Residual motor control and cortical representations of function following hemispherectomy: effects of etiology

Fifteen posthemispherectomy children were examined to assess residual motor function of the paretic side using the 74-point Fugl-Meyer Assessment of Motor Recovery scale. The degree of residual motor control differed for upper and lower extremities, with hand function being most severely impaired. Posthemispherectomy motor outcomes also differed as a function of etiology: cortical dysplasia, perinatal infarct, and Rasmussen's encephalitis. Children whose intractable seizures resulted from perinatal middle cerebral artery stroke demonstrated the most spared motor function. To detect cortical areas that represented motor control of the hemiparetic side, we focused on voluntary control of the affected lower extremity. Seven of our patients were able to carry out a foot dorsiflexion paradigm during functional magnetic resonance imaging, and these results were compared with activations found in normal controls. All children showed activations in the sensorimotor network ipsilateral to the affected side. The perinatal infarct group demonstrated greater activity in the cingulate cortex, whereas the Rasmussen's encephalitis group had significant activations in the insula, suggesting etiology-specific differences in reorganization. These findings are discussed in the framework of our understanding of mechanisms of cortical plasticity in the injured brain and its relevance to neurologic rehabilitation. We suggest that imaging techniques are important tools in identifying cortical regions underlying functional reorganization. Furthermore, detection of such areas might become a basis for specific training promoting the optimal reorganization of cortical networks to enhance motor control.     

Nontraumatic coma. Glasgow coma score and coma etiology as predictors of 2-week outcome

In 1987 and 1988, we carried out a prospective study of patients older than 10 years with nontraumatic coma in the intensive care units of Columbia-Presbyterian Medical Center, New York, NY. Of 188 patients with Glasgow Coma Scale (GCS) determinations within 72 hours, 61% were dead or in persistent coma by 2 weeks from onset. Age, sex, and ethnicity did not influence outcome. The 2-week outcome for patients with initial GCS of 3 to 5 was 14.8% awake; 85.2% were dead or in persistent coma. For the GCS 6 to 8 group, 53.1% were awake and 46.9% were dead or in persistent coma. Hypoxic or ischemic coma had the worst 2-week outcome (79% dead or comatose); coma caused by metabolic disease or sepsis (68%), focal cerebral lesions (66%), and general cerebral diseases (55%) were intermediate, while drug-induced coma had a favorable outcome (27% dead or comatose). The independent predictors of 2-week outcome were the first GCS and drug-induced coma. The predicted probability of waking at 2 weeks was eight times better for drug-induced coma than other causes when GCS was held constant. Patients with an initial GCS score of 6 to 8 were seven times more likely to waken than those with a score of 3 to 5. The motor subscore alone was a significant independent predictor of 2-week outcome. Modification of coma score to include etiology may give more accurate predictions of 2-week outcome after nontraumatic coma.     

Unilateral auditory language comprehension on the token test following cerebral commissurotomy and hemispherectomy

Two versions of the Token Test for auditory language comprehension were administered unilaterally to selected commissurotomy and post-infantile hemispherectomy patients. No deficit was found for the left hemisphere while the right showed a severe deficit comparable to that of left brain-damaged asphasics. Error analysis, however, revealed that the right hemisphere was more sensitive to perceptual and (short term auditory verbal) memory constraints in the task, whereas aphasics were more sensitive to linguistic variables. Mean overall scores of the right hemispheres on the Token Test were comparable to 4 yr old children as contrasted with a high mental age estimate—mean 11 yr— on the Peabody Picture Vocabulary Test. It is suggested that in the normally developing brain, distinct language functions exhibit disparate ontogeneses of lateralization in the left hemisphere.     

Self-report measures as predictors of psychotherapy outcome

A retrospective clinical study using existing patient records investigated the predictive value of a number of variables. Eighty-three new admissions to a large outpatient clinic completed a battery of eight self-report questionnaires that have been shown to be reliable and have a measure of discriminant validity. The battery consisted of items tapping anxiety, depression, obsessive-compulsive symptoms, phobias, borderline personality disorder, and histrionic, obsessive-compulsive, and paranoid personality styles. Outcome of therapy, which was predominantly dynamically-oriented, was assessed by residual difference scores computed from pre- and posttherapy Global Assessment Scale (GAS) ratings. Only patients attending five or more sessions (N = 37) were considered in the analyses. Patients high on the Anxiety Scale pretherapy showed relatively greater improvement in functioning than those with low initial scores. Patients scoring high on the Histrionic, Paranoid, and Obsessive-Compulsive Personality Scales showed the least relative improvement.     

