Cognitive outcome and early indices of severity of head injury

Factors influencing recovery from mild traumatic brain injury

PRIMARY OBJECTIVE

This study determined whether initial GCS score, head CT results, cognitive performance on IMPACT testing, or APOE genotype most effectively predicted 1-month functional outcome after mild traumatic brain injury (mTBI). This study tested the hypotheses that participants with poor performance on initial cognitive testing and those with an APOEe4 genotype would exhibit a poorer 1-month recovery after mTBI.

RESEARCH DESIGN

Regression analysis determined which independent variables were most effective in predicting 1-month GOS-E or DRS score. Independent t-test procedures determined whether cognitive recovery varied across APOEe4 carriers.

METHODS AND PROCEDURES

49 participants admitted to the hospital with mTBI received cognitive evaluation within 48 hours after injury and again one month later. DNA analysis provided participant APOE genotype.

MAIN OUTCOMES AND RESULTS

Results showed that no study variables significantly predicted GOS-E or DRS scores, however, differences were identified when APOE groups were compared. Participants who were noncarriers of APOEe4 had significantly slower reaction times compared to APOEe4 carriers. Participants who were homozygous APOEe4 carriers had significantly lower instances of impulsivity than noncarriers.

CONCLUSIONS

Further research is needed to understand how APOE allele status and performance on initial cognitive testing may influence short-term recovery after mTBI.

"Galveston Orientation and Amnesia Test": tradução e validação

OBJETIVO: Traduzir e validar o Galveston Orientation and Amnesia Test para uso em nosso meio. MÉTODOS: Esse teste foi traduzido para o português e retro-traduzido para o inglês por diferentes especialistas na língua e por fim, feita a avaliação da equivalência entre o instrumento original e a versão retro-traduzida. Sua aplicação em 73 vítimas de trauma crânio-encefálico contuso e a indicação da gravidade dessa lesão, estabelecida pela Escala de Coma de Glasgow, permitiram verificar as propriedades de medida do instrumento. RESULTADOS: A confiabilidade verificada pelo Alfa de Cronbach resultou em 0,76. Houve indicação de validade convergente e discriminante do instrumento quando os resultados de aplicação do Galveston Orientation and Amnésia Test foram analisados perante a gravidade do trauma crânio-encefálico. CONCLUSÃO: Os resultados observados dão suporte para a aplicação do Galveston Orientation and Amnesia Test em nosso meio como indicador do término da amnésia pós-traumática.

A community survey demonstrated cohort differences in the lifetime prevalence of self-reported head injury

OBJECTIVE

The objective of the study was to assess the lifetime prevalence and validity of self-reported head injury.

STUDY DESIGN AND SETTING

Analysis of a cross-sectional community survey, stratified by birth cohort. Seven thousand four hundred eighty-eight residents of Canberra and Queanbeyan, 3,678 males and 3,810 females, representing three cohorts aged in their 20s, 40s and 60s at the time of the survey, were randomly selected from the Australian Electoral Roll.

RESULTS

The lifetime prevalence of head injury with at least 15 min loss of consciousness ranged from 5.6 to 6.0% across the three cohorts. Self-reported head injury was associated with symptoms of traumatic brain injury or postconcussion syndrome. Reported head injury did not differ across the birth cohorts, contrary to expectations that prevalence rates would increase with age. Analysis of age at first head injury showed significant differences between cohorts in the reported prevalence at age 20, with estimates considerably higher for the youngest cohort.

CONCLUSION

Although the data may reflect real increases in the risk of head injury, it may be that self-reported measures of lifetime prevalence of head injury underestimate prevalence in older cohorts.

