Neuropsychological impairment correlates with hypoperfusion and hypometabolism but not with severity of white matter lesions on MRI in patients with cerebral microangiopathy.
BACKGROUND AND PURPOSE: Cerebral microangiopathy, indicated on MRI by lacunar infarctions (LI) and deep white matter lesions (DWML), is said to lead to vascular dementia. METHODS: Fifty-seven patients with proven cerebral microangiopathy were assessed for changes in regional cerebral blood flow (rCBF) and glucose metabolism (rMRGlu) and compared with 19 age-matched controls. The findings were correlated with results of extensive neuropsychological testing, as well as with MRI findings. A special head holder ensured reproducibility of positioning during rCBF (single-photon emission CT [SPECT]), rMRGlu (positron emission tomography [PET]), and MR imaging. White matter and cortex were quantified with regions of interest defined on MRI and superimposed to corresponding PET/SPECT slices. LI and DWML were graded by number and extent. RESULTS: Even with severe DWML and multiple LI, rCBF and rMRGlu values were not reduced. ANOVAs identified brain atrophy and neuropsychological deficits as the main determinants for reduced rCBF and rMRGlu values in both cortex and white matter. Neuropsychological deficits correlated well with decreased rCBF and rMRGlu, whereas MRI patterns such as LI and DWML did not. Factor analysis revealed no correlation of LI and DWML with rCBF, rMRGlu, atrophy, and neuropsychological deficits, showing instead positive correlations between rCBF, rMRGlu, and neuropsychological performance and negative correlations of the latter 3 with brain atrophy. CONCLUSIONS: From these data, we conclude that LI and DWML are epiphenomena that may morphologically characterize cerebral microangiopathy but do not in themselves indicate cognitive impairment. Dementia or neuropsychological deficits, by contrast, are reflected exclusively by functional imaging parameters (rCBF, rMRGlu) and cerebral atrophy. (+info
Current trends in cognitive rehabilitation for memory disorders.
Progress in the neuropsychology of memory disorders has provided a foundation for development of cognitive rehabilitation for amnesic patients. Accumulating evidence in the past two decades suggested that certain training techniques could be beneficial to many amnesic patients, such as teaching and acquisition of domain-specific knowledge, motor coding, reality orientation, and meta-cognition improvement. In this article we review and discuss the current trends in cognitive rehabilitation of memory disorders and provide a future direction in this emerging field. In addition, our experience in the successful rehabilitation of Korsakoff syndrome patients is also introduced. (+info
Silent lacunar lesions detected by magnetic resonance imaging of children with brain tumors: a late sequela of therapy.
BACKGROUND: Cerebral lacunes, which generally appear on magnetic resonance imaging as foci of white matter loss, usually occur in adults after ischemic infarcts. We report the development of lacunes in children after therapy for brain tumors. PATIENTS AND METHODS: We reviewed the clinical characteristics and radiologic studies of 524 consecutive children with brain tumors treated over a 10-year period. We documented the neuropsychologic findings associated with lacunes and the factors predictive of lacunar development. RESULTS: Lacunes developed in none of the 103 patients observed or treated with surgery alone. Twenty-five of the 421 patients treated with chemotherapy or radiation therapy or both had lacunes. Patients were a median of 4.5 years old at the time of both diagnosis (range, 0.3 to 19.8 years) and radiotherapy (range, 1.5 to 20 years). Fourteen patients were treated with craniospinal irradiation, and 11 were treated with local radiotherapy. The median time from radiotherapy to the appearance of lacunes was 2.01 years (range, 0.26 to 5.7 years). For all patients, lacunes were an incidental finding with no corresponding clinical deficits. The factor most predictive of lacunar development was age less than 5 years at the time of radiotherapy (P =.010). There was no significant difference in estimated decline in intelligence quotient scores between patients with lacunes and age and diagnosis-matched controls. CONCLUSION: Lacunes may be caused by therapy-induced vasculopathy in children with brain tumors, with the most significant predictor being age less than 5 years at the time of radiotherapy. (+info
Neuropsychology: music of the hemispheres.
