Magnetic resonance imaging volumetric assessment of the extent of contrast enhancement and resection in oligodendroglial tumors.

OBJECT: Oligodendrogliomas that enhance on MR images are associated with poor prognosis. However, the importance of the volume of enhancing tumor tissue, and the extent of its resection, is uncertain. The authors examined the prognostic significance of preoperative and residual postoperative enhancing tissue volumes in a large single-center series of patients with oligodendroglioma. They also examined the relationship between enhancement and characteristic genetic signatures in oligodendroglial tumors, specifically deletion of 1p and 19q (del 1p/19q). METHODS: The authors retrospectively analyzed 100 consecutive cases of oligodendroglioma involving patients who had undergone T1-weighted gadolinium-enhanced MRI at diagnosis and immediately after initial surgical intervention. The presence of preoperative enhancement was determined by consensus. Preoperative and residual postoperative volumes were measured using a quantitative, semiautomated method by a single blinded observer. Intrarater reliability for preoperative volumes was confirmed by remeasurement in a subset of patients 3 months later. Intrarater and interrater reliability for residual postoperative volumes was confirmed by remeasurement of these volumes by both the original and a second blinded observer. Multivariate analysis was used to assess the influence of contrast enhancement at diagnosis and the volume of pre- and postoperative contrast-enhancing tumor tissue on time to relapse (TTR) and overall survival (OS), while controlling for confounding clinical, pathological, and genetic factors. RESULTS: Sixty-three of 100 patients had enhancing tumors at initial presentation. Presence of contrast enhancement at diagnosis was related to reduced TTR and OS on univariate analysis but was not significantly related on multivariate analysis. In enhancing tumors, however, greater initial volume of enhancing tissue correlated with shortened TTR (p = 0.00070). Reduced postoperative residual enhancing volume and a relatively greater resection of enhancing tissue correlated with longer OS (p = 0.0012 and 0.0041, respectively). Interestingly, patients in whom 100% of enhancing tumor was resected had significantly longer TTR (174 vs 64 weeks) and OS (392 vs 135 weeks) than those with any residual enhancing tumor postoperatively. This prognostic benefit was not consistently maintained with greater than 90% or even greater than 95% resection of enhancing tissue. There was no relationship between presence or volume of enhancement and del 1p/19q. CONCLUSIONS: In enhancing oligodendrogliomas, completely resecting enhancing tissue independently improves outcome, irrespective of histological grade or genetic status. This finding supports aggressive resection and may impact treatment planning for patients with these tumors.

[Attentional impairment after traumatic brain injury: assessment and rehabilitation]. / Alteraciones de la atención tras daño cerebral traumático: evaluación y rehabilitación.

INTRODUCTION: Attention disorders are a major problem after traumatic brain injury underlying deficits in other cognitive functions and in everyday activities, hindering the rehabilitation process and the possibility of return to work. Functional neuroimaging and neuropsychological assessment have depicted theoretical models considering attention as a complex and non-unitary process. DEVELOPMENT: Although there are conceptual difficulties, it seems possible to establish a theoretical background to better define attentional impairments and to guide the rehabilitation process. The aim of the present study is to review some of the most important pieces involved in the assessment and rehabilitation of attentional impairments. We also propose an appropriate model for the design of individualized rehabilitation programs. Lastly, different approaches for the rehabilitation are reviewed. CONCLUSIONS: Neuropsychological assessment should provide valuable strategies to better design the cognitive rehabilitation programs. It is necessary to establish a link between basic and applied neuropsychology, in order to optimize the treatments for traumatic brain injury patients. It is also emphasized that well-defined cognitive targets and skills are required, given that an unspecific stimulation of cognitive processes (pseudorehabilitation) has been shown to be unsuccessful.

Strategies in probabilistic categorization: results from a new way of analyzing performance.

The "Weather Prediction" task is a widely used task for investigating probabilistic category learning, in which various cues are probabilistically (but not perfectly) predictive of class membership. This means that a given combination of cues sometimes belongs to one class and sometimes to another. Prior studies showed that subjects can improve their performance with training, and that there is considerable individual variation in the strategies subjects use to approach this task. Here, we discuss a recently introduced analysis of probabilistic categorization, which attempts to identify the strategy followed by a participant. Monte Carlo simulations show that the analysis can, indeed, reliably identify such a strategy if it is used, and can identify switches from one strategy to another. Analysis of data from normal young adults shows that the fitted strategy can predict subsequent responses. Moreover, learning is shown to be highly nonlinear in probabilistic categorization. Analysis of performance of patients with dense memory impairments due to hippocampal damage shows that although these patients can change strategies, they are as likely to fall back to an inferior strategy as to move to more optimal ones.

