Startle reflex hyporeactivity in Parkinson's disease: an emotion-specific or arousal-modulated deficit?
Neuropsychologia
; 47(8-9): 1917-27, 2009 Jul.
Article
in En
| MEDLINE
| ID: mdl-19428424
ABSTRACT
We previously reported that patients with Parkinson's disease (PD) demonstrate reduced psychophysiologic reactivity to unpleasant pictures as indexed by diminished startle eyeblink magnitude [Bowers, D., Miller, K., Bosch, W., Gokcay, D., Pedraza, O., Springer, U., et al. (2006). Faces of emotion in Parkinsons disease Micro-expressivity and bradykinesia during voluntary facial expressions. Journal of the International Neuropsychological Society, 12(6), 765-773; Bowers, D., Miller, K., Mikos, A., Kirsch-Darrow, L., Springer, U., Fernandez, H., et al. (2006). Startling facts about emotion in Parkinson's disease Blunted reactivity to aversive stimuli. Brain, 129(Pt 12), 3356-3365]. In the present study, we tested the hypothesis that this hyporeactivity was primarily driven by diminished reactivity to fear-eliciting stimuli as opposed to other types of aversive pictures. This hypothesis was based on previous evidence suggesting amygdalar abnormalities in PD patients, coupled with the known role of the amygdala in fear processing. To test this hypothesis, 24 patients with Parkinson's disease and 24 controls viewed standardized sets of emotional pictures that depicted fear, disgust (mutilations, contaminations), pleasant, and neutral contents. Startle eyeblinks were elicited while subjects viewed these emotional pictures. Results did not support the hypothesis of a specific emotional reactivity deficit to fear pictures. Instead, the PD patients showed reduced reactivity to mutilation pictures relative to other types of negative pictures in the context of normal subjective ratings. Further analyses revealed that controls displayed a pattern of increased startle eyeblink magnitude for "high arousal" versus "low arousal" negative pictures, regardless of picture category, whereas startle eyeblink magnitude in the PD group did not vary by arousal level. These results suggest that previous findings of decreased aversion-modulated startle is driven by reduced reactivity to highly arousing negative stimuli rather than to a specific category (i.e., fear or disgust) of emotion stimuli.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Parkinson Disease
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Arousal
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Psychophysiologic Disorders
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Reflex, Startle
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Reflex, Abnormal
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Emotions
Limits:
Aged
/
Female
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Humans
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Male
/
Middle aged
Language:
En
Journal:
Neuropsychologia
Year:
2009
Document type:
Article
Affiliation country: