Prospective and declarative memory problems following moderate and severe traumatic brain injury

PRIMARY OBJECTIVE: To examine prospective and declarative memory problems following moderate and severe traumatic brain injury (TBI) and the relationship between prospective memory (PM) and declarative memory and PM and other cognitive functions. RESEARCH DESIGN: The performance of persons who suffered a TBI (n = 25) was compared with that of a demographically matched control group (n = 25). METHODS AND PROCEDURES: Measures of time- and event-based PM, visual and verbal declarative memory, attention and executive functioning were administered to both groups. MAIN OUTCOME AND RESULTS: The group with a TBI performed more poorly on event- and time-based PM, verbal declarative memory, certain aspects of attention and executive functioning. The correlations between the measures of PM, declarative memory and the other cognitive tests were all non-significant. CONCLUSIONS: Problems with declarative memory, attention, and executive functioning do not adequately account for poorer PM performance following a TBI, suggesting that PM should also be assessed following TBI.     

Neuropsychological outcomes of traumatic brain injury and substance abuse in a New Zealand prison population

Fifty subjects with a history of traumatic brain injury TBI and or substance use, completed neuro psychological measures of short and long term verbal and visual memory, information processing, motor speed and co ordination, executive functioning, and malingering. All subjects performed below norms on tests of verbal memory and verbal abstract thinking, but overall no differences were found due to either severity of TBI or level of substance use. Maori subjects obtained the lowest scores on tests of verbal ability, but also reported higher rates of TBI and substance use, which is presumed to account for this result. In conclusion, prison populations seem to have disproportionately high rates of TBI, recurrent TBI, and substance use, compared to the general population. Further, there are a group of individuals who have experienced both TBI and substance abuse, with associated impairments in verbal memory and learning, abstract thinking, and who report problems with general memory and socialization. These difficulties may affect functioning both in prison and following release.     

Depression, cognition, and functional correlates of recovery outcome after traumatic brain injury

The present study investigated the prevalence and magnitude of depressive symptomatology in a sample of patients who had sustained traumatic brain injury (TBI) six months eariler. Depression was examined as a function of recovery outcome status, and its association with neuropsychological functioning, personal competency, and employability was also explored. Subjects were 100 patients who had previously sustained moderate-to-severe TBI who were enrolled as research subjects in the UCLA Brain Injury Reserch Center, and 30 matched control subjects who had sustained traumtic injuries other than to the head six months prior to evaluation. The results showed a significant association between depression and recovery status as measured by the Glasgow Outcome Scale (GOS). A significant majority of depressed subjects were found in the poorer GOS outcome groups (severe and moderate disability), compared to TBI subjects who had good GOS outcomes, and control subjects. This association was also reflected in the magnitude of the mean depression scores on two self report measures of depression. However, no association was found between depression status and performance on the neuropsychological measures. Effects of depression were found only on an examiner-rated Patient Competency scale, and a metacognition measure based on self-report. These results are discussed in terms of brain injury severity, recovery status, and metacognition issues in TBI and other disorders.     

A comparison of cognitive functioning in older adults with and without traumatic brain injury

OBJECTIVE: Cognitive impairments are common sequelae of traumatic brain injury (TBI) and are often associated with the natural process of aging. Few studies have examined the effect of both age and TBI on cognitive functioning. The purpose of this study was to compare cognitive functioning between older adults who sustained a TBI to an age-matched group of individuals without a brain injury and to determine whether the presence or absence of a genetic marker apolipoprotein epsilon (APOEepsilon4 allele) accounts for additional cognitive decline in both groups examined. METHODS AND PROCEDURES: Cognitive performance was measured by 11 neuropsychological tests, in 54 adults with TBI aged 55 and older and 40 age-matched control participants. All participants were reexamined 2 to 5 years later. SETTING: Community volunteer-based sample examined at a large, urban medical center. MAIN OUTCOME MEASURE(S): California Verbal Learning Test; Wechsler Memory Scale-III (Logical Memory I & II; Visual Reproduction I & II); Grooved Pegboard; Woodcock-Johnson Test of Cognitive Ability (Visual Matching and Cross-out); Wisconsin Card Sorting Test; Trail Making Test A & B; Conners' Continuous Performance Task; Wechsler Adult Intelligence Scale-III (Vocabulary); Controlled Oral Word Association Test; and Boston Naming Test. RESULTS: Participants with TBI had lower scores on tests of attention and verbal memory than did participants with no disability. Neither group exhibited a significant decline in cognitive function over time. The presence of the APOEepsilon4 allele did not account for additional decline in cognitive function in either group. CONCLUSION(S): The findings suggest that older adults with TBI may not be at increased risk for cognitive decline over short time periods (2 to 5 years) even if they are carriers of the APOEepsilon4 allele.     

