- Email: [email protected]
Memory deficits
Handbook of Clinical Neurology, Vol. 110 (3rd series) Neurological Rehabilitation M.P. Barnes and D.C. Good, Editors # 2013 Elsevier B.V. All rights reserved
Chapter 30
Memory deficits BARBARA A. WILSON* The Oliver Zangwill Centre, Princess of Wales Hospital, Cambs, UK
INTRODUCTION Memory problems are one of the commonest consequences of an insult to the brain (Hawley et al., 2004). A number of conditions can result in impaired memory but most people seen for rehabilitation are likely to have sustained a traumatic brain injury (TBI), stroke, encephalitis, or hypoxic brain damage. Those with progressive conditions, particularly Alzheimer disease (AD), are increasingly offered rehabilitation to help with their difficulties (Clare, 2008). Although at present there is no effective way to restore lost memory functioning, we can help people to compensate for their problems and to learn more efficiently. For those with very severe and widespread cognitive difficulties it may be that the best we can do is to modify or structure or rearrange the environment to help them manage without a memory. A few of those referred for memory rehabilitation will have the pure amnesic syndrome, the characteristics of which are (a) a profound difficulty in learning and remembering most kinds of new information (anterograde amnesia), (b) difficulty remembering some information acquired before the onset of the syndrome (retrograde amnesia), (c) normal immediate memory as measured by forward digit span, (d) normal/nearly normal learning on implicit tasks, and (e) normal/nearly normal functioning on other cognitive tasks (Baddeley, 2004). These patients may well be able to compensate without too much trouble because, apart from memory, their cognitive skills are intact (see Wilson, 1999, for a report of rehabilitation for patients with the pure amnesic syndrome). The majority of patients, however, will have more widespread problems; in addition to their memory difficulties they are likely to have attention and concentration difficulties, slowed thinking and information processing, poor planning and
organizational deficits, and possibly word-finding problems. For both those with a pure amnesia and those with additional problems, however, the main characteristics are: 1. 2.
Immediate memory is normal or nearly normal There is difficulty remembering after a delay or distraction 3. Patients have difficulty learning most new information 4. Events that happened some time before the insult are typically remembered better than those that happened a short time before. Although some patients will have other kinds of memory deficit such as impaired semantic memory (loss of general knowledge) or impaired immediate memory, these are rare and not representative of those seen for rehabilitation. Wilson (2009) discusses the ways in which memory can be classified and ways in which it can break down: memory can be conceptualized in terms of timedependent memory, information-dependent memory, modality-specific memory, stages in remembering, recall or recognition, explicit and implicit memory, and retrograde or anterograde memory. The typical person referred for memory rehabilitation is young and most likely to be a male who has sustained a TBI. In addition to memory, he presents with attention, planning, and organizational difficulties. He is also likely to have emotional problems such as anxiety, depression, and mood swings. He may have behavior problems such as poor self-control and verbal aggression. He wants to return to work or has returned and failed. His family needs help and, after a few months, the young man’s friends start to drift away leaving him socially isolated. All of these problems should be addressed in rehabilitation.
*Correspondence to: Professor Barbara A. Wilson, O.B.E., Ph.D., D.Sc., C.Psychol, F.B.Ps.S., F.med.S.C., Ac.S.S., The Oliver Zangwill Centre, Princess of Wales Hospital, Lynn Rd., Ely, Cambs, CB6 1DN, UK. E-mail: [email protected]
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GENERAL PRINCIPLES FOR HELPING PEOPLE WITH MEMORY DEFICITS Memory can be defined as the ability to take in, store, and retrieve information. The taking in of information is the encoding stage; retaining the information is the storage stage; and accessing the information when it is required is the retrieval stage. There are guidelines we can follow to help with all these stages (Wilson, 2009). To improve encoding, first simplify the information to be remembered as it is easier to remember short words than long words and short sentences than long sentences even if the words and sentences are well understood by the person trying to remember (Wilson, 1989). Second, the person should be asked to remember only one thing at a time so do not present three or four items, words, names, or instructions one after the other. Third, make sure the person has understood the information being presented. This is usually achieved by having him or her say it back in his or her own words. Fourth, ask the person to link the information to something already known; for example, when remembering a name think of someone else with the same name or a word that rhymes with the name. Fifth, follow the little and often rule, otherwise known as distributed practice. When people are trying to learn something they learn better when the practice trials are spread over a period of time rather than crowded all together (Baddeley, 1992). Sixth, avoid trial-and-error learning. In order to benefit from our mistakes we need to be able to remember them. For people who cannot remember their errors, the very fact of making an incorrect response may strengthen that erroneous response so we want to avoid mistakes occurring in the first place (Baddeley and Wilson, 1994). Seventh, ensure that the people who are trying to remember or learn are not passive recipients of the information. They need to think about the material or information and manipulate it in some way. This is also known as “levels of processing” after Craik and Lockhart (1972). Storage is the next stage; once information is registered in memory it needs to be stored there until required. Once information is encoded and has entered the long-term store, rehearsal, practice, or testing can help keep it there. One way to do this is to use the principle of expanded rehearsal, otherwise known as spaced retrieval (Landauer and Bjork, 1978). This involves testing the person immediately after he or she has seen or heard a short piece of new information such as a new telephone number or name or short address; then test again after a very short delay, maybe of 2 or 3 seconds, and again after a slightly longer delay. The retention interval is gradually built up and can lead to better retention of information. This principle, therefore, can help both encoding and storage. The third stage in the memory process is to retrieve information when it is needed. Retrieval problems are
experienced by everyone at times but are even more likely for those with memory problems. If we can provide a “hook” in the form of a cue or prompt, we may be able to help them access the correct memory. Providing the first letter of a name may well lead to the person remembering the whole name. The principle of “context specificity” should also be borne in mind. It has been shown that recall is easier if the retrieval situation is similar to the original learning situation (Godden and Baddeley, 1975). So memory-impaired people may remember better if they are in the same room and with the same people as they were when the learning first occurred. Obviously, in most situations, we want to avoid such context specificity so when trying to teach a person with memory impairments new information; we should teach that person to remember in a number of different settings and social situations. Our aim should be to encourage learning in many different, everyday situations that are likely to be encountered in daily life. Learning should not be limited to one particular context such as a hospital ward, classroom, or therapist’s office.