Music may be the food of love but it is also good fodder for cognitive scientists. Here we highlight a recent study of a neuropsychological patient who has lost her ability to read music, but not text, in the absence of any other musical deficit. (+info
Neuropsychology: time out of mind.
We have always known that some form of clock is needed to measure time. It now seems that a variety of different neural clocks are involved in determining our temporal perceptions, some specialised for shorter and some for longer durations. (+info
A review of neuropsychological services in the United Kingdom for patients being considered for epilepsy surgery.
We report a review of the current practice of neuropsychologists working within epilepsy surgery services. The aim of the review was to examine areas of diversity and consensus across current national service provision and to examine progress in service delivery since a previous survey in 1994. Sixteen centres provided information via a questionnaire on three areas of clinical practice: pre- and post-surgery neuropsychological protocols; the intracarotid sodium amytal protocol; patient and family expectations and psychological health, in addition to examining aspects of the context of clinical practice such as the role and experience of the psychologist and future service priorities. Findings of the review suggest that, whilst progress has been made towards fulfilling the recommended guidelines for services, there remain a number of areas for development in terms of the provision of a consistent nationwide service delivery approach. Cognitive assessment and the ICSA procedure remain essential components of the neuropsychology service. Assessment of psychological health and quality of life is now carried out by a growing number of centres, although these remain areas for further development. Consensus was found in terms of the need to establish centres of excellence, and to develop appropriate training for neuropsychologists in the field. (+info
Clinical review: Intensive care follow-up--what has it told us?
The majority of intensive care practitioners, until comparatively recently, was content to discharge surviving patients to the care of referring primary specialty colleagues who would undertake subsequent inpatient and outpatient care. With the exception of mortality statistics from clinical studies, the practitioners were thus denied the opportunity of understanding the full impact of critical illness on a patient and their family. The concept of the intensive care follow-up clinic has developed more recently, and is run commonly on multidisciplinary lines. These clinics serve a number of purposes, but importantly have drawn attention to broader patient-centred outcomes after intensive care. Investigators are just beginning to identify, and in some cases quantify, the postdischarge burden on patient and family; additional useful data have also come from follow-up of specific disease states. The purpose of the present review is to highlight some of the important issues that impact on recovery from critical illness towards an acceptable quality of postdischarge life. We have concentrated on the adult literature, and specifically on studies that inform us about the more general effects of critical illness. Head and spinal injury are thus largely ignored, as the effects of the primary injury overwhelm the effects of 'general' critical illness. (+info
The time course of selective visual attention: theory and experiments.
Historically, the psychophysical evidence for "selective attention" originated mainly from visual search experiments. A first important distinction in the processing of information in visual search tasks is its separation in two stages. The first, early "preattentive" stage operates in parallel across the entire visual field extracting single "primitive features" without integrating them. The second "attentive" stage corresponds to the specialized integration of information from a limited part of the field at any one time, i.e. serially. So far, models based on the above mentioned two-stage processes have been able to distinguish features from conjunction search conditions based on the observed slopes of the linear relation between reaction time (i.e., search time) and the number of items in the stimulus array. We propose a neuroscience based model for visual attention that works across the visual field in parallel, but due to its intrinsic dynamics can show the two experimentally observed modes of visual attention, namely: the serial focal attention and the parallel spread of attention over space. The model demonstrates that neither explicit serial focal search nor saliency maps need to be assumed. In the present model the focus of attention is not included in the system but only emerges after convergence of the dynamical behaviour of the neural networks. Furthermore, existing models have not been able to explain the variation of slopes observed in different kinds of conjunction search modes. We hypothesize that the different slopes can be explained by assuming that selective attention is guided by an independent mechanism which corresponds to the independent search for each feature. The model consistently integrates the different neuroscience levels by considering the microscopic neurodynamical mechanism that underlies visual attention, the different brain areas of the dorsal or "where" and ventral or "what" paths of the visual cortex, and behavioural data. (+info