Neuropsychological outcome in relation to the traumatic coma data bank classification of computed tomography imaging

The Traumatic Coma Data Bank (TCDB) classification of CT (computed tomography) scan has been related to the general outcome and intracranial pressure evolution. Our aim was to analyse the relationship of this classification with neuropsychological outcome and late indices of ventricular dilatation. Fifty-seven patients with a moderate or severe head injury (mean admission Glasgow Coma Scale Score, 7.7) were studied from 122 consecutive cases. There were 49 males and 8 females (mean age, 27.7 years). Subjects were classified into TCDB categories on the basis of their most serious acute CT scan finding. From the last control CT scan image, performed at a mean of 6.12 months postinjury, several measures of ventricular dilatation were calculated. Neuropsychological assessment at 6-month included tests of verbal and visual memory, visuoconstructive functions, fine motor speed, and frontal lobe functions. Patients with diffuse injury type I showed better neuropsychological outcome than patients with more severe diffuse injuries and those with mass lesions. Within the diffuse injury groups, the degree of diffuse damage was related to measures of verbal memory and attention and cognitive flexibility. Ventricular enlargement was more evident in patients with mass lesions and it decreased in the remaining groups as the severity of diffuse injury diminished. These results show that there is a relationship between acute intracranial lesion diagnosis according to TCDB classification and neuropsychological results and ventricular dilatation indices at 6 months postinjury.

Factors associated with balance deficits on admission to rehabilitation after traumatic brain injury: a multicenter analysis

OBJECTIVE

To evaluate how demographics, measures of injury severity, and acute care complications relate to sitting and standing balance in patients with traumatic brain injury (TBI).

DESIGN

Multicenter analysis of consecutive admissions to designated TBI Model Systems of Care (TBIMS).

SETTING

Ten National Institute for Disability and Rehabilitation Research TBI Model System centers for coordinated acute and rehabilitation care.

PARTICIPANTS

908 adults with TBI were included in the study.

MAIN OUTCOME MEASURES

Sitting and standing balance were assessed within 72 hours of admission to inpatient rehabilitation.

RESULTS

Age less than 50 years had a significant association with normal sitting and standing balance (P =.001 and.05, respectively). Measures of severity of traumatic brain injury, including admission Glasgow Coma Score, length of posttraumatic amnesia (PTA), length of coma, and acute care length of stay were each significantly related to impaired sitting and standing balance ratings (P <.01). Initial abnormalities in pupillary response had a significant relationship with impairment of sitting (P =.009) but not standing balance. Incidence of respiratory failure, pneumonia, soft tissue infections, and urinary tract infections were all related to impaired sitting balance (P <.01). Presence of intracranial hemorrhages did not have a significant relationship with either sitting or standing balance. Intracranial compression had a significant relationship with standing (P =.05) but not sitting balance. A discriminant function analysis, which included neuroradiological findings, injury severity, and medical complications, could not accurately predict impaired balance ratings.

CONCLUSIONS

This study demonstrated that rehabilitation admission balance ratings have a significant relationship with age, multiple measures of severity, and acute care medical complications after TBI. Prospective studies are indicated to evaluate the role balance at rehabilitation admission plays in the functional prognosis of patients with TBI.

Post-traumatic amnesia after closed head injury: a review of the literature and some suggestions for further research

Post-traumatic amnesia (PTA) is a transient sequela of closed head injury (CHI). The term PTA has been in clinical use for over half a century, and generally refers to the subacute phase of recovery immediately after unconsciousness following CHI. The duration of PTA predicts functional outcome after CHI, but its pathophysiological mechanism is not known. This paper compares current methods of determining the duration of PTA, summarizes reports on neuropsychological deficits in PTA, reviews available data that allow inferences about its mechanism, and suggests methods for further exploration of its pathophysiology.

Sitting balance following brain injury: does it predict outcome?

