Problems in measuring cognitive recovery after acute brain injury

Evolution of the cognitive profile in school-aged patients with severe TBI during the first 2 years of neurorehabilitation

OBJECTIVE

Persistent post-injury cognitive, academic and behavioural deficits have been documented in children who sustained severe TBI during the school-age years. The major aim of this study was to examine and follow-up for 2 years the cognitive profile of a sample of post-injured patients (aged 6-16.11), in order to verify to what extent they recovered their intellectual functions after rehabilitation.

METHOD

Twenty-six patients who received a specific neuropsychological treatment and three cognitive evaluations with WISC-III were selected from a pool of 77.

RESULTS

This group of patients showed a mild cognitive deficit at baseline, which improved over the 2 years to a borderline level. Despite the improvement in intellectual quotients and single sub-test scores achieved through rehabilitation, different recovery times were seen according to the function under study. The most common deficits are in processing speed, inferential and lexical-semantic skills.

CONCLUSIONS

Detailed analysis of the WISC-III sub-tests allows for an accurate description of single cognitive functions after TBI. This allows one to make differential diagnoses between functional profiles and plan individualized rehabilitation treatments. Post-injured school-aged patients should receive rehabilitation for a period of at least 2 years, which is the time necessary for an at-least partial reorganization of basic cognitive functions.

Brief assessment of severe language impairments: Initial validation of the Mississippi aphasia screening test

PRIMARY OBJECTIVE

To validate the Mississippi Aphasia Screening Test (MAST) which includes nine sub-scales measuring expressive and receptive language abilities.

RESEARCH DESIGN

Evaluation of inpatients admitted to neurology, neurosurgery or rehabilitation units at two local hospitals and who were within 60 days of onset of a unilateral ischemic or haemorrhagic stroke (left hemisphere (LH; n=38); right hemisphere (RH; n=20)). Additional participants were recruited from the community to comprise a non-patient control sample (NP; n=36).

METHODS

Data collection included administration of the MAST and chart review.

RESULTS

The LH group showed more impairment than the RH and NP groups on summary scores. The LH group performed worse than the NP group on all sub-scales. The object recognition and verbal fluency sub-scales did not discriminate the stroke groups.

CONCLUSION

Analyses suggest good criterion validity for the MAST in differentiating communication impairments among clinical and control samples.

Long-term physical impairment and functional outcomes after complex facial fractures

To develop an understanding of the expected functional outcomes after facial trauma, a retrospective cohort study of patients with complex facial fractures was conducted. A cohort of adults aged 18 to 55 years who were admitted to the R. Adams Cowley Shock Trauma Center between July of 1986 and July of 1994 for treatment of a Le Fort midface fracture (resulting from blunt force) was retrospectively identified. Outcomes of interest included measures of general health status and psychosocial well being in addition to self-reported somatic symptoms. General health status was ascertained using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). The Body Satisfaction Scale was used to define patient concerns about altered body image and shape. To determine whether complex maxillofacial trauma and facial fractures contributed to altered social interactions, the Social Avoidance and Distress scale was used. In addition, information about a patient, his or her injury, and its treatment were ascertained from the medical records. Using the methods described above, 265 patients with Le Fort fractures were identified. These individuals were matched to a similar group of 242 general injury patients. A total of 190 of the Le Fort patients (72 percent of those eligible for the study) and 144 (60 percent) general injury patients were successfully located, and long-term interview data were acquired.Le Fort fracture patients as a group had similar health status outcomes when compared with the group of general injury patients. However, when outcomes were examined by the complexity of the Le Fort fracture, the authors found that study subjects with severe, comminuted Le Fort injuries (group D) had significantly lower SF-36 scores (worse outcomes) for the two dimensions related to role limitations: role limitations due to physical problems and role limitations due to emotional problems (p < 0.05). SF-36 scores for all other dimensions except physical function were also lower for comminuted versus less complex Le Fort fractures, although differences were not statistically significant.Specifically, there was a direct relationship between severity of facial injury and patients reporting work disability. Of group C and D Le Fort patients (severely comminuted fractures) only 55 and 58 percent, respectively, had returned to work at the time of follow-up interview. These figures are significantly lower than the back-to-work percentage of patients with less severe facial injury (70 percent). When study participants were asked if they were experiencing specific somatic symptoms at the time of the interview that they had not experienced before the injury, a significantly larger percent of the Le Fort fracture patients (compared with the general injury patients) responded in the affirmative. Differences between the Le Fort fracture and general injury groups were statistically significant (p < 0.05) for all 11 symptoms. The percentage of patients reporting complaints increased with increasing complexity of facial fracture in the areas of visual problems, alterations in smell, difficulty with mastication, difficulty with breathing, and epiphora, and these differences reached statistical significance. Patients sustaining comminuted Le Fort facial fractures report poorer health outcomes than patients with less severe facial injury and substantially worse outcomes than population norms. It is also this severely injured population that reports the greatest percentage of injury-related disability, preventing employment at long-term follow-up. The long-term goal of centralized tertiary trauma treatment centers must be to return the patient to a productive, active lifestyle.