MODIFYING THE ENVIRONMENT FOR THOSE WITH SEVERE AND WIDESPREAD COGNITIVE DEFICITS Kapur et al. (2004) classify nonelectronic aids into environmental and portable external aids.
Environmental aids External aids that are not specific to a particular environment, such as notebooks, clocks, or computers, are considered later. Norman (1988) argues that knowledge should be in the world rather than in the head. By this he means that if we approach a door it should be obvious whether or not we should push or pull to open the door. If we are using a cooker it should be obvious which knob works which burner. We should not have to remember these things as the design should make it obvious. This is the same principle behind the concept of environmental memory aids. Just as people with severe physical disabilities can use environmental control systems to enable them to open and close doors, turn the pages of a book, answer the telephone, and so forth, so can people with cognitive deficits avoid the need to use memory provided the environment is structured in a certain way. Thus, someone with severe executive deficits may be able to function in a structured environment, with no distractions and where there is no need to problem-solve as the task at hand is clear and unambiguous. Similarly, people with severe memory problems may not be handicapped in environments where there are no demands made on memory. Thus if doors, cupboards, drawers, and storage jars
MEMORY DEFICITS are clearly labeled, if rooms are cleared of dangerous equipment, and if someone appears to remind or accompany the memory-impaired person when it is time to go to the dentist or to eat supper, the person may cope reasonably well. Kapur et al. (2004) give other examples. Items can be left by the front door for people who forget to take belongings with them when they leave the house; a message can be left on the mirror in the hallway; and a simple flow chart can be used to help people search in likely places when they cannot find a lost belonging (Moffat, 1989). Cars, mobile phones, and other items may have intrinsic alarms to remind people to do things. These can be paired with voice messages to remind people why the alarm is ringing. Modifications can also be made to verbal environments to avoid irritating behavior such as the repetition of a question, story, or joke. It might be possible to identify a “trigger” or an antecedent that elicits this behavior. Thus, by eliminating the “trigger” one can avoid the repetitious behavior. For example, in response to the question “How are you today?,” one young brain-injured man would say “Just getting over my hangover.” If staff simply said “Good morning”, however, he replied “Good morning,” so the repetitious comments about his supposed hangover were avoided. Environmental aids involve the immediate environment, which requires the structuring and organization of equipment or material to reduce the load on memory, and the wider environment, which involves the layout of buildings, shopping centers, streets, and towns. Smart Houses are already in existence to help “disable the disabling environment” described by Wilson and Evans (2000). Layouts of shopping centers, office buildings, hospitals, and residential homes differ in the ease of getting around. In some the sign posting, color coding, alarm systems, and warning signs are excellent in reducing the chances of getting lost or falling downstairs. We can reduce the load on memory through improvements in the organization of these wider environments.
NEW LEARNING FOR MEMORYIMPAIRED PEOPLE The inability to learn new information is one of the most handicapping aspects of memory impairment and much of rehabilitation is concerned with this issue. Mnemonics, the method of vanishing cues, spaced retrieval, and errorless learning are the main ways we can enhance new learning in those with memory deficits. Mnemonics are systems that enable us to remember things more easily and usually refer to internal strategies such as reciting a rhyme to remember how many days there are in a month or remembering the order of the colors of the rainbow through a sentence such as “Richard of York
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gives battle in vain “whereby the first letter of each word is the first letter of the color (red, orange, yellow, green, blue, indigo, violet). Although verbal and visual mnemonic systems have been used successfully with memory-impaired people (Wilson, 2009), not everyone can use them. Instead of expecting memory-impaired people to use mnemonics spontaneously, therapists may need to employ them to help their patients achieve faster learning for particular pieces of information, such as names of a few people or a new address. It may help to use two or three strategies. New information should be taught one step at a time, individual preferences and styles should be acknowledged, and we should focus on things that the person with memory impairments wants and needs to learn and will be useful in his or her everyday life. Finally, generalization or the transfer to real life must be built in to the training program. Rote rehearsal, or simply repeating material, is widely used by the general population but it is not a particularly good learning strategy for people with memory deficits. We can hear or read something many times over and still not remember it and the information may simply “go in one ear and out the other.” Other strategies are better at enhancing learning (Ehlhardt et al., 2008). One is the method of vanishing cues (VC) whereby prompts are provided and then gradually faded out. For example, someone learning a new name might be expected first to copy the whole name, then the last letter would be deleted; the name would be copied again and the last letter inserted by the memory-impaired person, then the last two letters would be deleted and the process repeated until all letters were completed by the memory-impaired person. Glisky et al. (1986) were the first to report this method with memory-impaired people. Several studies have since been published with both nonprogressive patients and those with dementia (see Wilson, 2009, for a full discussion). The results are mixed. Another method to improve learning is spaced retrieval, also known as expanded or expanding rehearsal (Landauer and Bjork, 1978). This method involves the presentation of material to be remembered, followed by immediate testing, then a very gradual lengthening of the retention interval. Spaced retrieval may work because it is a form of distributed practice, i.e., distributing the learning trials over a period of time rather than massing them together in one block. Distributed practice is known to be more effective than massed practice (Baddeley, 1999). The method has been used to help people with TBI, stroke, encephalitis, and dementia. In order to benefit from our mistakes, such as occurs with trial-and-error learning, we need to be able to remember our mistakes and, of course, memoryimpaired people have difficulty with this, so the very fact of making an erroneous response can strengthen that
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response. This is the rationale behind errorless learning, which is a teaching technique whereby the likelihood of mistakes during learning is minimized as far as possible. Errors can be avoided through the provision of spoken or written instructions or guiding someone through a particular task or modeling the steps of a procedure little by little. There is now considerable evidence that errorless learning is superior to trial-and-error learning for people with severe memory deficits. In a meta-analysis of errorless learning, Kessels and De Haan (2003) found a large and statistically significant effect size of this kind of learning for those with severe memory deficits. The combination of errorless learning and spaced retrieval would appear to be a powerful learning strategy for people with progressive conditions in addition to those with nonprogressive conditions (Wilson, 2009). Ehlhardt et al. (2008) provides guidelines for teaching new information to memory-impaired people: 1. 2. 3. 4. 5.