Pre- and post-right middle cerebral artery stroke in a young adult: a case study examining the sensitivity of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

Right-hemisphere strokes are associated with a number of neurobehavioral deficits. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a relatively new, but widely used screening battery; however, there is little published research in patients who have sustained strokes. We present a rare case of stroke in a 22-year-old psychiatric patient, who received neuropsychological evaluations before and after sustaining a right middle cerebral artery (MCA) stroke. The RBANS demonstrated sensitivity to post-stroke changes despite pre-stroke cognitive impairments and a complex psychiatric overlay, with the Visuospatial/Constructional index being one of the most sensitive indicators of right hemisphere dysfunction. Line Orientation fell from normal to defective levels; these findings were associated with decline in related standard neuropsychological measures.

[Assessment of recognition of emotions by healthy persons and patients with focal brain pathology].

To assess the involvement of different structures of the human brain into successive stages of the recognition of the principal emotions by facial expression, we examined 48 patients with local brain lesions and 18 healthy adult subjects. It was shown that at the first (intuitive) stage of the recognition, premotor areas of the right hemisphere and temporal areas of the left hemisphere are of considerable importance in the recognition of both positive and negative emotions. In this process, the left temporal areas are substantially involved into the recognition of anger, and the right premotor areas predominantly participate in the recognition of fear. In patients with lesions of the right and left brain hemispheres, at the second (conscious) stage of recognition, the critical attitude to the assessment of emotions drops depending on the sign of the detected emotion. We have confirmed the hypothesis about a correlation between the personality features of the recognition of facial expressions and the dominant emotional state of a given subject.

Task alternation cost without task alternation: measuring intentionality.

A behavioral dissociation between intention and action was demonstrated by patient AF who sustained damage to the left-hemisphere including the basal ganglia. The patient was tested in a task switching paradigm involving two choice reaction-time tasks: SIZE (small/large) and SHAPE (circle/square). The last block in each of the two sessions involved only one task. AF switched tasks reasonably well in the first 40 trials, but unlike her matched control group, in all the remaining trials when two tasks were involved, she performed only the SIZE task. Interestingly, although no task switching took place, AF continued to demonstrate behaviorally her intention to switch tasks. First, she exhibited "task alternation cost", poorer performance relative to instructed single-task trials. Second, shifting to an instructed single-task condition was accompanied by an initial response slowing, indicating a change in goal-state. Finally, when instructed to switch tasks, AF demonstrated the "task-congruency effect", indicating interference from the instructed but competing stimulus-response mapping. Two groups of university students were instructed to perform only the SIZE task, after initial switching, either while ignoring the SHAPE cues ("Ignore") or while being prepared for the SHAPE task only when the cue appeared in red, which never happened ("Attend color"). AF's performance resembled the one of the "Attend color" group and not the "Ignore" group. The results indicate that AF had a partially activated intention to switch tasks. The implications to intentionality and task switching theory are discussed.

A new shoulder range of motion screening measurement: its reliability and application in the assessment of the prevalence of shoulder contractures in patients with impaired consciousness caused by severe brain damage.

OBJECTIVES: To determine the reliability of a new shoulder joint range of motion (ROM) measurement for unconscious patients and to assess the prevalence of shoulder joint contractures in such patients. DESIGN: Prospective cohort survey. SETTING: An early rehabilitation center for adult persons with neurologic disorders. PARTICIPANTS: Fifty patients with impaired consciousness caused by severe cerebral damage of various etiologies. In addition, reference values were measured in 60 healthy adults. INTERVENTION: Shoulder ROM was assessed by measuring the distance between the olecranon and underlay while the patient lay supine on a solid surface and the patient's hands were passively positioned behind the neck. Distances between the olecranon and underlay were measured, first, manually by the rater and, second, for control, digitally by a blinded person from a digital photo taken while a constant force was applied to the elbow. MAIN OUTCOME MEASURES: Prevalence of contractures defined as increased distance between the olecranon and underlay or impossibility of positioning the hands passively behind the neck, and intra- and interrater-reliability of the 2 shoulder ROM measurements with the interclass correlation coefficient (ICC). RESULTS: Measurement of shoulder ROM showed high intra-(ICC range, .78-.91) and interrater reliability (ICC range, .77-.90) for manual measurement, high intra- (ICC range, .91-.95) and interrater reliability (ICC range, .90-.94) for the digital analysis, and a high ICC for both methods (ICC=.87). The prevalence of shoulder contractures was 56% in the patients and 50% of all shoulder joints. CONCLUSIONS: The described method provided a reliable measurement for reduced shoulder ROM and appears to be a useful screening method to show the prevalence of shoulder joint contracture in these patients.

