Date of Award

1990

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Advisor

William Drew Gouvier

Abstract

This study was undertaken to examine the relationship between neuroanatomy of memory, the structural mechanics of closed head injury and the resulting effects on memory functioning. The experimental groups were composed of 30 closed head injured individuals equally divided by severity of injury based on posttraumatic amnesia (PTA). The first group included 15 mild head injured patients whose PTA was defined as less than 60 minutes. Group two was composed of 15 severely head injured patients whose PTA was greater than 24 hours. The comparison group consisted of 15 non-head injured volunteers matched to the experimental group by age, gender, race and education. The groups were essentially homogeneous with regard to age, education, premorbid intellectual functioning and time interval from injury to assessment. Within a single session, each subject was administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Wechsler Memory Scale-Revised (WMS-R) and the California Verbal Learning Test (CVLT). Univariate analysis of variance (ANOVA) tests followed by Tukey's Standardized Range Tests were used to analyze the data on 19 dependent variables. Significant differences in intellectual functioning were found between the severely head injured subjects and controls on Full Scale, Verbal and Performance IQ's. With regard to performance on the WMS-R, both the mild and severe individuals scored significantly lower than controls on verbal memory, visuospatial memory and delayed recall. Significant group differences were also indicated on 10 out of 11 CVLT variables which measured immediate and delayed free and cued recall and learning strategies employed by the subjects. The results of the study indicated that closed head injury produces severe deficits in learning and recall of both verbal and nonverbal stimuli, with degree of impairment related to severity of injury (PTA). Mild head injured persons exhibited deficits in consolidation of stimuli, whereas patients with severe head injury showed significant impairment in encoding, consolidation and retrieval reflecting cortical and subcortical damage.

Pages

88

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