6. 7.
Intervention targets should be clearly delineated; Errors should be constrained; Sufficient practice should be provided; Practice should be distributed; Multiple examples should be provided to avoid hyperspecificity of learning and enhance generalization; Strategies to promote more effortful processing should be used; and New learning should focus on personally meaningful targets.
COMPENSATORY EXTERNAL MEMORYAIDS External memory aids may provide cues to alert someone to the fact that something needs to be done at a particular time and place, or they may act as systems to store information independent of a particular temporal or spatial context. Alarms, timers, and pagers to help people to remember to take medication or take a cake out of the oven belong in the former category, while journals and tape recorders belong in the latter category. Although external memory aids may well be the most efficient strategies for memory-impaired people, it is not always easy for them to use such aids. The use of such aids involves memory, so the people who need them most typically have greatest difficulty learning to use such aids. Nonelectronic aids are more widely used than electronic ones (Evans et al., 2003) with wall calendars/wall charts, notebooks, lists of things to do, and appointment diaries being the top four strategies reported in the Evans et al. (2003) study. This study, together with an earlier one by Wilson (1991), found that certain characteristics predicted which memory-impaired people were more likely to use external aids, including: age (younger
people more likely than older ones); severity of deficit (very severely memory-impaired people compensate less well); premorbid use of aids which increased the likelihood of use postmorbidly; and those without widespread cognitive deficits were more likely to use aids than those with such deficits. Scherer (2005) pointed out that, in order to use external aids successfully, there needs to be insight and motivation, past use of memory aids, certain cognitive, emotional, and motivational characteristics, demands on memory, support from family, school, or work, and availability of appropriate aids. A number of studies have looked at the efficacy of external aids for memory-impaired people and these are summarized in Wilson (2009). In Cambridge in 2003, Kapur (reported in Wilson and Kapur, 2009) set up the first Memory Aids Clinic in the UK, and possibly in the world. In collaboration with Kopelman and Dewar, Kapur set up a second clinic in London in 2006. Wilson and Kapur (2009) provide a description of how to set up a memory aids clinic or resource center including funding, staffing, the range of aids and resources needed, finding and cataloging these aids, and research and development.
EMOTIONAL CONSEQUENCES OF MEMORY IMPAIRMENT Emotional problems are common after brain injury (Fleminger et al., 2003; Horner et al., 2008). In addition to their memory problems, many memory-impaired people will have additional cognitive deficits such as impaired attention, word-finding problems, and difficulties with planning, judgment, and reasoning, and they will also suffer emotional disorders such as anxiety, depression, mood swings, anger, or fear. When neuropsychological rehabilitation programs address the cognitive, emotional, and psychosocial consequences of brain injury, patients experience less emotional distress, increased self-esteem, and greater productivity (Prigatano et al., 1994; Prigatano, 1999). Treatment for emotional difficulties includes psychological support for individuals and for groups (Wilson et al., 2009). Individual psychological support is mostly derived from cognitive behavioral therapy (CBT) which is now very much part of neuropsychological rehabilitation programs, particularly in the UK (Gracey et al., 2009). Tyerman and King (2004) provide suggestions on how to adapt psychotherapy and CBT for those with memory problems. Notes, audio- and videotapes of sessions, frequent repetitions, mini reviews, telephone reminders to complete homework tasks, and use of family members as co-therapists can all be used to help circumvent the difficulties posed by impaired retention of the therapeutic procedures.
MEMORY DEFICITS 361 Group therapy can also be of great help in reducing the person receiving rehabilitation wants to do, someanxiety and other emotional difficulties. Memorything that is relevant and meaningful to him or her, impaired people often benefit from interaction with and something reflecting his or her longer-term aims. others having similar problems. Those who fear they Rehabilitation should address personally meaningful are losing their sanity may have their fears allayed themes, activities, settings, and interactions (Ylvisaker through the observation of others with similar problems. and Feeney, 2000), so we should not set goals that lack meaning for the patient such as “improve performance Groups can reduce anxiety and distress; they can instill on a memory test.” Nor should we set goals that are hope and show patients that they are not alone; it may vague, such as “improve memory functioning,” or highly be easier to accept advice from peers than from theraunlikely to be achievable, such as “restore memory funcpists, or easier to use strategies that peers are using tioning.” Goals should be set after discussion with the rather than strategies recommended by professional patient, family members, carers, and, if necessary, other staff (Evans, 2009; Malley et al., 2009). relevant support services. We need to know what the families and the brain-injured person perceive as their PLANNING A MEMORY problems, what are their priorities and needs, and what REHABILITATION PROGRAM do they want to be able to do? Goals need to be negotiThe first step in devising a memory rehabilitation program ated with all concerned. If patients have an unrealistic goal such as “I want my memory back to how it was bewill be the clinical interview. We need as much background fore” then we need to try to persuade them that this is information as possible. Have the memory problems ocprobably not possible but we might (for example) be able curred