The relationship between working memory, processing speed, verbal comprehension and FAS performance following traumatic brain injury

Primary objective: To investigate the relationship of working memory, processing speed and verbal comprehension with FAS performance in individuals who had sustained a traumatic brain injury (TBI).

Methods and procedure: Sixty-three patients with a TBI were grouped according to the presence of impaired verbal fluency performance and then compared on a number of cognitive and demographic variables.

Results: Following a TBI, working memory and processing speed had the greatest influence on verbal fluency performance. For those individuals who have not sustained a TBI, education, verbal intelligence, working memory and speed of information processing were related to FAS performance.

Conclusions: The findings of the study indicate that FAS performance was related to verbal intelligence, working memory ability, attention and speed of information processing. The results further suggest that different variables are related to FAS performance following a TBI as compared with control group performances.     

Mood disorders following traumatic brain injury: identifying the extent of the problem and the people at risk

The extent of mood disorders following traumatic brain injury (TBI), and the possible risk factors, are investigated. New data are presented from a prospective study of consecutive hospital admissions. Six months post-TBI, 99 adults completed a standardized assessment of emotional state, the Wimbledon Self-Report Scale. Cognitive performance and the impact of the injury on everyday functioning were also assessed. The rate of clinically significant mood disorders (caseness) was 38%. Of the demographic or injury characteristics, only pre-injury occupational status predicted post-injury caseness. Those unoccupied pre-injury were more likely to report mood disturbances post-injury. In contrast, post injury occupational status was not related to caseness either for the whole group or the subgroup of those previously occupied, despite the adverse effects on occupational functioning for a significant proportion of subjects. Associations were found between emotional state and cognitive and everyday functioning 6 months post-injury. Psychosocial disabilities appeared more strongly associated to mood disorders than did physical disabilities. A significant level of unmet need has been highlighted, and possible risk factors identified, which may inform the purchase and provision of TBI rehabilitation services. Follow-up data on these subjects are available and will be reported separately.     

Memory outcome at 5 years post-childhood traumatic brain injury

PRIMARY OBJECTIVE: This study seeks to extend previous findings by documenting memory performance in a sample of 70 children at 5 years post-injury. It was anticipated that increasing injury severity would be associated with decreased performance on working and complex memory tasks. It was also expected that injury severity would significantly predict memory, but that the time from insult to subsequent testing would be associated with an increased relationship to non-injury factors. RESEARCH DESIGN: Participants were assessed at 5 years post-injury, aged between 6-14 years, using measures of immediate, working and complex memory. METHODS AND PROCEDURES: The sample comprised 18 children who had sustained a severe TBI, 24 with a moderate TBI, 11 with a mild TBI and 17 healthy controls, matched for age, gender and socio-economic-status. RESULTS: Results indicated that severe TBI was associated with decreased complex auditory-verbal memory performance, although children with TBI did not display impairment on immediate, working or complex visual-spatial memory. While injury severity significantly predicted complex memory outcome, non-injury factors failed to significantly predict either working or complex memory performance. CONCLUSIONS: Future research should be engineered towards further clarifying what influences recovery from childhood TBI in the elongated post-injury period.     

Association between posttraumatic stress, depression, and functional impairments in adolescents 24 months after traumatic brain injury

The degree to which postinjury posttraumatic stress disorder (PTSD) and/or depressive symptoms in adolescents are associated with cognitive and functional impairments at 12 and 24 months after traumatic brain injury (TBI) is not yet known. The current study used a prospective cohort design, with baseline assessment and 3-, 12-, and 24-month followup, and recruited a cohort of 228 adolescents ages 14-17 years who sustained either a TBI (n = 189) or an isolated arm injury (n = 39). Linear mixed-effects regression was used to assess differences in depressive and PTSD symptoms between TBI and arm-injured patients and to assess the association between 3-month PTSD and depressive symptoms and cognitive and functional outcomes. Results indicated that patients who sustained a mild TBI without intracranial hemorrhage reported significantly worse PTSD (Hedges g = 0.49, p = .01; Model R(2) = .38) symptoms across time as compared to the arm injured control group. Greater levels of PTSD symptoms were associated with poorer school (η(2) = .07, p = .03; Model R(2) = .36) and physical (η(2) = .11, p = .01; Model R(2) = .23) functioning, whereas greater depressive symptoms were associated with poorer school (η(2) = .06, p = .05; Model R(2) = .39) functioning.     

