Author and graduation date: Sabra Lynn BONELLI, May, 1999

Committee members: Larry S. Verity (Chair), Dennis J. Selder, Rebecca B. Bryon

Thesis title: The Relationship of Verbal Recall Memory and Physical Activity in Type 2 Diabetics and Nondiabetics

Diabetes mellitus is a chronic disease that reportedly affects 15.7 million people in the United States. Numerous studies have suggested persons engaging in regular physical activity possess increased cognitive abilities, including verbal memory processes. Additional recent studies have shown that type 2 diabetes adversely affects cognitive function, especially verbal memory functioning. To date however, few studies have attempted to assess the relationship between physical activity and cognition in type 2 diabetics. Thus, the purpose of this study was to examine the relationship between verbal memory cognition and physical activity in type 2 diabetics and nondiabetics. A total of 26 subjects volunteered to participate in this study and completed a health history questionnaire. The 13 type 2 diabetics were 61.2 + 13.6 years old with a BMI of 32.4 + 10.3 kg/nf and a WHR of .96 + 0.95. The 13 nondiabetics were 60.2 + 13.2 years old with a BMI of 32.0 10.4 kg/M7 and a WHR of .93 + .08. No significant differences were found between the diabetics and nondiabetics for Age Ct = -19, -D = .85), BMI Ct = -12, p = .91) or WHR Ct = -.97,.p = .34). To determine habitual physical activity level, two physical activity questionnaires, the Paffenbarger Physical Activity Questionnaire and the Minnesota Leisure Time Physical Activity Questionnaire, were completed and found to be highly correlated (r == 56,.p = .003). This study found correlations between BMI and Total score for the Minnesota LTPA Cr -.43, V = .029) and between WHR and Paffenbarger score (r = .42, p = .043). All subjects were administered the Buschke Selective Reminding Test to assess verbal recall memory'. Correlations were found between age and the total number of words recalled on the Buschke test (r = -.59,.p = .001), and between education level and Buschke trial where short-term recall reached zero (r = .49, p = .001). This study, however, found no significant differences on verbal memory scores for the diabetic and nondiabetic groups, and no effects of physical activity on verbal memory were revealed. Reasons for the lack of significant findings, are most likely attributable to the study limitations. For all t tests tile alpha level was set at 0.05 to minimize the possibility of type I errors; however, the sample size of each group 13) severely compromised the likelihood of finding significant results. Additionally the diabetics in this study showed well-controlled blood pressure and demonstrated physical activity levels similar to the nondiabetic population. The physical activity habits were uncharacteristic for diabetics; therefore, it is thought they are not representative of the general type 2 diabetic population. Further, diabetes-related disease complications and glycemic control were not directly measured in this study, both of which are known to be related to cognitive dysfunction. It is plausible that the type 2 diabetics in this study had well-controlled glucose levels and minimal disease-related complications which would explain the similarity to nondiabetics on verbal memory test results. Further, there was great variability of age in both the diabetic and nondiabetic groups, as well as a large variability in score results for the all physical activity and verbal memory variables. Future research should be done to address each of the above limitations in an attempt to more clearly establish the relationship between verbal memory and physical activity in type 2 diabetics versus nondiabetics.

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