| dc.description.abstract | Type 2 Diabetes (T2D) has been shown to affect brain structures responsible for attention and grip force control. Precision grip force relies on complex tuning of upper-extremity forces. The primary aim of this study was to assess dual-task costs (DTC) in older adults with T2D through tasks involving attention and precision grip force control. The level of attention given to a task may depend on how rested an individual is, and rest is mainly obtained through sleep. Studies have shown that people with T2D have decreased sleep quality, compared to controls, and that poor sleep leads to lower cognitive function. Thus, sleep quality should be taken into consideration when measuring DTC in older adults with T2D. Moreover, understanding the amount of information processing capacity used for task performance (i.e., cognitive workload) is also important. Therefore, this dissertation study measured cognitive DTC c(DTC), motor DTC (mDTC), cognitive workload, and sleep quality in older adults with T2D. DTCs were measured through the scores on the Digit Span Forward Test (DSFT) and Peak of the Grip Force Rate (PGFR), collected from 12 older adults with T2D and 21 control individuals. All participants also responded to the Pittsburgh Sleep Quality Index (PSQI), a questionnaire on sleep quality. A subset of participants had their pupillometric data collected and transformed into an Index of Cognitive Activity to measure cognitive workload. This dissertation is comprised of four chapters. Chapter 1 presents an introduction to this dissertation’s theme. T2D definition, epidemiology, and effects to nervous system and cognitive function are briefly described. Methods to assessing cognitive and motor function, such as precision grip force control, are presented. Previous studies on cognitive workload and sleep quality in older adults with T2D are also presented. Chapter 2 presents results on DTC and cognitive workload. Although both cDTC and mDTC were not statistically significant between groups, ICA revealed higher cognitive workload for T2D group during single cognitive task (i.e., DSFT). Higher cognitive workload may be a compensatory strategy to avoid decrements on cognitive performance and dual-task performance in older adults with T2D. Chapter 3 presents results on the relationship between sleep quality and DTCs. No significant correlations were found between PSQI scores and cDTC and mDTC in either groups of older adults with or without T2D. However, PSQI scores were used to categorize participants into “good sleepers” and “poor sleepers”, and poor sleepers presented lower cDTC and higher depression symptoms as compared to good sleepers. The data suggests that poor sleepers prioritized the cognitive task, whereas good sleepers prioritized the motor task. One of the limitations of this study was using PSQI as a sole measurement of sleep. Future studies should use objective sleep measures (e.g., actigraphy) in combination to subjective measures. In addition, our dual-task paradigm may not have been sufficiently challenging to elicit DTCs to be correlated to sleep quality. Future studies may test participants with more complex tasks. Chapter 4 presents a summary of this dissertation work. Although DTCs of older adults with T2D was not significantly different than control group, ICA was higher for T2D group during single cognitive task and dual-task. Sleep quality was not correlated to DTCs in either groups of older adults (T2D or control), but sleep quality scores proved successful in distinguishing cDTC and depression symptoms between older adults characterized as good sleepers or bad sleepers. One of the major limitations of this dissertation study is its small sample size, partially explained by lack of interest of potential participants due to no monetary compensation. Future studies should consider using neurophysiological measures to assess cognitive effort besides assessing task performance and using objective sleep measures (e.g., actigraphy) in combination to sleep questionnaires. | |