Self-awareness of prospective memory failure in adults with traumatic brain injury

The frequency of prospective memory failure in individuals with severe traumatic brain injury (TBI) was investigated by comparison with a non-brain-injured control group. Self-awareness of prospective memory function was also assessed by comparing self-ratings with ratings by significant others. Study participants included 33 individuals with severe TBI and 29 non-brain-injured persons. Each participant nominated a close friend or relative who completed the informant's version of the questionnaire. Participants and their significant others both rated the participants' frequency of prospective memory lapses using the Comprehensive Assessment of Prospective Memory (CAPM). An independent groups design was adopted to compare the TBI and control groups. No significant difference was found between the TBI and control participants' self-ratings of frequency of prospective memory failure, but ratings by significant others were significantly different. The TBI group demonstrated less self-awareness (i.e. underestimated the frequency of prospective memory failure compared to significant others) than the control group.     

Age effects on long-term neuropsychological outcome in paediatric traumatic brain injury

In order to investigate the relationship between age at injury and long-term neuropsychological impairment, 29 children and adolescents who sustained traumatic brain injury (TBI) were studied at least 6 years post-trauma. Tests of intellectual, memory, visuospatial and frontal lobe functions were administered to patients and 29 normal matched control subjects. Correlations between performance on neuropsychological tests and age showed the following direction: the younger the child when TBI was sustained, the worse the cognitive outcome. After controlling for injury severity, visuospatial functions remained related to age. Patients' performance differed significantly from that of controls in half of the neuropsychological variables analysed. To further investigate the effects of age at injury, the sample was divided in two groups (TBI before and after age of 8) and then compared with their respective controls. Patients damaged earlier presented impaired intellectual and visuospatial functions. The results suggest that neuropsychological sequelae remain after at least 6 years of evolution, and that there is an age at injury effect.     

Neurocognitive fitness in the sub-acute stage after mild TBI: the effect of age

Objective: Age is assumed to be a negative prognostic factor in recovery from moderate-to-severe traumatic brain injury (TBI). Little is known on cognitive performance after mild TBI in relation to age in the sub-acute stage after injury.

Method: Ninety-nine mild TBI subjects (age 15-75) were compared with 91 healthy control subjects (age 14-74) in a case-control design. Patients were matched on age, sex and level of education, with control subjects. Mean interval between injury and cognitive assessment was 13 days. Neurocognitive test battery contained tests of verbal memory, selective attention, general speed of information processing and verbal fluency.

Results: An overall effect was found of a single mild TBI on neurocognitive performance in the sub-acute stage after injury. Age did not add significantly to the effect of mild TBI on cognitive functioning.

Conclusion: Patients suffering from mild TBI are characterized by subtle neurocognitive deficits in the weeks directly following the trauma. The notion that elderly subjects have a worse outcome in the sub-acute period after mild TBI is at least not in line with the results of this study.     

Memory outcome at 5 years post-childhood traumatic brain injury

Primary objective: This study seeks to extend previous findings by documenting memory performance in a sample of 70 children at 5 years post-injury. It was anticipated that increasing injury severity would be associated with decreased performance on working and complex memory tasks. It was also expected that injury severity would significantly predict memory, but that the time from insult to subsequent testing would be associated with an increased relationship to non-injury factors.

Research design: Participants were assessed at 5 years post-injury, aged between 6-14 years, using measures of immediate, working and complex memory.

Methods and procedures: The sample comprised 18 children who had sustained a severe TBI, 24 with a moderate TBI, 11 with a mild TBI and 17 healthy controls, matched for age, gender and socio-economic-status.

Results: Results indicated that severe TBI was associated with decreased complex auditory-verbal memory performance, although children with TBI did not display impairment on immediate, working or complex visual-spatial memory. While injury severity significantly predicted complex memory outcome, non-injury factors failed to significantly predict either working or complex memory performance.

Conclusions: Future research should be engineered towards further clarifying what influences recovery from childhood TBI in the elongated post-injury period.     

