A Voxel-Based Morphometry Study of Verbal and Visual Memory in Schizophrenia

Date of Submission

2013

Degree Type

Dissertation

Degree Name

Doctor of Psychology (PsyD)

Department

Psychology

Department Chair

Robert A DiTomasso, PhD, ABPP, Chair, Department of Psychology

First Advisor

Don Masey, PsyD, Chairperson

Second Advisor

Petra Kottsieper, PhD

Third Advisor

David Schretlen, PhD

Abstract

The aim of this study was to determine the relationship between brain structure and memory test performance in adult outpatients with schizophrenia (SZ). Sixty-four persons with SZ (mean age= 40.8, SD = 10.3 years) and 61 healthy controls (mean age=43.5, SD=11.2 years) completed the Hopkins Verbal Learning Test, BriefVisuospatial Memory Test, and brain magnetic resonance imaging. Voxel-based morphometry was used to quantify group differences in regional gray matter volume (GMV) and correlate regional GMV with memory test performance in persons with SZ. The SZ group performed worse than healthy controls on learning and delayed recall measures of both tests. Group differences were larger for verbal than visual learning and memory. Compared to healthy controls, patients with SZ showed reduced GMV in frontal, temporal and limbic lobes bilaterally, as well as the thalamus. Pearson correlations of GMV with cognitive performance revealed an unexpected pattern of hemispheric lateralization for verbal and visual memory, that learning and delayed recall did not correlate distinctly with frontal and temporal lobe volumes, and that most brain regions in which GMV correlated with cognitive performance differed from those that distinguished the two groups. Persons with SZ differ from healthy adults in both memory test performance and regional GMV. However, the minimal overlap between regions of reduced GMV that distinguish between groups and those that correlate with memory performance suggests that coarse neuroanatomic abnormalities in persons with SZ do not fully explain their impairment of learning and memory. These results highlight inconsistencies in our understanding of specific brain regions that subserve memory, and also indicate that memory likely depends on a myriad of structures.

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