Clinical correlates and cognitive underpinnings of verbal fluency impairment after chronic subthalamic stimulation in Parkinson's disease.
A decline in verbal fluency is the most consistent neuropsychological sequela of deep brain stimulation (DBS) for Parkinson's disease. We assessed clinical correlates and switching and clustering subcomponents in 26 parkinsonians undergoing subthalamic DBS. Post-surgical motor improvement was accompanied by worsening at both letter and category fluency tasks. Total number of words and switches decreased, while average cluster size was unchanged. Worsening tended to be prominent in patients with baseline poorer cognitive status and more depressed mood. Impairment of shifting suggests prefrontal dysfunction, possibly due to disruption of fronto-striatal circuits along the surgical trajectory and/or to high frequency stimulation itself.
Department of Neuroscience, Center for Parkinson's Disease, Istituti Clinici di Perfezionamento, Milan, Italy.
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De Gaspari
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Siri
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Di Gioia
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Antonini
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Isella
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Pizzolato
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Landi
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Vergani
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Gaini
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Appollonio
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Pezzoli
D000368:Aged; D001479:Basal Ganglia / Q000601:surgery; D016000:Cluster Analysis; D003071:Cognition / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000009:adverse effects*; D003863:Depression / Q000523:psychology; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D009460:Neurologic Examination; D019635:Neurosurgical Procedures; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology / Q000628:therapy*; D013064:Speech Disorders / Q000209:etiology* / Q000523:psychology; D020530:Subthalamus / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*