The effects of traumatic brain injury on the predicted and actual performance of a test of prospective remembering

PRIMARY OBJECTIVE: The aim of the present study was to assess prospective memory (PM) with a video-based task using naturalistic stimuli, in a group with long-term disabilities resulting from traumatic brain injury (TBI). The specific focus of the research was on comparing the accuracy of the TBI and control groups' estimates of successful completion of the prospective memory tasks. RESEARCH DESIGN: A group of 25 persons with TBI and 20 matched controls were compared on the video-based test of prospective remembering, on a test of retrospective memory (the Logical Memory sub-test of the Wechsler Memory Scale) and tests of executive dysfunction. Correlations between the neuropsychological and PM test scores were calculated and an item analysis of the PM test was undertaken. PROCEDURES: For the PM test, participants were given a scenario involving a robbery, and a list of tasks to be completed in a nearby city centre. The instructions were given twice and on the second occasion they were asked to rate the likelihood of remembering each item. They then watched a videotaped segment showing the perspective of a person first driving and then walking through an unfamiliar city. Their task was to recall each instruction when a relevant cue appeared. OUTCOMES AND RESULTS: The TBI group ratings of likelihood of recalling items were entirely equivalent to those made by the controls. On the PM test, however, their performance was significantly reduced. The performance of the TBI group on the PM test was correlated with scores on the Logical Memory and verbal fluency measures. CONCLUSIONS: The results showed that, although the TBI group performed more poorly on the PM task, their expectations about how much they would remember were comparable to those of the controls. The findings suggest that persons with TBI may have unrealistic expectations about how much they will remember in a novel situation. Awareness and acceptance of cognitive changes after TBI can be a significant issue for rehabilitation.     

Personal digital assistants as cognitive aids for individuals with severe traumatic brain injury: a community-based trial

OBJECTIVE: The purpose of this study was to examine the efficacy of personal digital assistants (PDAs) as cognitive aids in a sample of individuals with severe traumatic brain injury (TBI). METHOD: The group included 23 community-dwelling individuals at least 1 year post-severe TBI, who had difficulties in performing everyday tasks due to behavioural memory problems. Participants were trained by an occupational therapist to use PDAs as cognitive aids and assessed for occupational performance (using Canadian Occupational Performance Measure (COPM)) and participation in everyday life tasks (using Craig Handicap Assessment and Rating Technique-Revised (CHART)) before training and 8 weeks after training concluded. RESULTS: Statistically significant improvement was noted for self-ratings of occupational performance and satisfaction with occupational performance (COPM); significant improvement in a self-rating of participation was noted (CHART-R). CONCLUSION: A brief training intervention utilizing PDAs as cognitive aids is associated with improved self-ratings of performance in everyday life tasks among community-dwelling individuals with severe TBI.     

Neurobehavioral functioning and magnetic resonance imaging findings in young boxers

In a prospective investigation of neurobehavioral functioning in young boxers, 13 pugilists and 13 matched control subjects underwent tests of attention, information-processing rate, memory, and visuomotor coordination and speed. The results disclosed more proficient verbal learning in the control subjects, whereas delayed recall and other measurements of memory did not differ between the two groups. Reaction time was faster in the boxers than in the control subjects, but no other differences were significant. Ten subjects in each group were retested 6 months later and exhibited improvement in their neuropsychological performance as compared to baseline measurements. However, there were no differences in scores between the boxers and the control subjects at the follow-up examination or in the magnitude of improvement from baseline values. Magnetic resonance imaging, which was performed in nine of the boxers, disclosed normal findings.     

Health care costs associated with traumatic brain injury and psychiatric illness in adults

A cohort design was used to determine the contribution of traumatic brain injury (TBI) and psychiatric illness to health care costs for adolescents and adults in the 3 years following mild or moderate-to-severe TBI compared to a matched cohort without TBI, controlling for confounders. In all, 3756 subjects 15 years or older from a large health maintenance organization database were examined. We identified subjects who sustained a TBI in 1993 (n=939) and selected three control subjects per TBI-exposed subject (n=2817), matched for age, sex, and enrollment at the time of injury. Unadjusted mean costs in 2009-adjusted dollars were compared using Kruskal-Wallis tests and Mann-Whitney U tests, and adjusted mean costs were compared using gamma regression analyses. Average costs were 76% higher in the 3 years after injury for the mild TBI group, and 5.75 times greater for the moderate-to-severe TBI group compared to controls. The presence of psychiatric illness was associated with more than doubling of total costs for both inpatient and outpatient non-mental health care. Gamma regression analyses confirmed significantly higher costs in patients with TBI or psychiatric illness. A significant interaction between moderate-to-severe TBI and psychiatric illness indicated a 3.39 times greater cost among patients with both exposures compared with those exposed to moderate-to-severe TBI without psychiatric illness. TBI and psychiatric illness were each associated with significant increases in health care costs; those with the combination of moderate-to-severe TBI and psychiatric illness had much higher costs than any other group.     