Psychodynamic variables as predictors of psychotherapy outcome

Predicting the outcome of psychotherapy is a central concern in psychiatry. Twenty-one medical students seeking psychotherapy were evaluated on a number of psychodynamic and process variables using self-report scales and scales completed by the therapist before, during, and after psychotherapy. There were significant differences between patients and a comparison group on eight variables before therapy. Ten psychodynamic variables (six representing ego defense mechanisms) and four process variables were found to be highly correlated with outcome measures; the process variables were the best predictors of outcome. The data support the use of psychodynamic and process variables as predictors of outcome in psychoanalytically oriented psychotherapy.     

Imaging predictors of outcome following intravenous thrombolysis in acute stroke

Intravenous tissue plasminogen activator is the only approved medical treatment for patients with acute ischemic stroke. While it is associated with excellent clinical outcome in about 30 %, even with timely thrombolysis administration, certain strokes continue to evolve and lead to poor outcomes. Several studies have attempted to identify predictors of outcome despite timely thrombolysis. Persistence of a proximal clot burden and large vessel occlusion following thrombolysis are markers for patients who may potentially benefit from advanced treatment modalities like intra-arterial thrombolysis and thrombectomy. Timely brain imaging and interpretation play a crucial role in providing these treatment decisions. In this review, various imaging predictors of poor outcome among patients with acute ischemic stroke treated with intravenous thrombolysis are outlined. Despite identification of these imaging predictors, thrombolysis should not be withheld, as it may still be beneficial in a subset of patients. Knowledge of these predictors may set benchmarks for selecting candidates who may potentially benefit from advanced management strategies in future trials.     

The cognitive outcome of hemispherectomy in 71 children

PURPOSE: Long-term neuropsychological outcome was studied in 71 patients who underwent hemispherectomy for severe and intractable seizures at The Johns Hopkins Hospital between 1968 and 1997 and who agreed to participate. Seizures were due to cortical dysplasias (n = 27), Rasmussen syndrome (n = 37), or vascular malformations or strokes (n = 7). Both presurgical and follow-up results are available and reported for 53 patients. METHODS: Patients and caretakers were interviewed, and patients were administered standard measures of intelligence, receptive and expressive language, visual-motor skills, adaptive/developmental functioning, and behavior. RESULTS: Mean age at surgery was 7.2 years. At follow-up, on average 5.4 years after surgery, 65% are seizure free, 49% are medication free, and, of those responding, none rated quality of life as worse than before surgery. Mean IQ was in the 70s for Rasmussen and vascular patients and in the 30s for cortical dysplasia patients. Language and visual-motor skills were consistent with IQ. For Rasmussen patients only, language was significantly more impaired for left than for right hemispherectomy, both before surgery and at follow-up. Adaptive skills were mildly impaired, with greatest impairment in the physical domain. Cognitive measures typically changed little between surgery and follow-up, with IQ change <15 points for 34 of 53 patients; of the remainder, 11 declined and eight improved. Behavior was free of major problems, but social interactions and activities were limited. CONCLUSIONS: The most significant predictor of cognitive skills at follow-up was etiology, with dysplasia patients scoring lowest in intelligence and language but not in visual-motor skills. Regardless of etiology, most patients showed only moderate change in cognitive performance at follow-up.     

Educational skills: Long-term outcome and predictors following paediatric traumatic brain injury

Given that reading, spelling and arithmetic skills are acquired through childhood, their development may be compromised following a childhood traumatic brain injury (TBI). The present study examined educational skills (reading accuracy, spelling and arithmetic) at a mean follow-up interval of 6.8 years post-injury in children who had sustained a mild, moderate, or severe TBI at two ages: ‘Young’ (age at injury: 3–7 years, n = 48) and ‘Old’: (age at injury: 8–12 years, n = 36). Comparisons between the young and old TBI groups resulted in inconsistent findings. While a dose-response relationship for severity was evident for the young group, this was not always the case for the old group. Significant predictors of outcome included both severity and acute intellectual function.     

