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Biomedical subjects

D G Thomas

Publications and source records attributed to D G Thomas.

At least 289 records · Page 16Linked to original sources
PubMed1976

Cranioplasty.

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Acrylates↗
PubMed1976

Lactic dehydrogenase isoenzymes following head injury.

Serial levels of lactic dehydrogenase (LDH) isoenzymes have been measured in 92 neurosurgical patients with damaged brains, including 77 suffering from head injury. Serum LDH isoenzymes 1 and 2 rise in the injured group and generally reflect the degree of parenchymal brain damage. The method has possible diagnostic applications, as well as some prognostic use.

Brain Injuries↗
PubMed1975

Urodynamic observations following spinal trauma.

A method of the urodynamic investigation of paraplegic and quadriplegie patients is described. Serial measurements of the urethral pressure profile in patients with developing reflex micturition demonstrate a rising pressure at the external urethral sphincter with time following spinal trauma. Patterns of micturition with detrusor-sphincteric imbalance are described in patients with both early and well-established reflex micturition.

Adolescent↗
PubMed1968

Ruptured liver.

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Abdominal Injuries↗
PubMedDate not supplied

Analyses of single-trial N1 amplitude and latency variability and their influence on the average evoked potential.

Sixteen adult subjects listened to tone pips superimposed on Bach concertos and either attended to the tones or to the music. Auditory evoked potentials (EPs) were recorded to the tones in both conditions from C3 and C4 each referenced to linked ears. Although the expected Condition X Hemisphere interaction was not found, a main effect for Condition showed that N1 amplitude in the average EPs (AEPs) was greater in the Tones condition. P2 showed no significant main effects or interactions. The AEP was used as a template to identify N1 in each single-trial wave form. The difference in AEP amplitude between conditions was subsequently found to be due primarily to enhanced N1 amplitude in the single-trial wave forms, and not to a decrease in latency variability. This template-matching procedure appears to be a valid method for identifying N1 in single-trial wave forms based on the following findings: (1) multiple regression analyses demonstrated that 90-99% of the variance of the amplitude of N1 in the average EP could be accounted for by a weighted linear combination of single-trial amplitude and latency variability; (2) the values of the correlation coefficients between the AEP template and the single-trial EPs were generally very high, averaging approximately +0.91; (3) the distributions of the latency of N1 in the single-trial EPs were not flat as would be expected if random noise were being identified as N1.

Adult↗
PubMedDate not supplied

Event-related potential measures of attention in moderately depressed subjects.

Prior research has inferred attentional changes related to depression from evidence concerning other cognitive processes. The present experiment investigated attentional changes related to depression in a more direct manner. Subjects were 32 young adults attending college. Depression was measured by self-report measures. In an auditory selective attention task similar to that of Hansen and Hillyard (1980), auditory event-related potentials (ERPs) were recorded from central (Cz) and frontal (Fz) scalp locations. Evidence for selective attention was manifest as the difference wave (Nd), which showed larger mean and peak amplitudes for the less difficult of two attention conditions. Nd was also shown to have an earlier peak latency at the Cz scalp location. However, there was no significant difference between the Depressed and Control groups as measured by the Nd wave. Significant differences were found between groups for the amplitude of the N1 peak of the ERP at the Fz scalp location. This suggests that the Depressed group differed in arousal level or sensory sensitivity from the Control group.

Acoustic Stimulation↗