Memory remediation in long-term acquired brain injury: two approaches in diary training

This study investigated the remediation and assessment of everyday memory impairment in a sample of long-term acquired brain injury (ABI) subjects. The Rivermead Behavioural Memory Test (RBMT) and subtests of the Wechsler Memory Scale-Revised (WMS-R) were selected to measure global memory performance. A memory questionnaire and a daily memory checklist were developed from a review of existing self-report questionnaires. The interrelationships among self-report measures and standardized psychometric tests of memory were examined and the findings suggest that selfreport measures may be used to obtain relatively accurate information about everyday memory performance. A baseline across groups' design evaluated the relative effectiveness of two different approaches in training subjects to use a diary to compensate for memory problems. There was a Diary Only (DO) approach, which emphasized compensation based upon task specific learning, and a Diary and Self-Instructional Training (DSIT) approach, which taught compensation using higher cognitive skills of self-awarenes and self-regulation. The results obtained show that, during the treatment phase, the DSIT group more consistently made diary entries, reported less memory problems, and made more positive ratings associated with treatment efficacy. The implications arising from the current study are that: (1) the choice of memory assessment procedures need to be guided by the patients' real daily living needs; and (2) an approach based upon self-instructional training has greater ecological validity than an approach that focuses on task specific learning. In general, successful assessment and rehabilitation of memory deficits requires a well-established theoretical basis and sound ecological validity.     

Recovery in memory function in the first year following TBI in children

Primary objective : To examine memory skills, at acute, 6- and 12-monthly stages, following childhood traumatic brain injury (TBI).

Research design : Prospective, longitudinal, between-group design, comparing pre-injury and postinjury intellectual and memory measures, across three levels of injury severity.

Methods and procedures : Investigation of memory skills in a group of 76 children who had sustained a mild, moderate or severe TBI. Specific tests were used to measure immediate and short-term memory, and more complex multi-trial learning.

Main outcomes and results : The severe TBI group exhibited greater deficits on memory tasks, irrespective of modality, in the acute, 6- and 12-month post-injury stages, in comparison to mild and moderate TBI groups. Performance was dependent on both injury severity and task demands.

Conclusions : Memory difficulties are present during the acute, 6- and 12-months following childhood TBI. With a clearer understanding of the memory deficits following TBI, appropriate strategies can be taught and interventions implemented for these children.     

Assessing subtle memory impairments in the everyday memory performance of brain injured people: exploring the potential of the extended Rivermead Behavioural Memory Test

A substantial number of brain injured patients complain of memory deficits, despite achieving scores within the normal range on tests of memory functioning. The Rivermead Behavioural Memory Test is an ecologically valid test used to assess everyday memory problems. This test is effective at detecting moderate-to-severe impairments, yet subtle memory deficits may go undetected for some patients who achieve a score within the normal range. The initial development of an extended version of this test (RBMT-E), designed to detect subtle decrements in memory performance, has recently been described. The performance of 16 brain injured patients was assessed on both the RBMT and the RBMT-E. The performance of these patients on the RBMT-E was compared with that of matched controls. Overall, the patients performed significantly worse than the controls, and showed particular difficulty in two subtests involving recalling a route and remembering to deliver a message. Those patients who scored in the 'normal' range on the RBMT could be further differentiated on the basis of their RBMT-E scores into 'good', 'average' and 'poor' performance categories. The patients' performance was not significantly associated with general intellectual ability. These results suggest that the RBMT-E may be a useful clinical tool to aid therapists in the assessment of subtle impairments of everyday memory performance following brain injury.     

Interview study of the effects of paediatric traumatic brain injury on memory

Primary objective: To investigate the effects of traumatic brain injury (TBI) on children's day-to-day memory functioning. Research design: A qualitative, interview-based procedure. Methods and procedures: Thirteen parents of children and adolescents with TBI were interviewed for 2 hours. Data from 12 of the interviews were analysed using content analysis, which involved transcribing notes, sorting information into categories, identifying similarities or differences among the categories and isolating meaningful trends. Main outcomes and results: Over half of the children experienced explicit (past recall) and prospective memory (future intentions) loss, but few experienced implicit memory (e.g. procedural) loss. Further, parents utilized their own interventions in minimizing their children's memory disabilities. Conclusion: Memory loss is common and can impact on everyday living, but is selective in the types of memory affected. Follow-ups are recommended to assess quantitatively, the so-far, little-known effects of paediatric TBI on prospective memory and to examine more closely parent interventions to assess their wider applicability in TBI rehabilitation.