Multiparametric iterative self-organizing MR imaging data analysis technique for assessment of tissue viability in acute cerebral ischemia.

BACKGROUND AND PURPOSE: Defining viability and the potential for recovery of ischemic brain tissue can be very valuable for patient selection for acute stroke therapies. Multiparametric MR imaging analysis of ischemic lesions indicates that the ischemic lesion is inhomogeneous in degree of ischemic injury and recovery potential. We sought to define MR imaging characteristics of ischemic lesions that are compatible with viable tissue. METHODS: We included patients with supratentorial ischemic stroke who underwent multiparametric MR imaging studies (axial multi-spin-echo T2-weighted imaging, T1-weighted imaging, and diffusion-weighted imaging) at the acute (< 24 hours) and outcome (3 months) phases of stroke. Using the algorithm Iterative Self-Organizing Data Analysis Technique (ISODATA), the lesion was segmented into clusters and each was assigned a number, called the tissue signature (white matter = 1, CSF = 12, all others between these two). Recovery was defined as at least a 20% size reduction from the acute phase ISODATA lesion volume to the outcome phase T2-weighted imaging lesion volume. The tissue signature data were collapsed into the following categories: < or = 3, 4, 5, and > or = 6. Logistic regression analysis included the following parameters: lesion volume, tissue signature value, apparent diffusion coefficient (ADC) value, relative ADC (rADC) expressed as a ratio, T2 value, and T2 ratio. The model with the largest goodness of fit value was selected. RESULTS: We included 48 patients (female-male ratio, 26:22; age, 64 [+/-14] years; 15 treated with recombinant tissue plasminogen activator [rt-PA] within 3 hours of onset; median National Institutes of Health Stroke Scale score, 7 [range, 2-26]). Median symptom onset-to-MR imaging time interval was 9.5 hours. With ISODATA processing, we generated 200 region-of-interest tissue records (one to nine tissue records per patient). Regarding tissue recovery, we detected a three-way interaction among ADC, ISODATA tissue signature, and previous treatment with rt-PA (P = .003). In the group not treated with rt-PA, ischemic tissues with acute rADC greater than the median (0.79) and tissue signature < or = 4 were more likely to recover (80% vs. 31% and 13%, odds ratio [95% CI]: 0.12 [0.05, 0.30] and 0.04 [0.01, 0.18] for tissue signatures 5 and 6, respectively). CONCLUSION: ISODATA multiparametric MR imaging of acute stroke clearly shows inhomogeneity and different viability of the ischemic lesion. Ischemic tissues with lower acute phase ISODATA tissue signature values (< or = 4) and higher rADC values (> or = 0.79) are much more likely to recover than those with higher signature values or lower rADC values. The effect of these factors on tissue recovery, however, is dependent on whether preceding treatment with rt-PA had been performed. Our approach can be a valuable tool in the design of therapeutic stroke trials with an extended time window.

Fetal biophysical profile and cerebro-umbilical ratio in assessment of brain damage in growth restricted fetuses.

OBJECTIVE: To examine the relationship between fetal biophysical profile (FBP), Doppler cerebro-umbilical (C/U) ratio and neonatal neurosonography in growth restricted newborns. STUDY DESIGN: This prospective study included 87 growth restricted fetuses from 28 to 42 weeks of gestation. The FBP and C/U ratio were assessed twice a week. Within 48h and on the seventh day after birth, neonatal neurosonography was performed as the outcome parameter. RESULTS: Brain damage was detected, by neurosonography, in 34 newborns with intrauterine growth restriction (IUGR). Severe periventricular echodensities (PVE) were ultrasonographically verified in eleven infants. Intraventricular or intraparenchymal hemorrhage (severe intracranial hemorrhage ICH) was detected in seven infants, and subependymal hemorrhage (SEH) in nine infants with IUGR. Porencephalic cysts, as a result of chronic intrauterine hypoxia, were found in four infants, and brain atrophy was detected in one case. Nonspecific ultrasonographic changes were observed in two newborns. The FBP and C/U ratio were statistically significantly associated with neurosonographicaly verified neonatal brain lesions (P < 0.001). CONCLUSIONS: The FBP and the C/U ratio represent the useful indicators for early detection and assessment of fetal hypoxia. They may also be parameters for the prediction of neonatal neurosonography findings in newborns with IUGR.

Patients with right frontal lesions are unable to assess and use advice to make predictive judgments.