as a result of an illness or infection, or have they to help them remember what they have to do each day, developed slowly over time? What problems are most trouand how would they feel about trying this as a goal first? bling for the patient and the family? What coping strategies The wording of the goals should be comfortable for paare they using? What memory aids, if any, are being employed? What does the patient and the family expect tients and should allow them to feel they have ownership to happen as a result of rehabilitation? Are these expectaof the goal. Goals should follow the SMART principles. SMART is an acronym that stands for Specific, Measurtions realistic or not? Is any recovery likely to occur? able, Achievable, Realistic, and Time based. An example At the end of the clinical interview we may want to ofof a SMART memory goal might be for “Jill to remember fer patients and families some general advice on the nature to take her medication twice a day without prompts from of memory, for example that some aspects will be unafher carers; at the end of 6 weeks she will achieve this at fected, together with information on what environmental least 75 per cent of the time.” This is specific; it is measuror situational factors might affect memory. Drugs and alcohol, for example, are likely to impair memory functionable as we can count how many times Jill does this before ing, so too will anxiety, depression, poor sleep, and fatigue; we begin treatment; we believe it is potentially achievable; it is a realistic step in Jill’s long-term goal of being indemany people may demand too much of themselves and pendent; and we have specified a time frame by which this need to reduce their expectations. Kapur (2008) offers tips should be achieved. The first short-term goal might be to to help people cope. These include taking it easy, being organized, concentrating better, and using memory aids. provide a pager for Jill and see if she can respond to a test At some point a detailed assessment should take message; this might be followed by giving her a checklist place. This should include a formal neuropsychological to complete when she carries out the test message; Jill’s assessment of all cognitive abilities including memory occupational therapist will observe Jill to make sure she in order to build up a picture of a person’s cognitive completes the checklist accurately and so forth. Jill will strengths and weaknesses. In addition, assessment of probably be working on other goals at the same time emotional and psychosocial functioning should be carand these may well be other memory goals, other cogniried out. Standardized tests should be complemented tive goals, emotional goals, leisure goals, and so on. with observations, interviews, and self-report measures. Selecting the best strategy to achieve the goal is This will allow a proper formulation of the situation. A another consideration. For prospective memory tasks formulation uses theories and models to understand the such as remembering to take medication, water the development and maintenance of problems and can be plants, or feed the dog, external aids are the method used to make predictions about treatment. If other team of choice. If we wish to teach new information we need members, say, occupational and speech and language to consider spaced retrieval, vanishing cues, rehearsal therapists, have assessed the patient then a team discusstrategies, and mnemonics, and follow errorless learning sion and joint formulation is desirable. principles. The next stage in the memory rehabilitation program Finally, we need to evaluate the success of our treatis likely to be the goal-setting stage. A goal is something ment programs not only at a group level but also at an
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individual level. For every patient we see, we want to know whether or not the patient is changing and, if so, is the change due to our intervention or would it have happened anyway? One way to do this is through singlecase experimental designs which allow us to separate the effects of treatment from the effects of spontaneous recovery (Barlow et al., 2008).
CONCLUSIONS Memory rehabilitation can help people to compensate for, bypass, or reduce their everyday problems and thus survive more efficiently in their own most appropriate environments. Rehabilitation makes clinical and economic sense and should be widely available to all those who need it.
REFERENCES Baddeley AD (1992). Memory theory and memory therapy. In: BA Wilson, N Moffat (Eds.), Clinical Management of Memory Problems. 2nd edn. Nelson Thornes, Cheltenham, pp. 1–31. Baddeley AD (1999). Essentials of Human Memory. Psychology Press, Hove. Baddeley AD (2004). The psychology of memory. In: AD Baddeley, MD Kopelman, BA Wilson (Eds.), The Essential Handbook of Memory Disorders for Clinicians. John Wiley & Sons, Chichester, pp. 1–15. Baddeley AD, Wilson BA (1994). When implicit learning fails: Amnesia and the problem of error elimination. Neuropsychologia 32: 53–68. Barlow DH, Nock MK, Hersen M (2008). Single Case Experimental Designs: Strategies for Studying Behavior Change. 3rd edn. Allyn & Bacon, New York. Clare L (2008). Neuropsychological Rehabilitation and People with Dementia. 1st edn. Psychology Press, Hove. Craik FIM, Lockhart RS (1972). Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior 11: 671–684. Ehlhardt L, Sohlberg MM, Kennedy M et al. (2008). Evidence-based practice guidelines for instructing individuals with neurogenic memory impairments: what have we learned in the past 20 years? Neuropsychol Rehabil 18: 300–342. Evans JJ (2009). The cognitive group, part 2: memory. In: BA Wilson, F Gracey, JJ Evans, A Bateman (Eds.), Neuropsychological Rehabilitation: Theory, Models, Therapy and Outcome. Cambridge University Press, Cambridge, pp. 98–111. Evans JJ, Wilson BA, Needham P et al. (2003). Who makes good use of memory aids? Results of a survey of people with acquired brain injury. J Int Neuropsychol Soc 9: 925–935. Fleminger S, Oliver DL, Williams WH et al. (2003). The neuropsychiatry of depression after brain injury. Neuropsychol Rehabil 13: 65–87.