Balance dysfunction is commonly observed following traumatic brain injury. There are many proposed predictors of functional outcome in the traumatic brain injury population. It was hypothesized that the degree of balance dysfunction on admission to rehabilitation would be a significant predictor of the need for assistance at discharge, as measured by the Functional Independence Measure (FIM). This study involved 237 cases of traumatic brain injury patients admitted to a rehabilitation unit between November 1989 and September 1996. Using a multiple regression model, controlling for age, initial Glasgow Coma Score (GCS), rehabilitation admission strength, sitting balance and standing balance, it was found that the degree of impairment in sitting balance at admission to rehabilitation was a significant predictor of Discharge FIM-Total (FIM-T) score (p < 0.0001) and also of selected elements from the Discharge FIM-Motor (FIM-M) score (p < 0.0005). The combination of age, initial admission GCS, rehabilitation admission strength, standing balance and sitting balance accounted for 29% of the variance in the Discharge Total FIM score. Among these, sitting balance was the second most powerful predictor of both selected elements of the Discharge FIM motor score and discharge FIM-T. Sitting balance predictive capacity was exceeded in power only by age. Impairments in sitting balance appear to have a significant impact on functional outcome. Emphasis on unique rehabilitation techniques to treat balance dysfunction in the adult TBI population is warranted.

Prognosis in presumptive hypoxic-ischemic coma in nonneurologic trauma

BACKGROUND

The neurologic outcome of comatose patients has a wide variation from complete reawakening to death. Methods of predicting the outcome of coma caused by either head injury or cardiac arrest have been the subject of much discussion in the literature. However, prediction of neurologic prognosis in comatose trauma patients without head injury has rarely been discussed. We reviewed our experience in treating patients with presumptive hypoxic-ischemic coma after trauma and tried to identify factors relating to their neurologic outcomes.

METHODS

Thirty-six patients with normal brain computed tomographic scans, who remained comatose 10 minutes after stabilization of their hemodynamic status, were studied. Serial motor response, verbal response, pupillary light reflex, presence of spontaneous breathing and seizure, and blood glucose level were recorded to evaluate their roles in predicting neurologic outcomes.

RESULTS

There were five deaths (mortality rate, 14%) and 11 patients (31%) with neurologic deficits. An absence of spontaneous breathing, a blood glucose level greater than 300 mg/dL during resuscitation, and a presence of seizure signified a poor prognosis. Initial neurologic evaluation at 10 minutes after stabilization of hemodynamic status was not accurate in predicting outcome. A motor response worse than withdrawal from painful stimuli at 24 hours after injury and an absence of pupillary light reflex at 48 hours after injury predicted a poor neurologic outcome, with a 100% accuracy rate.

CONCLUSION

Hypoxic-ischemic coma in patients sustaining major trauma yielded a significantly better survival and neurologic outcome than that induced by cardiac arrest or head injury. Decision-making in the first 24 hours after injury should not be affected by the patient's neurologic status at that time. A motor response worse than withdrawal at 24 hours after injury and an absence of pupillary light reflex at 48 hours after injury predicted a poor neurologic outcome.

The acute period of recovery from traumatic brain injury: posttraumatic amnesia or posttraumatic confusional state?

OBJECT

The goal of this study was to characterize more fully the cognitive changes that occur during the period of acute recovery after traumatic brain injury (TBI).

METHODS

The pattern of performance recovery on attention and memory tests was compared with the results of the Galveston Orientation and Amnesia Test (GOAT). Tests of memory and attention were administered serially to a hospitalized group of patients with TBI of varying severity. The tests differed in their level of complexity and/or requirement for more effortful or strategic processing. The authors found a regular pattern to recovery. As expected, ability to perform on simpler tests was recovered before performance on more effortful ones. The ability to recall three words freely after a 24-hour delay (the operational definition in this study of return to continuous memory) was recovered last, later than normal performance on the GOAT. Ability to perform simple attentional tasks was recovered before the less demanding memory task (recognition); ability to perform more complex attentional tasks was recovered before the free recall of three words after a 24-hour delay. This recovery of attention before memory was most notable and distinct in the group with mild TBI.