Disability and handicap 5 years after a head injury: a population-based study

A population-based cohort of 407 head trauma patients has been studied since 1986 to estimate the prevalence of long-term disabilities and handicaps by means of a structured questionnaire. Five years later, 6-1 patients were deceased and 36 were lost to follow-up. Prevalence of subjective and behavioral complaints was high whatever the initial head trauma severity. Lethality in severe head injuries was 56%, and half of the survivors remained disabled. In minor and moderate head injured patients, most disabilities were related to extracranial injuries. Taking all disabilities into consideration, each year 24 per 100,000 patients of such a population are likely to suffer from at least one long-lasting disability, including 10 per 100,000 whose disabilities are due to extracranial injuries. Head injuries induce long-lasting handicap in 9 per 100,000 habitants which is severe in 2 per 100,000. These figures point to the need of reinforcing preventive actions and long-term care of these patients.

Head injury and sexual dysfunction

An extensive review of the head injury and human sexuality literature was completed, to augment an understanding of the impact of traumatic head injury on sexual functioning. Despite clinical evidence that sexual dysfunction after head injury is prevalent and of great import, sexual concerns have been neglected in much of the post-traumatic head injury and rehabilitation literature. Characteristics of head injury concerning cerebral physiology, post-traumatic sequelae, and the effects on sexual functioning are examined. Rehabilitation and family/spouse literature was also examined for information on sexuality. The majority of this article reviews research on sexual sequelae after head injury, such as impulsiveness/inappropriateness, changes in libido and sexual frequency, global sexual difficulties, and specific sexual dysfunctions. Treatment models for the sexual problems after head injury are also reviewed and found to be limited in number. Treatment issues and suggestions are addressed. This article provides information about the sexual problems of head-injured patients to facilitate the development of diagnostic and intervention programmes.

Post-traumatic apallic syndrome following head injury. Part 2: Treatment

There is no doubt that vegetative patients need the appropriate medical and nursing procedures as well as family involvement, education and counselling. Additional structured stimulation programmes are used for the treatment of coma and vegetative state. The theoretical foundation is derived from animal studies. The relevance of the results for the rehabilitation of head-injured human patients remains questionable, because all animal studies involve the use of cerebral lesions different from those found in human head-injured patients. The studies of human sensory stimulation give more an orientation than a definitive statement. Very recently, hypotheses concerning sensory regulation have begun to be evaluated. Further investigations are required to provide a more definite conclusion.

Post-concussion syndrome and the coping hypothesis

Neuropsychological functioning and level of subjective symptomatology was assessed in 15 adults at 2 weeks, 1 month, and 3 months post-concussion. Performance by the concussion subjects was compared to the results obtained by a matched group of normal controls. At 2 weeks post-injury the concussion subjects had deficits in intellectual, attentional, memory, and language abilities. Visuospatial constructional abilities were relatively preserved. Concussed subjects also reported high levels of disturbance in affective, cognitive, and social functioning. By 3 months post-injury the concussed subjects were still displaying deficits in attentional and language functioning. The level of subjective symptoms reported by the concussed subjects was not significantly different from that reported by controls. Results provide some support for the 'coping hypothesis' explanation of post-concussion syndrome.

Post-coma disturbance and post-traumatic amnesia as nonlinear predictors of cognitive outcome following severe closed head injury: findings from the Westmead Head Injury Project

This study sought to identify combinations of early neurological variables which best predict cognitive outcome 12 months after severe head injury. At the time of admission patients were assessed on seven neurological indices. Twelve months later a battery of neuropsychological tests examining recent memory functioning and speed of information processing was administered. Recent memory functioning was best predicted by a combination of post-coma disturbance (PCD; i.e. the duration of post-traumatic amnesia, PTA, minus the duration of coma) and presence of subarachnoid haemorrhage (multiple r = 0.54, p < 0.001). Speed of information processing was best predicted by the duration of PTA (r = 0.35, p < 0.01). However, these conclusions were based on square root transformation of PCD and PTA variables. The success of this transformation in assisting prediction confirms suggestions that the relationship between PTA and cognitive outcome is nonlinear.

Encephalopathy and neuropathy in end-stage liver disease before and after liver transplantation

The nervous system involvement of 8 patients with end-stage liver disease was evaluated by means of clinical neurological, neuropsychological, neurophysiological and neuroradiological investigation before and 6-12 months after a successful liver transplantation. Preoperatively, all subjects (7 women, 1 man; mean age 40 years, range 30-54 years) exhibited decreased muscle strength and 2 patients manifested clinical signs of polyneuropathy. In neuropsychological tests, slight visuoconstructive apraxia, and disturbances of verbal memory and cognitive function were observed. Magnetic resonance imaging (MRI) revealed cerebral lesions in two patients. After transplantation, muscle strength reverted to normal in all patients, polyneuropathy improved and in all but 2 patients recovery of neuropsychological functioning was observed. Clinical signs of encephalopathy had disappeared. All patients were emotionally better adjusted after transplantation. Four subjects showed new, albeit mild changes in neurophysiological and neuropsychological tests postoperatively. We conclude that the majority of neurological impairment disappeared after liver transplantation. We want to stress that evaluation of neurological sequelae of liver transplantation needs to be based on assessments both before and after liver transplantation.