Glisky EL, Schacter DL, Tulving E (1986). Computer learning by memory-impaired patients: acquisition and retention of complex knowledge. Neuropsychologia 24: 313–328. Godden DR, Baddeley AD (1975). Context-dependent memory in two natural environments: on land and underwater. Br J Psychol 66: 335–331. Gracey F, Yeates G, Palmer S, Psaila K (2009). The psychological support group. In: BA Wilson, F Gracey, JJ Evans, A Bateman (Eds.), Neuropsychological Rehabilitation: Theory, Models, Therapy and Outcome. Cambridge University Press, Cambridge, pp. 123–137. Hawley CA, Ward AB, Magnay A et al. (2004). Outcomes following head injury: a population study. J Neurol Neurosurg Psychiatry 75: 737–742. Horner MD, Selassie AW, Lineberry L et al. (2008). Predictors of psychological symptoms 1 year after traumatic brain injury: a population-based, epidemiological study. J Head Trauma Rehabil 23: 74–83. Kapur N, Glisky GL, Wilson BA (2004). Technological memory aids for people with memory deficits. Neuropsychol Rehabil 14: 41–60. Kapur N (2008). Cambridge Memory Manual: A manual for improving everyday memory skills. Addenbrooke’s Hospital, Cambridge, UK. Kessels RPC, de Haan EHF (2003). Implicit learning in memory rehabilitation: a meta-analysis on errorless learning and vanishing cues methods. J Clin Exp Neuropsychol 25: 805–814. Landauer TK, Bjork RA (1978). Optimum rehearsal patterns and name learning. In: MM Gruneberg, P Morris, RN Sykes (Eds.), Practical Aspects of Memory. Academic Press, London, pp. 625–632. Malley D, Bateman A, Gracey F (2009). Practically based project groups. In: BA Wilson, F Gracey, JJ Evans, A Bateman (Eds.), Neuropsychological Rehabilitation: Theory, Models, Therapy and Outcome. Cambridge University Press, Cambridge, pp. 164–180. Moffat N (1989). Home-based cognitive rehabilitation with the elderly. In: LW Poon, DC Rubin, BA Wilson (Eds.), Everyday cognition in adulthood and late life. Cambridge University Press, Cambridge, pp. 659–680. Norman DA (1988). The Psychology of Everyday Things. Basic Books, New York. Prigatano GP (1999). Principles of Neuropsychological Rehabilitation. Oxford University Press, New York. Prigatano GP, Klonoff PS, O’Brien KP et al. (1994). Productivity after neuropsychologically oriented milieu rehabilitation. J Head Trauma Rehabil 9: 91–102. Scherer M (2005). Assessing the benefits of using assistive technologies and other supports for thinking, remembering and learning. Disabil Rehabil 27: 731–739. Tyerman A, King N (2004). Interventions for psychological problems after brain injury. In: LH Goldstein, JE McNeil (Eds.), Clinical Neuropsychology: A Practical Guide to Assessment and Management for Clinicians. John Wiley & Sons, Chichester, pp. 385–404. Wilson BA (1989). Improving recall of health service information. Clin Rehabil 3: 275–279.
MEMORY DEFICITS Wilson BA (1991). Long term prognosis of patients with severe memory disorders. Neuropsychol Rehabil 1: 117–134. Wilson BA (1999). Case Studies in Neuropsychological Rehabilitation. Oxford University Press, New York. Wilson BA (2009). Memory Rehabilitation: Integrating Theory and Practice. Guilford Press, New York. Wilson BA, Evans JJ (2000). Practical management of memory problems. In: GE Berrios, JR Hodges (Eds.), Memory Disorders in Psychiatric Practice. Cambridge University Press, Cambridge, pp. 291–311.
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Wilson BA, Kapur N (2009). Compensating for memory deficits with memory aids. In: BA Wilson (Ed.), Memory Rehabilitation: Integrating Theory and Practice. Guilford Press, New York, pp. 52–73. Wilson BA, Gracey F, Evans JJ et al. (Eds.), (2009). Neuropsychological Rehabilitation: Theory, Therapy and Outcomes. Cambridge University Press, Cambridge. Ylvisaker M, Feeney T (2000). Reconstruction of identity after brain injury. Brain Impairment 1: 12–28.
Chapter 30
Memory deficits BARBARA A. WILSON* The Oliver Zangwill Centre, Princess of Wales Hospital, Cambs, UK
INTRODUCTION Memory problems are one of the commonest consequences of an insult to the brain (Hawley et al., 2004). A number of conditions can result in impaired memory but most people seen for rehabilitation are likely to have sustained a traumatic brain injury (TBI), stroke, encephalitis, or hypoxic brain damage. Those with progressive conditions, particularly Alzheimer disease (AD), are increasingly offered rehabilitation to help with their difficulties (Clare, 2008). Although at present there is no effective way to restore lost memory functioning, we can help people to compensate for their problems and to learn more efficiently. For those with very severe and widespread cognitive difficulties it may be that the best we can do is to modify or structure or rearrange the environment to help them manage without a memory. A few of those referred for memory rehabilitation will have the pure amnesic syndrome, the characteristics of which are (a) a profound difficulty in learning and remembering most kinds of new information (anterograde amnesia), (b) difficulty remembering some information acquired before the onset of the syndrome (retrograde amnesia), (c) normal immediate memory as measured by forward digit span, (d) normal/nearly normal learning on implicit tasks, and (e) normal/nearly normal functioning on other cognitive tasks (Baddeley, 2004). These patients may well be able to compensate without too much trouble because, apart from memory, their cognitive skills are intact (see Wilson, 1999, for a report of rehabilitation for patients with the pure amnesic syndrome). The majority of patients, however, will have more widespread problems; in addition to their memory difficulties they are likely to have attention and concentration difficulties, slowed thinking and information processing, poor planning and
organizational deficits, and possibly word-finding problems. For both those with a pure amnesia and those with additional problems, however, the main characteristics are: 1. 2.
Immediate memory is normal or nearly normal There is difficulty remembering after a delay or distraction 3. Patients have difficulty learning most new information 4. Events that happened some time before the insult are typically remembered better than those that happened a short time before. Although some patients will have other kinds of memory deficit such as impaired semantic memory (loss of general knowledge) or impaired immediate memory, these are rare and not representative of those seen for rehabilitation. Wilson (2009) discusses the ways in which memory can be classified and ways in which it can break down: memory can be conceptualized in terms of timedependent memory, information-dependent memory, modality-specific memory, stages in remembering, recall or recognition, explicit and implicit memory, and retrograde or anterograde memory. The typical person referred for memory rehabilitation is young and most likely to be a male who has sustained a TBI. In addition to memory, he presents with attention, planning, and organizational difficulties. He is also likely to have emotional problems such as anxiety, depression, and mood swings. He may have behavior problems such as poor self-control and verbal aggression. He wants to return to work or has returned and failed. His family needs help and, after a few months, the young man’s friends start to drift away leaving him socially isolated. All of these problems should be addressed in rehabilitation.