CONCLUSIONS

The period of recovery after TBI, which is currently termed posttraumatic amnesia, appears to be primarily a confusional state and should be labeled as such. The authors propose a new definition for this acute recovery period and argue that the term posttraumatic confusional state should be used, because it more appropriately and completely characterizes the early period of recovery after TBI.

Predicting survival from head trauma 24 hours after injury: a practical method with therapeutic implications

OBJECTIVE

To develop a method to predict long-term outcome after head injury and determine if outcome can be accurately predicted 24 hours after injury.

DESIGN

A retrospective review was performed on a study cohort of 672 head-injured patients admitted in coma (Glascow Coma Scale score < or = 8) who remained comatose for at least 6 hours, survived more than 24 hours, and had 6-month outcome data available. Stepwise logistic regression analysis was used to determine which clinical variables predicted 6-month outcome. Statistically significant clinical predictors were combined into a single examination variable (MPX score), which reflected a rank-ordering of examinations from worst to best, which was then further weighted by patient age. The relation between 6-month outcome and MPX score at admission and 24 hours was plotted and analyzed.

MEASUREMENT AND MAIN RESULTS

Age, best motor score, and pupillary reactivity at admission and 24 hours were significant predictors of outcome; extraocular motility was predictive at 24 hours only. Age was the most important independent predictor, followed by best motor score, pupillary reactivity, and extraocular motility. Combining these predictors into MPX score resulted in a set of graphs that reliably predicted long-term outcome. The 24-hour MPX data were better predictors of 6-month outcome and were more specific in predicting negative outcomes than admission data.

CONCLUSIONS

The method is simple to use, relying on bedside neurologic examination and a single graph, but appears to predict long-term outcome accurately as early as 24 hours after head injury. If validated on other large series of patients, this method could provide an objective and practical basis for terminating care in patients unlikely to survive a head injury.

Post-traumatic apallic syndrome following head injury. Part 1: clinical characteristics

Epidemiological studies made within the western countries indicate an incidence of 200-300 traumatic head injuries per 100 000 residents each year. Severe head injuries account for 5-25% of all head injuries; 10-14% of all severe head-injured patients develop into a vegetative state, in which a sleep-wake rhythm is apparent, but however in which there is no evidence of awakeness or reactivity to the environment. The most commonly used labels, in the German and international literature, for these patients are 'vegetative state', 'apallic syndrome' and 'coma vigile'. This clinical characterization is not sufficient. It is necessary to employ additional criteria to distinguish subsets of vegetative patients e.g. computerized tomography, magnetic resonance imaging, single photon emission tomography, electroencephalography, brainstem reflexes, evoked potentials, assessment scales, age, premorbid brain disorders. Diagnostic and prognostic parameters must form the basis for various decisions relating to patients' care and intervention.

Prediction of recovery from traumatic brain injury

This paper encompasses the prediction of early and late recovery from traumatic brain injury (TBI). Predictors of the duration of coma and the utilization of posttraumatic amnesia duration to predict residual memory function are discussed. The issues surrounding prediction of long-term neurobehavioral recovery from TBI are considered, particularly the patient and clinical variables that are related to intellectual recovery. Findings from the NIH Traumatic Coma Data are reviewed pertaining to testability as a criterion for outcome. In addition to discussing the relationship of specific neurologic indices of TBI as predictors, the results obtained using a regression model are summarized. Finally, the relationship of neuroimaging findings to neurobehavioral outcome is discussed including directions for future research.

Classification and regression trees (CART) for prediction of function at 1 year following head trauma

A cohort of 514 hospitalized head-injury survivors was identified based on their injury and 448 (87%) of them were followed for 1 year. Comprehensive neurobehavioral testing was performed 1 month and 1 year after injury. The authors developed predictions of six neuropsychological and two psychosocial outcomes 1 year after head injury. Prediction trees are presented for verbal IQ, Halstead's Impairment Index, and work status at 1 year. Early predictors of neurobehavioral outcome in survivors are similar to previously reported predictors of mortality. Extent (both depth and length) of coma and age are the medical and demographic variables most predictive of late outcome. Adding 1-month scores substantially improves prediction of neuropsychological variables. The classification and regression tree is a useful technique for predicting long-term outcome in patients with head injury. The trees are simple enough to be used in a clinical setting and, especially with 1-month scores, predictions are accurate enough for clinical utility.

