demonstrated that pediatricians are unreliable in determining the presence of developmental delay by clinical judgment alone." 28 Yet despite the recommendation of routine developmental screening, studies have shown that few pediatricians use standardized instruments to detect developmental delay.42 As a consequence, almost half of children with mental retardation are not identified until after 3 years of age. 38 Hopefully, the recent emphasis on developmental and behavioral curricula in pediatric training programs will improve the pediatrician's skills in the use of standardized instruments and result in earlier identification of developmental disabilities. Pediatricians who do perform developmental screening have used many different techniques, including a review of developmental milestones with parents, performance of an informal collection orage-appropriate tasks, reliance on clinical judgment, and performance of all or part of formal screening standardized test(s) (Table 7).18 The most reasonable and effective method for developmental screening by the busy pediatrician is a combination of historical review of milestones (in comparison with established norms), observation of developmental skills using a standardized instrument, and the neurologic examination. When suspicion of developmental delay or disability is confirmed, the pediatrician may then pursue additional evaluations or refer the child for more comprehensive evaluation by a child development team. With the implementation of Part H of PL 99-457, specific standards for individual and comprehensive team evaluation must be established to determine eligibility for early intervention services of infants· and toddlers at risk for developmental delay. Pediatricians need to be trained to carry out these evaluations in a cost effective manner. The administration of a standardized screening instrument provides an opportunity for parents to express their concerns and for anticipatory guidance to take place. Tests designed for screening populations should have adequate sensitivity to identify individuals with a developmental disorder and sufficient specificity to avoid over-identification. Critics of routine developmental screening suggest that currently available screening instruments do not meet the conventional criteria for sensitivity or specificity.18 Table 7 lists some commonly used global and language-based developmental screening tests for infants and toddlers that can be administered in the pediatrician's office. These tools use parental interview or direct assessment. Children who are considered abnormal by the test norms or by the clinical judgment of the pediatrician should receive a more thorough diagnostic assessment. A pediatrician who suspects developmental delay may consult a variety of subspecialists who can assist in diagnosis and management. One such individual is the developmental pediatrician who can serve as a referral source for coordination of the assessment and management of the child at risk for developmental disability. In many metropolitan areas, coordinated interdisci-
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Table 7. DEVELOPMENTAL SCREENING INSTRUMENTS Description
Screening Tool GENERAL SCREENING TOOLS Batelle Developmental Inventory Screening test'l7 Denver 11'9, 20
Developmental Indicators for Assessment of Learning-Revised (DIAL-R)33
Infant Monitoring System 9
The Revised Developmental Screening Inventory (1980)27
LANGUAGE SCREENING TOOLS CLAMS (Clinical Linguistic Auditory Milestones Scale)'2 ELM (Early Language Milestone Scale)13
PPVT-R (Peabody Picture Vocabulary Test-Revised)"' 16, 31 REEL (Receptive-Expressive Emergent Language)'0
14
Screens multiple areas by combination of observation and history. Ages years. Global screening, including personal/social, fine motor/adaptive, gross motor skills, Scored as pass/fail/questionable, Ages 0-6 years. Screens fine and gross motor, expressive and receptive language, and cognitive/ academic skills by direct observation. Ages 2-6 years. Screening by parent report, assessing communication, gross and fine motor, adaptive and personal-social skills, Ages 0-36 months. Screens gross and fine motor, adaptive, problem-solving and language skills. Ages 0-3 years.