*Correspondence to: Professor Barbara A. Wilson, O.B.E., Ph.D., D.Sc., C.Psychol, F.B.Ps.S., F.med.S.C., Ac.S.S., The Oliver Zangwill Centre, Princess of Wales Hospital, Lynn Rd., Ely, Cambs, CB6 1DN, UK. E-mail: [email protected]
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GENERAL PRINCIPLES FOR HELPING PEOPLE WITH MEMORY DEFICITS Memory can be defined as the ability to take in, store, and retrieve information. The taking in of information is the encoding stage; retaining the information is the storage stage; and accessing the information when it is required is the retrieval stage. There are guidelines we can follow to help with all these stages (Wilson, 2009). To improve encoding, first simplify the information to be remembered as it is easier to remember short words than long words and short sentences than long sentences even if the words and sentences are well understood by the person trying to remember (Wilson, 1989). Second, the person should be asked to remember only one thing at a time so do not present three or four items, words, names, or instructions one after the other. Third, make sure the person has understood the information being presented. This is usually achieved by having him or her say it back in his or her own words. Fourth, ask the person to link the information to something already known; for example, when remembering a name think of someone else with the same name or a word that rhymes with the name. Fifth, follow the little and often rule, otherwise known as distributed practice. When people are trying to learn something they learn better when the practice trials are spread over a period of time rather than crowded all together (Baddeley, 1992). Sixth, avoid trial-and-error learning. In order to benefit from our mistakes we need to be able to remember them. For people who cannot remember their errors, the very fact of making an incorrect response may strengthen that erroneous response so we want to avoid mistakes occurring in the first place (Baddeley and Wilson, 1994). Seventh, ensure that the people who are trying to remember or learn are not passive recipients of the information. They need to think about the material or information and manipulate it in some way. This is also known as “levels of processing” after Craik and Lockhart (1972). Storage is the next stage; once information is registered in memory it needs to be stored there until required. Once information is encoded and has entered the long-term store, rehearsal, practice, or testing can help keep it there. One way to do this is to use the principle of expanded rehearsal, otherwise known as spaced retrieval (Landauer and Bjork, 1978). This involves testing the person immediately after he or she has seen or heard a short piece of new information such as a new telephone number or name or short address; then test again after a very short delay, maybe of 2 or 3 seconds, and again after a slightly longer delay. The retention interval is gradually built up and can lead to better retention of information. This principle, therefore, can help both encoding and storage. The third stage in the memory process is to retrieve information when it is needed. Retrieval problems are
experienced by everyone at times but are even more likely for those with memory problems. If we can provide a “hook” in the form of a cue or prompt, we may be able to help them access the correct memory. Providing the first letter of a name may well lead to the person remembering the whole name. The principle of “context specificity” should also be borne in mind. It has been shown that recall is easier if the retrieval situation is similar to the original learning situation (Godden and Baddeley, 1975). So memory-impaired people may remember better if they are in the same room and with the same people as they were when the learning first occurred. Obviously, in most situations, we want to avoid such context specificity so when trying to teach a person with memory impairments new information; we should teach that person to remember in a number of different settings and social situations. Our aim should be to encourage learning in many different, everyday situations that are likely to be encountered in daily life. Learning should not be limited to one particular context such as a hospital ward, classroom, or therapist’s office.
MODIFYING THE ENVIRONMENT FOR THOSE WITH SEVERE AND WIDESPREAD COGNITIVE DEFICITS Kapur et al. (2004) classify nonelectronic aids into environmental and portable external aids.
Environmental aids External aids that are not specific to a particular environment, such as notebooks, clocks, or computers, are considered later. Norman (1988) argues that knowledge should be in the world rather than in the head. By this he means that if we approach a door it should be obvious whether or not we should push or pull to open the door. If we are using a cooker it should be obvious which knob works which burner. We should not have to remember these things as the design should make it obvious. This is the same principle behind the concept of environmental memory aids. Just as people with severe physical disabilities can use environmental control systems to enable them to open and close doors, turn the pages of a book, answer the telephone, and so forth, so can people with cognitive deficits avoid the need to use memory provided the environment is structured in a certain way. Thus, someone with severe executive deficits may be able to function in a structured environment, with no distractions and where there is no need to problem-solve as the task at hand is clear and unambiguous. Similarly, people with severe memory problems may not be handicapped in environments where there are no demands made on memory. Thus if doors, cupboards, drawers, and storage jars
MEMORY DEFICITS are clearly labeled, if rooms are cleared of dangerous equipment, and if someone appears to remind or accompany the memory-impaired person when it is time to go to the dentist or to eat supper, the person may cope reasonably well. Kapur et al. (2004) give other examples. Items can be left by the front door for people who forget to take belongings with them when they leave the house; a message can be left on the mirror in the hallway; and a simple flow chart can be used to help people search in likely places when they cannot find a lost belonging (Moffat, 1989). Cars, mobile phones, and other items may have intrinsic alarms to remind people to do things. These can be paired with voice messages to remind people why the alarm is ringing. Modifications can also be made to verbal environments to avoid irritating behavior such as the repetition of a question, story, or joke. It might be possible to identify a “trigger” or an antecedent that elicits this behavior. Thus, by eliminating the “trigger” one can avoid the repetitious behavior. For example, in response to the question “How are you today?,” one young brain-injured man would say “Just getting over my hangover.” If staff simply said “Good morning”, however, he replied “Good morning,” so the repetitious comments about his supposed hangover were avoided. Environmental aids involve the immediate environment, which requires the structuring and organization of equipment or material to reduce the load on memory, and the wider environment, which involves the layout of buildings, shopping centers, streets, and towns. Smart Houses are already in existence to help “disable the disabling environment” described by Wilson and Evans (2000). Layouts of shopping centers, office buildings, hospitals, and residential homes differ in the ease of getting around. In some the sign posting, color coding, alarm systems, and warning signs are excellent in reducing the chances of getting lost or falling downstairs. We can reduce the load on memory through improvements in the organization of these wider environments.