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.

Prediction of psychosocial recovery after head injury with cognitive tests and neurobehavioral ratings

A series of 53 patients was studied using a battery of tests and a neurobehavioral rating scale on average 4 months after closed-head injury (CHI). Social outcome was assessed 1 year after injury by interviewing a family member. The results supported the hypothesis that tests of flexibility and programming rather than tests of cognitive skills predict psychosocial recovery after CHI. Spatial Learning with Self-Set Goals and Sorting were measures of flexibility and programming. Contrary to expectation, word fluency performance was unrelated to these measures, but was associated with conventional intelligence tests, which did not predict psychosocial recovery. Cognition/Energy deficit on the Neurobehavioral Rating Scale and increased age were useful predictors of poor psychosocial outcome, whereas computed tomography findings or the Glasgow Coma Score were weakly related to the outcome indices. Evidently, cognitive flexibility and mental programming are very important psychological prerequisites of social recovery after CHI.

Post-traumatic amnesia: still a valuable yardstick

Records of coma and post-traumatic amnesia (PTA) were collected for a group of 38 patients with closed head injury. The results confirmed earlier studies indicating that patients may have short or negligible coma but report prolonged PTA. Comparison of eight patients with prolonged PTA (> 7 days) and short coma (< 6 hours) with the rest of the group on MRI in the acute stage showed that these patients had significantly more extensive hemispheric damage. In the group as a whole both coma and PTA were related to the number of areas in central brain structures in which lesions were detected, but only PTA was significantly related to the number of hemispheric areas in which lesions were found. It is concluded that although both coma and PTA are related to brain damage they reflect disparate patterns of lesions. Assessment of PTA can thus provide additional information concerning severity of injury.

Predictors of outcome following severe head trauma: follow-up data from the Traumatic Coma Data Bank

Outcome as a function of employment status or return to school was evaluated in severely head-injured patients. A priori we selected the most salient demographic, physiological, neuropsychological and psychosocial outcome predictors with the aim of identifying which of there variables captured at baseline or 6 months would best predict employability at 6 or 12 months. Based on the patients evaluated at 6 months, 18% of former workers had returned to gainful employment and 62% of former students had returned to school. For those not back to work or school at 6 months, 31% of the former workers and 66% of the former students had returned by 12 months. Age, length of coma, speed for both attending and motor movements, spatial integration, and intact vocabulary were all significantly related to returning to work or school. The three most potent predictors for returning to work or school were intactness of the patient's verbal intellectual power, speed of information processing and age.

Severe head injury: should expected outcome influence resuscitation and first-day decisions?

An early 'prognosis' based on initial findings can influence clinical decisions. To evaluate the quality of first-day outcome prediction based on either clinical or neuroradiological information, we prospectively examined 100 consecutive severely head-injured patients from the surgical intensive care unit. The prognoses were always made by the same experienced neurosurgeon and neuroradiologist according to a contracted Glasgow Outcome Scale (GOS). Every patient's outcome was predicted according to a three-class GOS within 24 h after injury. Correct 'first-day' prognoses were made in 59 and 56% of the cases by the neuroradiologist and neurosurgeon, respectively. In those instances where the prognoses made by the clinician and the radiologist coincided, the prognoses were correct for 73% of the patients. Based on accepted criteria, the neuroradiologist tended to overpredict favorable outcomes and missed many of the unfavorable outcomes (dead or vegetative) whereas the clinician overestimated unfavorable outcomes. Our study showed that outcome prognosis of patients with severe head injury has limited accuracy when made within 24 h after the injury, although an improvement in accuracy occurred when there was agreement between clinical and radiological predictions. Even with sophisticated clinical and radiological technologies, it is not possible to predict outcome on the first day after the accident with sufficient accuracy to guide early management.