o-s
Assesses receptive and expressive language by observation and parental interview. Ages 1-36 months. Receptive and expressive language (pass/ fail) by interview, observation, and test administration. Ages 0-36 months. Single word receptive vocabulary. Ages 26 months to adult. Receptive and expressive language age, by parental interview. Ages 0-3 years,
plinary evaluations can be obtained though child development clinics, academic medical centers, and university affiliated programs. Upon completion of the evaluation, the child should be referred for intervention through the Division of Special Education. This can occur concurrently with other referrals for specific diagnosis through the health care system. MEDICAL TESTING
Does every child with developmental delay need a costly array of diagnostic procedures, including brain imaging studies, chromosomal karyotyping, metabolic screening, and electroencephalography (EEG)? Existing studies do not support the use of extensive ~esting of all children with developmental disabilities. 44 A careful history and physical examination with judicious use of consultants can help the clinician exercise prudence in the medical evaluation of the child with developmental disability. Some children need little or no medical testing as part of an evaluation for developmental delay; others require an extensive examination. Chromosomal Karyotyping
Karyotyping using peripheral blood leukocytes provides diagnostic information concerning chromosomal disorders. Children with a major anomaly or
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multiple minor anomalies compatible with known chromosomal syndromes should have karyotyping performed. A controversial issue is the determination of which persons with developmental disabilities should be tested for fragile X syndrome, the most common inherited disorder resulting in mental retardation. Fragile X syndrome produces one case of mental retardation in every 1000 to 1500 males. 48 In addition, one quarter to one third of heterozygous females have mental retardation. 23 Thus, it becomes a question of whether all children with mental retardation without a clear cause should be tested for fragile X syndrome. With the development of the less expensive DNA analysis for the fragile site of the X chromosome, it is likely that in the future fragile X will be tested for in increasing numbers of males with mental retardation40 and autism.'9
Electroencephalogram
In the general population the prevalence of seizure disorders is 0.5%. In individuals with developmental disabilities residing in residential facilities, the prevalence ranges from 12% to 58%.3 Seizures are not as common in children with less severe developmental disabilities. As in the population at large, generalized tonic-clonic seizures are the most frequent seizure type in children with developmental disabilities. There are specific epileptic syndromes, however, such as infantile spasms and Lennox-Gastaut syndrome, that are strongly associated with developmental disabilities. EEGs should be performed in any child who has a history of seizures or seizure-like episodes!S Yet, pediatricians who care for children with developmental disabilities are often asked to obtain EEGs to exclude ictal events as the cause of behavior dysfunction or lapses of attention. There is little evidence to support ictal events as a common cause of aggression, tantrums, or self-injurious behavior in these children. 2' Most of these behaviors are based on responses to the environment (see the article by Parrish elsewhere in this issue). Therefore, before attributing unusual behaviors to ictal events, a careful analysis of psychological and environmental variables needs to be performed. An advance in EEG technology that may aid in developmental diagnosis and in research into pathologic mechanisms of brain injury is brain electrical activity mapping (BEAM). This approach differs from conventional EEGs in the use of summation over time. Current research suggests that compared with a control population, differences exist in BEAM studies in individuals with learning disabilities, autism, and ADHD.15 Further research is necessary to determine if it has a role in routine clinical evaluation of children with these disorders.
Brain Imaging Studies
Computed tomography (CT) and magnetic resonance (MR) imaging have become routine tools in evaluating children with developmental disabilities. The question is, does every child with mental retardation or cerebral palsy really need a neuroimaging study? Computed tomography scans provide excellent resolution of intracranial structures with the ability to image bony structures and identify intracranial calcifications. To delineate grey versus white matter, injected contrast material is used. MR imaging scans make this differentiation and permit assessment of
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the development of normal myelinization without the need for contrast. MR imaging scans generally give a clearer picture of the brain than CT scans but do not accurately detect calcifications. Currently, CT studies require an individual to remain still for up to 20 to 30 minutes, whereas MR imaging studies can take twice as long. This means that young children and children with mental retardation usually require sedation. There are certain conditions or disorders associated with developmental disabilities in which the identification of intracranial pathology may be useful in diagnosis, genetic counseling, or determination of prognosis (Table 8), although it is unlikely to alter clinical management. 29, 36 For example, cortical atrophy represents a common but nonspecific finding in almost half of children with cerebral palsy46 and in about one quarter of children with mental retardation without known cause. 29, 36 Overall, neuroimaging studies are not routinely indicated as part of the medical evaluation for developmental disability. An unexpected change in behavior, head circumference, motor status, cognitive abilities, neurologic examination, or seizure frequency may indicate the need for a neuroimaging study, however.
