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Biomedical subjects

G E Chatrian

Publications and source records attributed to G E Chatrian.

33 records · Page 2Linked to original sources
PubMed1975

Cerebral responses to electrical tooth pulp stimulation in man. An objective correlate of acute experimental pain.

The pulp of individual teeth of 17 normal adult volunteers was electrically stimulated via pairs of electrodes implanted into dentine. Computer-summated responses recorded from the surface of the head were composed of two concurrent sequences of events, one of which was seen maximally over midline areas and the other over the lower portions of the postcentral regions. Appropriate tests demonstrated that these wave forms represented cerebral tooth pulp-evoked potentials. Because tooth pulp-evoked potentials represent objective, quantifiable, nonverbal concomitants of central events associated with the perception of noxious stimuli, they may prove helpful in investigating acute experimental pain in man.

Adult↗
PubMedDate not supplied

Cochlear summating potential to broadband clicks detected from the human external auditory meatus. A study of subjects with normal hearing for age.

The cochlear summating potential (SP) preceding the auditory nerve compound action potential (AP) was elicited by broadband alternating condensation and rarefaction clicks and recorded by noninvasive electrodes from the external auditory meatus (EAM) of 60 volunteers of both sexes, 12 to 67 years old, who had normal hearing for age. Quantitative data were obtained on: the number of ears displaying measurable SPs; the SP detection level; the SP onset, peak and rise times; the duration of the SP-AP complex; the SP amplitude; and the SP/AP amplitude ratio. Previously unknown relationships were unveiled between the amplitude, but not the temporal, measures of the SP and laterality, sex, age, and audiometrically determined hearing thresholds to 4 to 8 kHz tones. The highest correlations were obtained with these last thresholds, which suggested that receptors in the basal turn of the cochlea played a dominant role in the generation of the EAM-detected SP. To improve on existing techniques for determining abnormal SP elevation, a multiple regression method was devised that utilized sex, age, 4 to 8 kHz hearing thresholds, and AP voltage to establish upper normal limits of SP amplitude for individual subjects and ears.

Acoustic Stimulation↗
PubMedDate not supplied

Long-term EEG-video-audio monitoring: detection of partial epileptic seizures and psychogenic episodes by 24-hour EEG record review.

Twenty-seven patients with medically refractory paroxysmal disorders underwent EEG-video-audio (EVA) monitoring in an inpatient neurology-neurosurgery unit over 1-15 (mean 8.9) days. Fast visual review of all EEG records (5,784 h) and subsequent analysis of synchronized EVA patterns demonstrated a total of 208 partial epileptic seizures (ES) in 12 individuals and 87 psychogenic episodes (PE) in 15 subjects. Clinical ES lasted 83.3 s on the average and were most frequent from day 7 to 9 of monitoring (42.3%) and during sleep (56.4%). PE were longer in duration (mean 724.5 s), most numerous during the first 2 days of monitoring (41.4%), and occurred exclusively during wakefulness. Subjects with PE signaled (by pressing on a push button) more events (35.6%) than did the individuals with ES (27.9%). Multiple observers raised the proportion of alarms to 69.0% of PE compared to 39.9% of ES. Following the alarm, nurses reached the patients' bedside within a brief time (mean 22.2 s). To differentiate partial ES from PE or to establish the association of these disorders, EVA monitoring is best performed around the clock over a period of 1-2 weeks. The limited number of paroxysmal events, especially ES, signaled by the patients should be considered when designing studies of the effectiveness of pharmacologic, surgical, and other treatments.

Adolescent↗
PubMedDate not supplied

Epileptic nystagmus.

Two cases of epileptic nystagmus (EN) are described. The first patient had no history of seizures and experienced attacks of EN associated with oscillopsia and followed by horizontal diplopia and esotropia. These episodes could be triggered by certain visual stimuli and ocular pressure. The second patient had a history of generalized tonic-clonic seizures. He displayed episodes of EN that changed direction in the course of the attacks simultaneously with a shift of the EEG discharge from one occipital region to the other. Cortical blindness followed postictally. On recovery from the postictal state, both patients were neurologically normal. With standard electrodes, the EEG seizures associated with EN involved the occipital, posterotemporal, and parietal areas of the scalp contralateral to the fast phase of the nystagmus. In the first patient, use of supplementary scalp electrodes further localized the seizures to an anterior occipital site intermediate between standard occipital and posterotemporal electrodes. Thirty-six previously reported cases of EN were associated with partial seizures. Horizontal EN most commonly results from seizure activity involving the occipital cortex, although participation of adjoining portions of the parietal and temporal cortexes is possible.

Adult↗