The Three Rivers Regatta accident: an EMS perspective

The Three Rivers Regatta accident occurred on August 7, 1988 when a Formula I racing craft collided with shore, injuring 24 spectators. The authors retrospectively examined the prehospital-based response for this multiple-casualty incident that used emergency medical service (EMS) physicians and 32 paramedics stationed at water and land-based posts to triage and evacuate 24 patients in 32 minutes. Patients were transported to 5 hospitals including 4 Level I trauma centers; this was accomplished in 53 minutes. The EMS response was unique in a number of respects. This was a prehospital-based rescue with the entire triage and stabilization phase accomplished by River Rescue units that transported paramedic divers, EMS physicians, and trauma supplies for 30 patients. Also of significance was the inordinate proportion of pediatric patients that accounted for 50% (12/24) of the cases. Successful medical care was the result of planning based on "Daily Routine Doctrine" or escalation of existing treatment protocol; adequate supplies, personnel and transport adapted to local geography and patient population; communications, including all services--EMS, police, and fire; and prehospital physician input to ensure correct triage order and patient disposition.

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.

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.

Neuropsychological recovery in patients with moderate to severe head injury: 2 year follow-up

Neuropsychological outcome and recovery of a group of 31 consecutive adult patients with moderate to severe head injuries were prospectively investigated over a 2-year period. A friend control group was used for comparison purposes. Based on the results we conclude: (1) there is marked impairment of a broad spectrum of neuropsychological functions at 1, 12, and 24 months postinjury; (2) coma length is significantly related to neuropsychological status at all three time periods, although the relationship is weaker at 12 and 24 months; (3) marked improvement in all functions occurs in the first year, while recovery in the second year appears more specific and may depend on the severity of the injury and type of function; (4) practice effects and variability over repeated measures cause difficulties in determining recovery and need to be addressed with larger samples.

Interpeduncular high-density spot in severe shearing injury

Thirty cases of severe shearing injury were analyzed utilizing serial computed tomography scans and clinical observations. Fatalities occurred in the majority of patients whose Glasgow Coma Scale scores at admission were 6 or less. The presence of perimesencephalic subarachnoid hemorrhage, hemorrhage in the corpus callosum, acute brain swelling, and intraventricular hemorrhage on computed tomography scans resulted in high mortality rates. In 13 patients, interpeduncular high-density spots were observed on computed tomography scans, which were performed in the acute stage of injury. Eight of these patients died, and those surviving had poorer neurological outcomes than corresponding patients with identical Glasgow Coma Scale scores on admission. In the management of severe shearing injury patients, more attention should be given to the presence of interpeduncular high-density spots as well as other important diagnostic computed tomography findings regarding diffuse brain injury.

Head injury, a multivariate study: predicting long-term productivity and independent living outcome

As the second of a two-part research project, this study attempted to build three clinically useful prediction equations; these equations would be used to predict three long-term functional outcomes: productivity status, living arrangement status, number of hours of assistance required per week. There were ten predictor variables used in each analysis. These ten variables belonged to four theoretical classes: pre-injury demographics, pre-injury social characteristics, severity of injury, and post-injury environmental variables. The analytical method used was the General Linear Model of multiple regression, rather than the most often used Stepwise regression procedure. The results indicate that in none of the three prediction equations was more than 28% of the criterion variance accounted for, and only a minority of the predictor variables were significant predictors. It is concluded that, while the equations are of only very limited utility, the theoretical model and the analytical technique will be useful for future investigators.