NEW LEARNING FOR MEMORYIMPAIRED PEOPLE The inability to learn new information is one of the most handicapping aspects of memory impairment and much of rehabilitation is concerned with this issue. Mnemonics, the method of vanishing cues, spaced retrieval, and errorless learning are the main ways we can enhance new learning in those with memory deficits. Mnemonics are systems that enable us to remember things more easily and usually refer to internal strategies such as reciting a rhyme to remember how many days there are in a month or remembering the order of the colors of the rainbow through a sentence such as “Richard of York
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gives battle in vain “whereby the first letter of each word is the first letter of the color (red, orange, yellow, green, blue, indigo, violet). Although verbal and visual mnemonic systems have been used successfully with memory-impaired people (Wilson, 2009), not everyone can use them. Instead of expecting memory-impaired people to use mnemonics spontaneously, therapists may need to employ them to help their patients achieve faster learning for particular pieces of information, such as names of a few people or a new address. It may help to use two or three strategies. New information should be taught one step at a time, individual preferences and styles should be acknowledged, and we should focus on things that the person with memory impairments wants and needs to learn and will be useful in his or her everyday life. Finally, generalization or the transfer to real life must be built in to the training program. Rote rehearsal, or simply repeating material, is widely used by the general population but it is not a particularly good learning strategy for people with memory deficits. We can hear or read something many times over and still not remember it and the information may simply “go in one ear and out the other.” Other strategies are better at enhancing learning (Ehlhardt et al., 2008). One is the method of vanishing cues (VC) whereby prompts are provided and then gradually faded out. For example, someone learning a new name might be expected first to copy the whole name, then the last letter would be deleted; the name would be copied again and the last letter inserted by the memory-impaired person, then the last two letters would be deleted and the process repeated until all letters were completed by the memory-impaired person. Glisky et al. (1986) were the first to report this method with memory-impaired people. Several studies have since been published with both nonprogressive patients and those with dementia (see Wilson, 2009, for a full discussion). The results are mixed. Another method to improve learning is spaced retrieval, also known as expanded or expanding rehearsal (Landauer and Bjork, 1978). This method involves the presentation of material to be remembered, followed by immediate testing, then a very gradual lengthening of the retention interval. Spaced retrieval may work because it is a form of distributed practice, i.e., distributing the learning trials over a period of time rather than massing them together in one block. Distributed practice is known to be more effective than massed practice (Baddeley, 1999). The method has been used to help people with TBI, stroke, encephalitis, and dementia. In order to benefit from our mistakes, such as occurs with trial-and-error learning, we need to be able to remember our mistakes and, of course, memoryimpaired people have difficulty with this, so the very fact of making an erroneous response can strengthen that
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response. This is the rationale behind errorless learning, which is a teaching technique whereby the likelihood of mistakes during learning is minimized as far as possible. Errors can be avoided through the provision of spoken or written instructions or guiding someone through a particular task or modeling the steps of a procedure little by little. There is now considerable evidence that errorless learning is superior to trial-and-error learning for people with severe memory deficits. In a meta-analysis of errorless learning, Kessels and De Haan (2003) found a large and statistically significant effect size of this kind of learning for those with severe memory deficits. The combination of errorless learning and spaced retrieval would appear to be a powerful learning strategy for people with progressive conditions in addition to those with nonprogressive conditions (Wilson, 2009). Ehlhardt et al. (2008) provides guidelines for teaching new information to memory-impaired people: 1. 2. 3. 4. 5.
6. 7.
Intervention targets should be clearly delineated; Errors should be constrained; Sufficient practice should be provided; Practice should be distributed; Multiple examples should be provided to avoid hyperspecificity of learning and enhance generalization; Strategies to promote more effortful processing should be used; and New learning should focus on personally meaningful targets.
COMPENSATORY EXTERNAL MEMORYAIDS External memory aids may provide cues to alert someone to the fact that something needs to be done at a particular time and place, or they may act as systems to store information independent of a particular temporal or spatial context. Alarms, timers, and pagers to help people to remember to take medication or take a cake out of the oven belong in the former category, while journals and tape recorders belong in the latter category. Although external memory aids may well be the most efficient strategies for memory-impaired people, it is not always easy for them to use such aids. The use of such aids involves memory, so the people who need them most typically have greatest difficulty learning to use such aids. Nonelectronic aids are more widely used than electronic ones (Evans et al., 2003) with wall calendars/wall charts, notebooks, lists of things to do, and appointment diaries being the top four strategies reported in the Evans et al. (2003) study. This study, together with an earlier one by Wilson (1991), found that certain characteristics predicted which memory-impaired people were more likely to use external aids, including: age (younger
people more likely than older ones); severity of deficit (very severely memory-impaired people compensate less well); premorbid use of aids which increased the likelihood of use postmorbidly; and those without widespread cognitive deficits were more likely to use aids than those with such deficits. Scherer (2005) pointed out that, in order to use external aids successfully, there needs to be insight and motivation, past use of memory aids, certain cognitive, emotional, and motivational characteristics, demands on memory, support from family, school, or work, and availability of appropriate aids. A number of studies have looked at the efficacy of external aids for memory-impaired people and these are summarized in Wilson (2009). In Cambridge in 2003, Kapur (reported in Wilson and Kapur, 2009) set up the first Memory Aids Clinic in the UK, and possibly in the world. In collaboration with Kopelman and Dewar, Kapur set up a second clinic in London in 2006. Wilson and Kapur (2009) provide a description of how to set up a memory aids clinic or resource center including funding, staffing, the range of aids and resources needed, finding and cataloging these aids, and research and development.