Neurobehavioral outcome 1 year after severe head injury. Experience of the Traumatic Coma Data Bank

The outcome 1 year after they had sustained a severe head injury was investigated in patients who were admitted to the neurosurgery service at one of four centers participating in the Traumatic Coma Data Bank (TCDB). Of 300 eligible survivors, the quality of recovery 1 year after injury was assessed by at least the Glasgow Outcome Scale (GOS) in 263 patients (87%), whereas complete neuropsychological assessment was performed in 127 (42%) of the eligible survivors. The capacity of the patients to undergo neuropsychological testing 1 year after injury was a criterion of recovery as reflected by a significant relationship to neurological indices of acute injury and the GOS score at the time of hospital discharge. The neurobehavioral data at 1 year after injury were generally comparable across the four samples of patients and characterized by impairment of memory and slowed information processing. In contrast, language and visuospatial ability recovered to within the normal range. The lowest postresuscitation Glasgow Coma Scale (GCS) score and pupillary reactivity were predictive of the 1-year GOS score and neuropsychological performance. The lowest GCS score was especially predictive of neuropsychological performance 1 year postinjury in patients who had at least one nonreactive pupil following resuscitation. Notwithstanding limitations related to the scope of the TCDB and attrition in follow-up material, the results indicate a characteristic pattern of neurobehavioral recovery from severe head injury and encourage the use of neurobehavioral outcome measurements in clinical trials to evaluate interventions for head-injured patients.

Impairment and recovery profiles of sensory-motor function following stroke: single-case graphical analysis techniques

Graphical analysis procedures have been developed to improve interpretation of sensory-motor tests from individual subjects following acute brain damage. The procedures have been applied to 11 unilateral stroke patients assessed serially over 12 months on a computerized quantitative sensory-motor test battery of which grip strength, arm speed, and tracking have been chosen for illustrative purposes. The results indicate that four graphs are necessary to fully demonstrate neurologic impairment and recovery of each sensory-motor function, although fewer graphs would be satisfactory in some applications. Such analyses have proven valuable in the display of serial performance of individual patients but demonstration of impairment and recovery is much more difficult than for group analyses.

The relationship between neuropsychological function and brain damage detected by neuroimaging after closed head injury

Studies relating neuropsychology and structural neuroimaging after closed head injury are reviewed. Particular attention is given to the question of the relative contribution of focal and diffuse damage to neuropsychological impairment. The evidence currently available emphasizes the importance of diffuse damage in closed head injury. Diffuse damage is not equally distributed in the brain, and the review suggests three axes that are relevant for neuropsychological function: (1) damage may be unilateral or bilateral, (2) damage is characteristically greater in anterior regions than posterior regions, and (3) damage shows a centripetal gradient. A large gap remains between the emergent generalizations concerning head injury and reliable neuropsychological interpretation of scans from individual patients.

Recovery of memory after severe closed head injury: dissociations in recovery of memory parameters and predictors of outcome

This study examined selective reminding and recognition memory performance of 21 severe closed-head injured patients tested within 6 months of regaining consciousness and then again after at least 1 year. Performances on selective reminding parameters were highly correlated and patients performed significantly worse at both testings than did hospitalized controls matched for age, education, and sex. Patients improved from testing 1 to testing 2 on only four of six memory variables. Average Impairment Rating at testing 1 was a marginally better predictor of memory performance at testing 2 than was length of coma. Results are discussed in terms of (a) utility of selective reminding parameters and predictors of outcome and (b) dissociations in recovery of memory parameters.

Diencephalic amnesia: a reorientation towards tracts?

The principal thalamic and hypothalamic structures implicated in mnemonic information processing are the mediodorsal nucleus of the thalamus, the pulvinar, anterior thalamus, and laterodorsal nucleus, the mamillary body, and the mamillothalamic tract and internal medullary lamina. Determining the contribution of an individual region in memory is quite difficult as it is nearly impossible to find a circumscribed damage of only one region. On the contrary, some illnesses affecting primarily the diencephalon, such as Korsakoff's disease, tend to involve several structures together. Furthermore, even when cases with similar circumscribed diencephalic damage can be found, these will not necessarily demonstrate the same outcome on the behavioral level. Therefore, the role or contribution of individual memory-related diencephalic structures has to be inferred by comparing a number of cases and by then extracting distinct features common to a given group. Such an approach revealed that the contributions of the two fiber systems mentioned above, mamillothalamic tract and internal medullary lamina, might be more important in processing information long-term than had been acknowledged previously and might be more important than that of the nuclear masses mentioned, especially of the mediodorsal thalamus. This outcome underlines the view that emphasizing interactions between brain regions rather than single static masses will provide a more realistic picture of how the nervous system acts in information processing.