Date of Award

1993

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Psychology

Keywords

Psychology, Clinical.

Supervisor

Shore, Douglas,

Rights

info:eu-repo/semantics/openAccess

Abstract

The purpose of the present investigation was to examine the efficacy of a RT procedure developed by David Shakow and colleagues for examining attentional deficit after BD. This procedure involves the presentation of a warning stimulus (a bell) followed by the presentation of an imperative stimulus (a light) 1, 2, 4, 7.5, or 15 seconds later. The time between the warning stimulus and the imperative stimulus (the Preparatory Interval (PI)) is either constant (in the Regular Procedure) or variable (in the Irregular Procedure). Two studies were conducted examining the performance of brain damaged subjects on Shakow's procedure. The subjects in Study one consisted of 154 BD patients, 30 normal control subjects, and 26 non-CNS damage hospitalized patient control subjects. The BD subjects were subdivided into four severity groups (Possible BD, and Mild, Moderate, and Severe BD) depending on their Average Impairment Rating (AIR) Scores. The subjects in Study two consisted of 18 BD patients who had been administered Shakow's procedure two times within the first 25 months after injury. Four questions were examined in Study One: whether the performance of the BD and control patients differed at the longest PIs, whether the performance differed at shorter PIs, whether summary RT measures could discriminate groups, and whether there were group differences in the profile shapes of the two procedures. Findings indicated that there were few differences in patterns of performances at the longer PIs and that no group showed a statistically significant crossover effect. There was a tendency for larger Redundancy Associated Deficits (RADs) to be seen with increasing severity of BD but there were no statistically significant differences in RADs between groups. In contrast, there were significant differences between groups at shorter PIs, with the differences being attributable primarily to BD subjects being much slower at the 1 second Irregular PI and BD patients being more affected by the length of the previous preparatory interval. Summary measures were generally found to be useful for discriminating the Severely and Moderately impaired BD subjects from the other groups but were less useful for discriminating more mildly impaired subjects from each other and from controls. Finally, profile analyses indicated that the curves of the six groups were not parallel for either procedure. However, the profiles were more different in shape for the Irregular Procedure than for the Regular Procedure. Study Two examined whether or not differences in profile shape and elevation would be seen across two testings of the same subjects. Findings indicated that the shapes of the profiles remained the same at both testings but that the profiles were less elevated at Testing Two. However, the difference in elevation was only statistically significant for the Irregular Procedure. The results were discussed in light of possible limitations of the study. The major conclusion was that an exclusive focus on group differences at longer PIs (i.e., the crossover effect) may be inappropriate because the strongest differences seen in the present study occurred at the shorter PIs. The importance of group differences at shorter PIs were discussed and suggestions for further research were made.Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .D653. Source: Dissertation Abstracts International, Volume: 54-09, Section: B, page: 4914. Adviser: Douglas Shore. Thesis (Ph.D.)--University of Windsor (Canada), 1993.

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