Frontal lobe damage impairs decision-making. Most studies have employed gambling and probabilistic tasks, which have an emotional (reward-punishment) component and found that patients with ventromedial sector lesions have exceptional difficulty performing normally on these tasks. We have recently presented an economic decision-making task to patients and normal volunteers that required them to not only forecast an economic outcome but also to weigh advice from four advisors about the possible outcome across 40 trials. We studied 20 patients with right frontal lobe lesions and 9 patients with parietal lobe lesions and compared their performance to 20 matched controls. Frontal lobe lesion patients were inconsistent at using advice and their forecasts were poor. Patients with dorsolateral but not orbito-frontal lesions showed some ability to assess advice. Patients with parietal lobe lesions were good at assessing advice but were slow at doing so; they were consistent but poor at using advice and their use of advice was unrelated to their forecasting. All three patient groups were overconfident in their own performance. In contrast, controls could both use and assess advice, their ability to use advice was mediated by their ability to assess it, and they were not overconfident. Group differences on an overall measure of accuracy on this task were associated with an ability to accurately plan. Differences in ability to assess and forecast were associated with planning and working memory performance. These findings indicate that patients with both right dorsolateral and orbito-frontal lesions may be impaired when required to make complex decisions related to forecasting and judgment. Our findings enlarge the scope of decision-making deficits seen in patients with frontal lobe lesions and indicate additional circumstances in which patients with frontal lobe lesions will have difficulty in deciding.

Neonatal EEG: a powerful tool in the assessment of brain damage in preterm infants.

Serial EEG recordings beginning immediately after birth are not only of great diagnostic and prognostic value but also useful to elucidate the timing and the mode of brain injuries in the preterm newborn. It is extremely useful to distinguish between acute stage and chronic stage EEG abnormalities. The former is characterized by findings of acute depression such as increased discontinuity, decreased faster frequency activities, and lowered amplitudes. The latter mainly includes dysmature patterns and disorganized patterns. The timing of brain insult can be assessed by considering EEG findings in relation to the time of birth. Different modes of brain injury are associated with different types of EEG abnormalities and different types of neurological outcome. Sudden strong brain insults are usually associated with findings of severe depression followed by disorganized pattern and later cerebral palsy, while persistent mild insults are usually associated with prolonged mild depression followed by dysmature pattern and later mental retardation. Routine serial EEG studies in preterm infants demonstrated that one fourth of cerebral palsies in these infants were of antenatal origin, two thirds of perinatal origin and postnatal injuries played the least role. Periventricular leucomalacia (PVL) manifesting itself on the ultrasound in the late neonatal period and suggesting postnatal origin was often found to be of antenatal origin with an EEG soon after birth. PVL without apparent causes was often associated with abnormal fetal heart rate patterns and early neonatal EEG abnormalities, and considered to have originated in the antepartum period.

Outcomes 5 years post-traumatic brain injury (with further reference to neurophysical impairment and disability).

The assessment of recovery and outcomes post-traumatic brain injury (TBI) has often been poorly researched and reported in past literature. Indeed, an accurate documentation of outcomes in this population had never been performed in the state of South Australia. To redress this situation this study collected data on people who had sustained a TBI 5 years previously, using medical records, personal interview/questionnaire and neurophysical assessment in order to investigate broad outcomes as well as the specific nature and prevalence of any residual physical impairment and disability. The results (n = 67) indicate that the subjects' living arrangements had not altered significantly, and nearly half had returned to some form of paid work, though over 50% were reliant on the welfare system. The majority (57%) felt they had improved in all areas, 19% partially improved and 8% felt they had actually deteriorated. Considering the physical data, the most frequent areas of residual impairment were headaches, followed by balance difficulties and fatigue/weakness. Functionally, 30% had some degree of deficit in upper limb activity and 9% required assistance for particular transfer tasks. Overall balance was impaired in 34% and gait was altered in 24% with 9% reliant on wheelchairs for mobility. Such data may be used in the education of people with TBI and those who live and/or work with them, as well as in future studies assessing the impact of various factors on recovery and outcomes. Evidence was also provided that residual physical issues should be considered along with the more researched areas of cognition and psychosocial issues.

Continuous assessment of the cerebral vasomotor reactivity in head injury.