EMOTIONAL CONSEQUENCES OF MEMORY IMPAIRMENT Emotional problems are common after brain injury (Fleminger et al., 2003; Horner et al., 2008). In addition to their memory problems, many memory-impaired people will have additional cognitive deficits such as impaired attention, word-finding problems, and difficulties with planning, judgment, and reasoning, and they will also suffer emotional disorders such as anxiety, depression, mood swings, anger, or fear. When neuropsychological rehabilitation programs address the cognitive, emotional, and psychosocial consequences of brain injury, patients experience less emotional distress, increased self-esteem, and greater productivity (Prigatano et al., 1994; Prigatano, 1999). Treatment for emotional difficulties includes psychological support for individuals and for groups (Wilson et al., 2009). Individual psychological support is mostly derived from cognitive behavioral therapy (CBT) which is now very much part of neuropsychological rehabilitation programs, particularly in the UK (Gracey et al., 2009). Tyerman and King (2004) provide suggestions on how to adapt psychotherapy and CBT for those with memory problems. Notes, audio- and videotapes of sessions, frequent repetitions, mini reviews, telephone reminders to complete homework tasks, and use of family members as co-therapists can all be used to help circumvent the difficulties posed by impaired retention of the therapeutic procedures.
MEMORY DEFICITS 361 Group therapy can also be of great help in reducing the person receiving rehabilitation wants to do, someanxiety and other emotional difficulties. Memorything that is relevant and meaningful to him or her, impaired people often benefit from interaction with and something reflecting his or her longer-term aims. others having similar problems. Those who fear they Rehabilitation should address personally meaningful are losing their sanity may have their fears allayed themes, activities, settings, and interactions (Ylvisaker through the observation of others with similar problems. and Feeney, 2000), so we should not set goals that lack meaning for the patient such as “improve performance Groups can reduce anxiety and distress; they can instill on a memory test.” Nor should we set goals that are hope and show patients that they are not alone; it may vague, such as “improve memory functioning,” or highly be easier to accept advice from peers than from theraunlikely to be achievable, such as “restore memory funcpists, or easier to use strategies that peers are using tioning.” Goals should be set after discussion with the rather than strategies recommended by professional patient, family members, carers, and, if necessary, other staff (Evans, 2009; Malley et al., 2009). relevant support services. We need to know what the families and the brain-injured person perceive as their PLANNING A MEMORY problems, what are their priorities and needs, and what REHABILITATION PROGRAM do they want to be able to do? Goals need to be negotiThe first step in devising a memory rehabilitation program ated with all concerned. If patients have an unrealistic goal such as “I want my memory back to how it was bewill be the clinical interview. We need as much background fore” then we need to try to persuade them that this is information as possible. Have the memory problems ocprobably not possible but we might (for example) be able curred as a result of an illness or infection, or have they to help them remember what they have to do each day, developed slowly over time? What problems are most trouand how would they feel about trying this as a goal first? bling for the patient and the family? What coping strategies The wording of the goals should be comfortable for paare they using? What memory aids, if any, are being employed? What does the patient and the family expect tients and should allow them to feel they have ownership to happen as a result of rehabilitation? Are these expectaof the goal. Goals should follow the SMART principles. SMART is an acronym that stands for Specific, Measurtions realistic or not? Is any recovery likely to occur? able, Achievable, Realistic, and Time based. An example At the end of the clinical interview we may want to ofof a SMART memory goal might be for “Jill to remember fer patients and families some general advice on the nature to take her medication twice a day without prompts from of memory, for example that some aspects will be unafher carers; at the end of 6 weeks she will achieve this at fected, together with information on what environmental least 75 per cent of the time.” This is specific; it is measuror situational factors might affect memory. Drugs and alcohol, for example, are likely to impair memory functionable as we can count how many times Jill does this before ing, so too will anxiety, depression, poor sleep, and fatigue; we begin treatment; we believe it is potentially achievable; it is a realistic step in Jill’s long-term goal of being indemany people may demand too much of themselves and pendent; and we have specified a time frame by which this need to reduce their expectations. Kapur (2008) offers tips should be achieved. The first short-term goal might be to to help people cope. These include taking it easy, being organized, concentrating better, and using memory aids. provide a pager for Jill and see if she can respond to a test At some point a detailed assessment should take message; this might be followed by giving her a checklist place. This should include a formal neuropsychological to complete when she carries out the test message; Jill’s assessment of all cognitive abilities including memory occupational therapist will observe Jill to make sure she in order to build up a picture of a person’s cognitive completes the checklist accurately and so forth. Jill will strengths and weaknesses. In addition, assessment of probably be working on other goals at the same time emotional and psychosocial functioning should be carand these may well be other memory goals, other cogniried out. Standardized tests should be complemented tive goals, emotional goals, leisure goals, and so on. with observations, interviews, and self-report measures. Selecting the best strategy to achieve the goal is This will allow a proper formulation of the situation. A another consideration. For prospective memory tasks formulation uses theories and models to understand the such as remembering to take medication, water the development and maintenance of problems and can be plants, or feed the dog, external aids are the method used to make predictions about treatment. If other team of choice. If we wish to teach new information we need members, say, occupational and speech and language to consider spaced retrieval, vanishing cues, rehearsal therapists, have assessed the patient then a team discusstrategies, and mnemonics, and follow errorless learning sion and joint formulation is desirable. principles. The next stage in the memory rehabilitation program Finally, we need to evaluate the success of our treatis likely to be the goal-setting stage. A goal is something ment programs not only at a group level but also at an
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individual level. For every patient we see, we want to know whether or not the patient is changing and, if so, is the change due to our intervention or would it have happened anyway? One way to do this is through singlecase experimental designs which allow us to separate the effects of treatment from the effects of spontaneous recovery (Barlow et al., 2008).
CONCLUSIONS Memory rehabilitation can help people to compensate for, bypass, or reduce their everyday problems and thus survive more efficiently in their own most appropriate environments. Rehabilitation makes clinical and economic sense and should be widely available to all those who need it.
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