Relationships among pre- and post-injury intelligence, length of coma and age in individuals with severe closed-head injuries

Relationships among pre-injury ability, post-injury verbal intelligence, duration of coma and age were analysed in 34 closed-head injury patients, 7-28 years of age, whose coma lengths ranged from 5 to 180 days. The results obtained suggest that moderate to severe closed-head injury uniformly impairs verbal intellectual functioning without regard to premorbid status. Premorbid ability test scores had a markedly low correlation (0.04) with Wechsler Verbal IQs, obtained after patients had plateaued in intellectual recovery. Even when the effects of coma and age were controlled, the correlation was not significant. Mean post-injury IQs for patients grouped according to pre-injury intelligence (above average, average, below average) were all in the 80s. The findings do not support the prevailing assumption that the greater the premorbid ability, the greater the potential for intellectual recovery and the better the outcome. This study instead suggests that the higher the pre-injury IQ, the greater the IQ point loss. This has important implications for rehabilitation, counselling, discharge planning and follow-up. The greater the disparity between pre- and post-injury IQs, the more profound the loss and, hence, the greater the need for patient and family adjustments, coping and modifications of future personal, educational and vocational plans.

Memory disorder related to coma duration after head injury

The relationship of memory and intelligence test performances to coma duration was studied in 51 head injured patients who had not been operated on for intracranial haematoma. Memory defect was related to coma duration, and was not secondary to impaired perceptual or conceptual analysis of the material to be remembered.

Disproportionately severe memory deficit in relation to normal intellectual functioning after closed head injury

The presence of disproportionate memory impairment with relatively preserved intellectual functioning was examined in 87 survivors of moderate or severe closed head injury. Approximately one-fourth of the patients tested at 5 to 15 and/or 16 to 42 months after injury manifested defective memory on both auditory and pictorial measures despite obtaining Wechsler Verbal and Performance Intelligence Quotients within the average range. The findings indicate that disproportionately severe memory deficit persists in a subgroup of closed head injured survivors which is reminiscent in some cases of the amnesic disturbance arising from other causes. Evaluation of long term memory in relation to cognitive ability could potentially identify important distinctions for prognosis and rehabilitation in head injured patients.

The correlation of EEG compressed spectral array to Glasgow Coma Scale in traumatic coma patients

We have studied 20 comatose intensive care patients with head injuries and/or intracranial haemorrhage in order to compare two different monitoring methods of the central nervous system. The level of unconsciousness was followed on the Glasgow Coma Scale (GCS). EEG was monitored continuously with the compressed spectral array (CSA)-method. CSA findings were classified into six categories according to the frequency content, reactivity and the amount of isoelectricity. The patients were divided into four groups according to the outcome: well-recovered, moderately recovered, poorly recovered and dead. The prognostic value of the data obtained with the GCS method was compared with that obtained by CSA. The CSA and GCS methods give information based on different neurophysiological backgrounds. This explains why the correlation of these methods was only moderate. When combining the information received from these two methods the predictability improved. In many acute situations CSA gave information about changes in the brain function, which could not be seen in GCS. The results suggest that CSA is not only a supplementary method to GCS but also a different approach to the monitoring of an unconscious patient.

Outcome prediction in comatose patients: significance of reflex eye movement analysis

An analysis of oculocephalic response and vestibuloocular reflex (VOR) in 81 patients with coma from various causes showed the importance of reflex eye movements for outcome prediction. Compared with oculocephalic response testing, VOR analysis provided more evidence and allowed more precise study of ocular motility in comatose patients. In 25 patients (31%) without conclusive or with absent oculocephalic response, a preserved VOR could be seen. The results indicated that in all cases with preserved VOR response (independent of the cause of coma) the assumption of a good outcome is justified and was correct in a maximum of 67%. The unpredictability in the other cases was largely due to non-neurological factors. Ninety two per cent of the patients with abolished reflex eye movements died. The combination of absent VOR and abolished pupillary light reaction allows prediction of negative outcome in 100% and shows the paramount importance of these two brainstem reflexes.