OBJECTIVE: Cerebrovascular vasomotor reactivity reflects changes in smooth muscle tone in the arterial wall in response to changes in transmural pressure or the concentration of carbon dioxide in blood. We investigated whether slow waves in arterial blood pressure (ABP) and intracranial pressure (ICP) may be used to derive an index that reflects the reactivity of vessels to changes in ABP. METHODS: A method for the continuous monitoring of the association between slow spontaneous waves in ICP and arterial pressure was adopted in a group of 82 patients with head injuries. ABP, ICP, and transcranial doppler blood flow velocity in the middle cerebral artery was recorded daily (20- to 120-min time periods). A Pressure-Reactivity Index (PRx) was calculated as a moving correlation coefficient between 40 consecutive samples of values for ICP and ABP averaged for a period of 5 seconds. A moving correlation coefficient (Mean Index) between spontaneous fluctuations of mean flow velocity and cerebral perfusion pressure, which was previously reported to describe cerebral blood flow autoregulation, was also calculated. RESULTS: A positive PRx correlated with high ICP (r = 0.366; P < 0.001), low admission Glasgow Coma Scale score (r = 0.29; P < 0.01), and poor outcome at 6 months after injury (r = 0.48; P < 0.00001). During the first 2 days after injury, PRx was positive (P < 0.05), although only in patients with unfavorable outcomes. The correlation between PRx and Mean index (r = 0.63) was highly significant (P < 0.000001). CONCLUSION: Computer analysis of slow waves in ABP and ICP is able to provide a continuous index of cerebrovascular reactivity to changes in arterial pressure, which is of prognostic significance.

Assessment of the dysexecutive syndrome in schizophrenia.

BACKGROUND: Cognitive neuropsychological theories hypothesize a role for frontal lobe executive deficits in the aetiology of schizophrenic symptoms. The study examined the performance of a schizophrenic group on the Behavioural Assessment of the Dysexecutive Syndrome (BADS; Wilson et al. 1996), a test battery which assesses the 'everyday' difficulties associated with the dysexecutive syndrome. Performance of the schizophrenics was contrasted with that of brain injured and healthy volunteer groups. METHODS: Matched groups of 31 schizophrenic patients, 35 patients with brain injuries and 26 healthy volunteers were administered the BADS. Patients were also given tests of general intelligence and memory. Patients and their relatives/carers also completed a questionnaire rating day-to-day failures of executive functioning. RESULTS: Schizophrenic and brain-injured patients showed impairment on the BADS, compared to healthy controls. There were no significant differences between the two patient groups. Significant impairment was found in a subgroup of 16 schizophrenics who showed otherwise intact general intellectual functioning, suggesting the existence of a specific executive deficit. Among the schizophrenic patient group there was evidence of a dissociation between executive and memory impairments. A significant correlation existed between performance on the BADS and relatives ratings of executive problems for the brain injured group, but not for the schizophrenic group. CONCLUSIONS: The BADS is a useful tool for identifying executive deficits in people with a diagnosis of schizophrenia, especially those who are otherwise generally intellectually intact. This is particularly important in the context of rehabilitation and community transition programmes.

[Scoring and validation of the Clock Face Test in psychometric assessment of elderly subjects]. / Cotation et validation du test du cadran de l'horloge en psychométrie chez le sujet âgé.

AIMS: To propose an original evaluation and validation of the Clock Face Test (CFT). METHOD: Outpatients; 163 elderly people, aged over 65 years. Factory analysis, Student's test. RESULTS: The test shows a positive correlation with Folstein's MMSE (r = 0.769) and Signoret's BEC 96 (r = 0.644), a good specificity (75% with MMSE; 79% with BEC 96) and a good sensitivity (87% with MMSE; 74% with BEC 96). Four factors are identified by factory analysis; 74% of the variancy is explained by the first three factors. CONCLUSION: The CFT is a valid tool, easy to conduct. Several applications are possible for diagnosis, psychometric control and therapeutic trials.

[Assessment of spontaneous motor activity in young infants: an effective method for the detection of brain function disorders]. / De beoordeling van spontane motoriek van jonge baby's: een doeltreffende methode voor de opsporing van hersenfunctiestoornissen.

A method for the assessment of the brain function of young infants was recently introduced. It consists of evaluation of the quality of spontaneously generated generalized movements (general movements, GMs). GMs appear at an early stage of pregnancy and persist until approximately the 4th month after term. Normal GMs are characterized by the triad of complexity, variation and fluency. Mildly abnormal GMs. indicating mild dysfunction of the nervous system, are not fluent but jerky or stiff. Markedly abnormal GMs, indicating major nervous system dysfunction, are characterized mostly by absence of complexity and variation of the movements: the movements are monotonous and stereotyped. The quality of the GMs can be evaluated by means of so-called global Gestalt perception. The technique can be learned in a few days. The quality of the GMs has a clear predictive significance for the child's development. Children with normal GMs will be free of handicaps in later life, whereas three-quarters of the children showing clearly abnormal GMs throughout the postnatal GM period do develop handicaps. Assessment of the quality of the GMs is a relatively cheap, non-invasive method of evaluating the current and future brain function of young infants.