Document Type

Dissertation

Date of Degree

Fall 2015

Degree Name

PhD (Doctor of Philosophy)

Degree In

Neuroscience

First Advisor

Steven W. Anderson

Abstract

Previous studies have shown that the experience of negative emotions is rarer, while experience of positive emotions is more frequent in the elderly, suggesting an overall improvement in emotional well-being as people age. However, most research did not account for the dynamic characteristics of emotions (e.g. peak intensity, latency, duration) and the levels of emotional challenges. In addition, since most previous studies have focused on studying the experience, expression, and psychophysiological response of emotion, it is still not fully understood how performance in cognitive or behavioral tasks (e.g., automobile driving) can be affected by emotions in older age. To address this gap, the current study examined the effect of normal aging on the dynamic processes of emotion during different levels of emotional challenge (aim 1), and the effect of emotion on driving in older adults as compared to middle-aged adults (aim 2). Parkinson’s disease (PD) is an age-related neurodegenerative disease that shares similar pathological characteristics with the process of normal aging (i.e., reduced dopamine), but to a much higher degree. In addition to investigating the effect of normal aging, the current study also examined the effect of “abnormal aging” on emotion and driving using PD as a model (aim 3).

Participants included 16 older (65 - 79 years old), 16 middle-aged (38 - 55 years old) neurologically normal adults, and 16 patients with mild PD (56 - 80 years old). This study focused on fear and anger, the two negative emotions that are most likely to be elicited by driving experiences and to disrupt driving behaviors. Low-level and high-level fear and anger challenges were created using simulated driving scenarios: 1) Low fear task, participants drove in fog and frequently encountered static obstacles on the road; 2) High fear task, participants drove at nighttime and frequently encountered deer running across the road; 3) Low anger task, participants drove following a slow-moving vehicle; 4) High anger task, participants followed a slow vehicle and were honked at by a tailgating vehicle. Participants rated the intensity of fear and anger experiences at 1- minute intervals when they were driving.

Comparing older adults against middle-aged adults, it was found that 1) fear intensity was lower in older adults in the low fear task. In contrast, latency and duration of fear were similar between groups in both fear tasks. 2) Anger intensity was lower in older adults in both anger tasks. Anger latency and duration were similar between groups in the high anger task, but anger took longer to develop and was of shorter duration in older adults in the low anger task. 3) In the low fear task, older adults exhibited more cautious driving behaviors (e.g., more frequent uses of brake). In the high anger task older adults were less able to control the acceleration and brake pedals smoothly (e.g., higher forces for brake and acceleration). These results suggest that age differences in the dynamic processes of emotion and the effect of emotion on driving may depend on the type of emotion and level of emotional challenge.

When comparing PD patients against age- and education-matched neurologically normal participants (n = 18), it was found that the PD patients reported experiencing similar degrees of fear and anger as the normal comparisons. However, in the high fear task PD patients were less responsive to deer running across the road (e.g., mean and variation of force for brake was lower in PD patients). This finding suggests an impaired ability in PD patients to respond to the sudden appearance of driving hazards.

Collectively, the findings of this study provide a window into how the moment-to-moment experience of negative emotions in response to environmental challenges may contribute to the overall emotional well-being of older adults. They also suggest that both the type of emotion and the level of challenge may be important factors in determining the experience of emotion and the effect of emotion on driving during “normal” and “abnormal” aging.

Public Abstract

Fear and anger may interfere with human behaviors. In critical situations such as automobile driving, the consequence of the emotions could be serious even fatal. My dissertation examined age-related changes in 1) the experience of fear and anger, and 2) the effect of fear and anger on driving. I studied normal older adults and patients with Parkinson’s Disease (PD), an age-related neurodegenerative disorder. I used driving simulation to create various anger- and fear-inducing situations. I found: 1) older adults experienced lower intensity of anger than middle-aged adults. 2) The time that fear developed and sustained was similar in older and middle-aged adults. 3) Age differences in the time that anger developed and sustained, and the intensity of fear might depend on the difficulty level of the situation. 4) Older adults drove more cautiously in a fear condition; however, in an anger condition they were less able to control the pedals smoothly compared to middle-aged adults. 5) PD patients experienced similar degrees of fear and anger as those without the disease. 6) In a fear condition involving driving at nighttime with deer crossing the road, PD patients exhibited lower responsiveness to deer. These results suggest that older age may associate with changes in fear and anger experiences. Aspects of emotion (intensity versus duration) and difficulty level of the situation may be important factors. PD may not affect the experience of fear and anger but may associate with increased risk of unsafe driving in situations with sudden driving hazards.

Keywords

publicabstract, Aging, Driving Simulation, Emotion, Parkinson's Disease, Psychophysiology

Pages

xvi, 213 pages

Bibliography

Includes bibliographical references (pages 169-213).

Copyright

Copyright 2015 Kuan-Hua Chen

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