Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
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Studies on lateralization of cerebral metabolism during Wisconsin Card Sorting Test (WCST), a well-known paradigm of category learning, have shown mixed results. Moreover, sorting dimension (number, color and shape) is a cofounder of laterality in WCST. Functional transcranial Doppler sonography (fTCD) has a high temporal resolution and allows the measurement of mean cerebral blood flow velocity (CBFV) in the middle (MCA) and anterior cerebral arteries (ACA), which supply lateral and medial parts of the frontal and parietal lobes, respectively. We used fTCD to investigate CBFV changes occurring in both MCA and ACA during WCST and different sorting dimensions. ⋯ Functional transcranial Doppler sonography can be used to assess CBFV during WCST and different sorting dimensions, and the latter modulate reaction time and cerebral hemodynamics.
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Acute anemia slows the responses to clinical tests of cognitive function. We tested the hypothesis that these slowed responses during acute severe isovolemic anemia in healthy unmedicated humans result from impaired central processing. ⋯ The P300 latency appears to be a potential measure of inadequate central oxygenation. In healthy young adults with acute anemia, erythrocytes should be transfused to produce Hb>5-6 g/dL. As a temporizing measure, administration of oxygen can reverse the cognitive deficits and impaired central processing associated with acute anemia.
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To test a technique called Directed Transfer Function (DTF) for the estimation of human cortical connectivity, by means of simulation study and human study, using high resolution EEG recordings related to finger movements. ⋯ The estimation of cortical connectivity can be performed not only with hemodynamic measurements, by using functional MRI recordings, but also with modern EEG recordings treated with advanced computational techniques.
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Comparative Study
Long-term prospective on-line real-time seizure prediction.
Epilepsy, one of the most common neurological disorders, constitutes a unique opportunity to study the dynamics of spatiotemporal state transitions in real, complex, nonlinear dynamical systems. In this study, we evaluate the performance of a prospective on-line real-time seizure prediction algorithm in two patients from a common database. ⋯ These results suggest that the proposed seizure prediction algorithm could be used in novel diagnostic and therapeutic applications in epileptic patients.
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Comparative Study
The P50 midlatency auditory evoked potential in patients with chronic low back pain (CLBP).
Patients with Chronic Low Back Pain (CLBP) show arousal, attentional and cognitive disturbances. The sleep state-dependent P50 midlatency auditory evoked potential was used to determine if patients with CLBP [with and without co-morbid depression (DEP)] show quantitative disturbances in the manifestation of the P50 potential. ⋯ Patients with CLBP+DEP-med may be less able to disregard incoming sensory information, including painful sensations, but anti-depressant medications help correct this deficit. However, their perception of pain may be increased by medication.