Metabolic Screening It should be recognized that some metabolic screening is done routinely on all children in the newborn period. All states test for phenylketonuria and congenital hypothyroidism, and many states test for other inborn errors of metabolism including galactosemia, biotinidase deficiency, and maple syrup urine disease. Once a child has been diagnosed as having mental retardation, the question often arises concerning the need for additional metabolic investiTable 8. SPECIFIC DISORDERS AND NEUROIMAGING FINDINGS Disorder
Intrauterine infection Tuberous sclerosis Craniofacial anomalies Microcephaly
Genetic syndromes Aicardi's syndrome Sotos syndrome Smith-Lemli-Opitz Hypoxic-ischemic encephalopathy
Post central nervous system infection Intraventricular hemorrhage
Findings on Neuroimaging
Intracranial calcifications Periventricular tubers (may obstruct CSF flow and lead to hydrocephalus) Parenchymal abnormalities (e.g., holoprosencephaly, agenesis of corpus callosum, schizencephaly) Parenchymal abnormalities Intracranial calcifications (related to etiology for microcephaly) Atrophy Agenesis of corpus callosum Ventricular dilatation Severe parenchymal abnormalities Nonspecific findings: ventricular dilatation, atrophy Predisposing conditions to hypoxemia: structural parenchymal lesions (including holoprosencephaly, agenesis of corpus callosum, gyral abnormalities, schizencephaly) Nonspecific findings: ventricular dilatation, atrophy Specific lesions: infarcts, porencephaly Porencephaly Periventricular leukomalacia
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gation. This most commonly implies plasma amino acids, urine organic acids, and blood lactate. 39 Based on the extremely low prevalence of inborn errors, metabolic screening does not need to be a routine part of an evaluation. If there is a history of intermittent episodes of vomiting and lethargy, failure to thrive, progressive loss of skills or a plateau in milestone acquisition, an unusual body odor, or a suggestive family history, these studies should be performed. If there is significant concern about a metabolic disorder, it is probably best to refer the child to a metabolic specialist. COORDINATION OF CARE
Coordination of the many medical subspecialists and therapists providing services to a child with developmental disabilities is essential for optimal management. In addition to the pediatrician, the members of the interdisciplinary team may include a psychologist, speech and language therapist, occupational therapist, physical therapist, social worker, and special educator. Frequently consulted medical subspecialties include orthopedics, physiatry, genetics, ophthalmology, otolaryngology, child neurology, and child psychiatry. The information from diagnostic and etiologic evaluations outside the school system should be shared with the therapists and educational specialists who determine the child's eligibility for services or with the private therapist who provides care. Ongoing therapeutic services need to be monitored periodically to determine their effectiveness. If services are obtained from more than one source, that is, school and hospital or private therapists, there needs to be a dialogue between professionals so the child and family do not get conflicting advice. The pediatrician may be needed to determine the amount of intervention and to identify changes in medical status that may require alteration in services or reassessment. SUMMARY
With the recent mandate for early intervention services, the pediatrician is more involved than ever in the identification and evaluation of children with developmental disabilities. Developmental surveillance at routine visits and listening to parental concerns are crucial in the early diagnosis of developmental delay so that therapeutic interventions can be provided at a time when there is a good chance of decreasing disability and family stress. Medical evaluations and consultations must be prudent and based on a thorough history and physical. The pediatrician must have the knowledge and skills to coordinate medical care and to counsel and provide support to the child and family as they receive habilitative services and come to terms with the developmental diagnoses. References 1. Aisenberg RB, Rosenthal A, Nadas AS, et al: Developmental delay in infants with
congenital heart disease. Pediatr Cardiol 3:133, 1982 2. Alpeter T: Use of the PPVT-R for intellectual screening with a preschool pediatric sample. J Pediatr Psychol 10:195, 1985
d
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