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Biomedical subjects

D E Sheer

Publications and source records attributed to D E Sheer.

14 recordsLinked to original sources
PubMed1992

Electrophysiological evidence of lateralized disturbances in children with learning disabilities.

This study used an electrophysiological measurement operation to investigate lateralized processing deficits associated with academic learning-disability subtypes. Fast frequency EEG activity in the 36-44 hertz (Hz) band was recorded from reading-disabled (RLD), arithmetic-disabled (ALD), and nondisabled control children engaged in verbal and nonverbal cognitive tasks. The control group, but neither LD group, exhibited a task-dependent shift in lateralization of 40 Hz EEG; the RLD subjects generated proportionately less left-hemisphere 40 Hz activity than control or ALD subjects during the verbal task; and the ALD subjects generated proportionately less right-hemisphere activity than control or RLD subjects during the nonverbal task. These results indicate that lateralized processing deficits are associated with different types of disabilities, and provide external validation of learning-disability classifications based on academic performance patterns.

Adolescent↗
PubMed1989

Focused arousal and the cognitive 40-Hz event-related potentials: differential diagnosis of Alzheimer's disease.

Focused arousal is a first-order energetic functional component of information processing, operative between sensory inputs and motor outputs. At the neural level of analysis, it represents a first-order interactive system of neural connectivity, providing a mechanism for the organization of unit specificities--coherent resonance at an optional periodicity in finite cell assemblies. Cognitive 40-Hz event-related potentials (CERP), loosely coupled with antecedent and concurrent stimuli, index the operation of focused arousal in circuitry convergent at parietal-temporal-occipital cortex. Methods are described for recording and computer-analyzing CERP, integrated with an automated behavioral testing procedure. The present report summarizes the results from a series of three studies where CERP was used to differentiate early Alzheimer patients from normal geriatrics, multi-infarct, and retarded depression patients. The three normal geriatric groups showed consistent task-dependent hemispheric lateralization. CERP was significantly higher in the left hemisphere with a verbal task, and in the right hemisphere, with a visual-spatial task. The Alzheimer patients showed no hemispheric lateralization and were markedly lower on CERP under all behavioral conditions, as compared with the normal geriatric, multi-infarct, and depression groups. Predictive efficiency of individual cases, differentiating Alzheimer patients from normal geriatrics, multi-infarct, and retarded depression patients, was 80 to 90 percent.

Aged↗
PubMed1980

Survey of training programs in clinical neuropsychology.

Reported the results of a survey of the membership of the International Neuropsychology Society with regard to patterns of training in clinical neuropsychology. Considerable variations in pre- and postdoctoral training and internship programs were found.

Education, Medical, Graduate↗
PubMed1978

Biofeedback training of 40-Hz EEG in humans.

This study was a preliminary evaluation of biofeedback training of human subjects to control high-frequency EEG responses in the 35- to 45-Hz (40-Hz) and 21- to 31-Hz ranges. A total of 22 adult males divided into three groups were successfully trained for increases or suppression of 40-Hz EEG, or increases of 21- to 31-Hz EEG. Dissociation of rates of 40-Hz EEG recorded from scalp leads and 40-Hz EMG responses from prominent muscle contaminators, and partial dissociation of 40-Hz and 21- to 31-Hz EEG responses were noted. After biofeedback training, 8 subjects demonstrated increase and suppression of 40-Hz EEG without feedback. No consistent descriptors of subjective experiences accompanying EEG changes were reported by subjects in any of the groups. The study suggests the utility of biofeedback procedures in research on high-frequency EEG activity.

Adolescent↗
PubMed1978

Behavioral and electroencephalographic correlates of 40-Hz EEG biofeedback training in humans.

Two groups of eight adults successfully trained with biofeedback for increases in 40-Hz EEG responses in left or right hemispheres also demonstrated significant 40-Hz EEG increases during baseline periods, and increases in the contralateral hemisphere during training periods. No changes in heart rate, 40-Hz EMG, or 21- or 31-Hz beta, alpha, or theta EEG occurred over training days. Three subjects returning for additional training demonstrated suppression of 40-Hz EEG. A group of four subjects experiencing daily bidirectional training produced substantial within-session control of 40-Hz EEG but no changes over days. Data from posttraining tests without feedback for successful subjects in both groups indicated significant control of 40-Hz EEG responses in the initial parts of these sessions, and some correlated changes in other EEG responses. Measures of successful subjects' experiences during training and control tests indicated awareness of changes in subjective concomitants of EEG responses. This study suggests further strategies for research on behavioral correlates of EEG activity.

Adolescent↗