Date of Completion


Thesis Type

College of Arts and Science Honors



First Advisor

Julie Dumas


cognition, insulin resistance, glucose


Growing evidence suggests that impaired glucose tolerance may contribute to the development of cognitive dysfunction in otherwise healthy individuals (Neergard et al., 2017). The goal of this study was to clarify the relationship between pre-clinical insulin resistance, as estimated by plasma glucose levels, and cognitive functioning in older adults. It was hypothesized that glucose levels at the higher end of the normal range are associated with cognitive dysfunction and with differences in brain activation during a working memory task. Participants completed the Brief Cognitive Rating Scale (BCRS; Reisberg et al., 1988), Global Deterioration Scale (GDS; Reisberg et al., 1982), Mattis Dementia Rating Scale (MDRS; Mattis, 1988), Repeatable Battery for the Assessment of Neuropsychological Status (RBANS; Randolph et al., 1988), Cognitive Change Index (CCI; Saykin et al., 2006), Symbol Digit Modalities Test (SDMT; Forn et al., 2013), and the Delis-Kaplan Executive Function System (D-KEFS; Delis et al., 2001). A series of correlations between fasting glucose levels and cognitive test performance was computed. Fasting glucose levels were positively associated with BCRS and GDS scores but no other measures. In addition, an independent samples t-test comparing cognitive performance of the high glucose group (glucose ≥ 100 mg/dL) and low glucose group (glucose < 100 mg/dL) indicated performance differences in executive functioning and verbal fluency. BMI was an additional factor associated with cognitive dysfunction. This study and future studies with larger sample sizes may help to inform new blood glucose control guidelines in healthcare, as even the higher end of the normal blood glucose range may be associated with cognitive decline.