Arm and leg paresis as outcome predictors in stroke rehabilitation

I used leg and arm paresis to predict outcome measured as extremity function in a prospective study of 75 consecutive hemiplegic patients admitted to an inpatient stroke rehabilitation unit. In each patient, extremity paresis was quantified according to the five-point scoring system advised by the Medical Research Council, upper extremity function was quantified using the Barthel Index subscore for feeding and dressing the upper body, and lower extremity function was quantified according to a five-point scoring of the ability to walk. Improvement was recorded for upper extremity function in 52% of the patients and for lower extremity function in 89%. Best extremity function was reached a mean +/- SEM of 9 +/- 3 and 10 +/- 4 weeks after stroke for the upper and lower extremities, respectively. In patients experiencing complete recovery, this occurred a mean +/- SEM of 7 +/- 2 weeks (for both upper and lower extremities) after the stroke. Only 8-11% of the patients with paresis scores of less than or equal to 2 regained independent extremity function after rehabilitation. Half of the patients with paresis scores of greater than or equal to 3 regained independent extremity function after rehabilitation, while the other half were able to perform extremity function with only minimal assistance. As predictors of extremity function, the Barthel Index subscore was slightly better (r = 0.64) than paresis score (r = 0.58). However, because evaluation of extremity paresis is easy, it appears to be useful as a preliminary predictor of outcome following stroke.     

Demographic and cognitive predictors of long-term psychosocial outcome following traumatic brain injury.

Demographic factors and cognitive impairment have been found previously to have associations with outcome after brain injury. Kendall and Terry (1996) suggest that preinjury psychosocial functioning, neurological factors, and cognitive impairment have a direct relationship with multidimensional psychosocial adjustment, but that cognitive impairment also has an indirect relationship by means of the mediation of appraisal and coping variables. The aim of this study was to explore these theoretical relationships at very late stages of recovery after brain injury. A total of 131 participants who were more than 10 years after injury (mean = 15.31 yr) completed a neuropsychological assessment, plus outcome measures that included employment status, community integration, life satisfaction, quality of life (QoL), and emotion. Results indicated that injury severity was predictive of life satisfaction; gender and relationship status predicted community integration; and age at injury predicted employment status. Impairment in working memory directly predicted all outcomes except QoL and anxiety. An indirect relationship was also evident between working memory, life satisfaction, and depression. Results partially support Kendall and Terry's model but the variables that significantly influence outcome seem to be determined by the outcome dimensions selected.     

EEG prior to hemispherectomy: correlation with outcome and pathology

Hemispherectomy, for the treatment of seizures, is highly successful but has a significant morbidity rate. The procedure is usually restricted to patients with an intractable seizure disorder and hemiparesis. Because of the inherent risk of surgery, patient selection is a critical issue. This report describes the evaluation of background activity and ictal patterns on surface and invasive EEG in 12 children who underwent both anatomical (7) and functional (5) hemispherectomy in order to determine the role of electroencephalography in the selection of patients for hemispherectomy, and to correlate EEG findings with underlying pathology and outcome. A favorable outcome was predicted by an interictal EEG with two or more of the following: suppression over the abnormal hemisphere, absence of contralateral slowing, absence of generalized discharges and absence of bilateral independent spiking; or by unilateral onset of ictal discharges on invasive intracerebral EEG recording. Outcome did not correlate with the underlying pathology. Hemispherectomy can be successful in patients with a variety of predominantly unilateral pathologic entities.     

Development of above normal language and intelligence 21 years after left hemispherectomy.

Neuropsychologic follow-up studies of a 5 1/2-year-old boy who had left hemispherectomy for seizures showed that he had developed superior language and intellectual abilities. These findings contrast with recent reports indicating that the plasticity of the nervous system may have been overrated and contradict reports of restricted development of language functions after left and of nonlanguage functions after right hemispherectomy for perinatal lateralized brain lesions. Following removal of the left hemisphere, including "the classical language zones," the right hemisphere and other intact residual structures may provide the necessary substrata for the development of above normal adult language and intellectual capacities.     

Absence of S-cone input in human blindsight following hemispherectomy

Destruction of the occipital cortex presumably leads to permanent blindness in the contralateral visual field. Residual abilities to respond to visual stimuli in the blind field without consciously experiencing them have, however, been described in cortically blind patients and are termed 'blindsight'. Although the neuronal basis of blindsight remains unknown, possible neuronal correlates have been proposed based on the nature of the residual vision observed. The most prominent but still controversial hypothesis postulates the involvement of the superior colliculi in blindsight. Here we demonstrate, using a computer-based reaction time test in a group of hemispherectomized subjects, that human 'attention-blindsight' can be measured for achromatic stimuli but disappears for stimuli that solely activate S-cones. Given that primate data have shown that the superior colliculi lacks input from S-cones, our results lend strong support to the hypothesis that 'attention-blindsight' is mediated through a collicular pathway. The contribution of a direct geniculo-extrastriate-koniocellular projection was ruled out by testing hemispherectomized subjects in whom a whole hemisphere has been removed or disconnected for the treatment of epilepsy. A direct retino-pulvinar-cortical connection is also unlikely as the pulvinar nucleus is known to receive input from S-cones as well as from L/M-cone-driven colour-opponent ganglion cells.