Emotion and ocular responses in Parkinson's disease

• Published in: Neuropsychologia 2011-10, Vol.49 (12), p.3247-3253
• Main Authors: Dietz, J., Bradley, M.M., Okun, M.S., Bowers, D.
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Aged; Aged, 80 and over; Analysis of Variance; Arousal; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Emotion; Emotions - physiology; Eye movement; Eye Movements - physiology; Humans; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Organic mental disorders. Neuropsychology; Parkinson Disease - complications; Parkinson's disease; Photic Stimulation - methods; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychophysiologic Disorders - diagnosis; Psychophysiologic Disorders - etiology; Pupil; Pupil - physiology
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2011.07.029

► Previous study showed muted skin conductance response in Parkinson's patients. ► Skin conductance may be affected by peripheral autonomic dysfunction in PD. ► Pupil dilation was used as an alternative measure of emotional arousal in PD. ► Eye movements served as index of motivated behavior. ► PD group showed normal arousal but abnormal eye movements to emotional pictures. Parkinson's disease (PD) is a neurodegenerative disease that affects motor, cognitive, and emotional functioning. Previous studies reported reduced skin conductance responses in PD patients, compared to healthy older adults when viewing emotionally arousing pictures. Attenuated skin conductance changes in PD may reflect peripheral autonomic dysfunction (e.g., reduced nerve endings at the sweat gland) or, alternatively, a more central emotional deficit. The aim of the current study was to investigate a second measure of sympathetic arousal—change in pupil dilation. Eye movements, a motor-based correlate of emotional processing, were also assessed. Results indicated that pupil dilation was significantly greater when viewing emotional, compared to neutral pictures for both PD patients and controls. On the other hand, PD patients made fewer fixations with shorter scan paths, particularly when viewing pleasant pictures. These results suggest that PD patients show normal sympathetic arousal to affective stimuli (indexed by pupil diameter), but differences in motor correlates of emotion (eye movements).