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Deep brain stimulation (DBS) of the subthalamic nucleus markedly improves the motor symptoms of Parkinson's disease, but causes cognitive side effects such as impulsivity. We showed that DBS selectively interferes with the normal ability to slow down when faced with decision conflict. While on DBS, patients actually sped up their decisions under(More)
It takes effort and time to tame one's impulses. Although medial prefrontal cortex (mPFC) is broadly implicated in effortful control over behavior, the subthalamic nucleus (STN) is specifically thought to contribute by acting as a brake on cortico-striatal function during decision conflict, buying time until the right decision can be made. Using the drift(More)
Subthalamic nucleus deep brain stimulation improves motor symptoms and quality of life in advanced Parkinson's disease. As after other life-altering surgeries, suicides have been reported following deep brain stimulation for movement disorders. We sought to determine the suicide rate following subthalamic nucleus deep brain stimulation for Parkinson's(More)
We sought to define quantitative electroencephalographic (EEG) measures as biomarkers of both early and late cognitive decline in Parkinson's disease (PD). PD subjects classified as cognitively normal (PD-CogNL), mild cognitive impairment (PD-MCI), and dementia (PD-D) were studied. Cognitive status and neuropsychological testing was correlated with(More)
OBJECTIVE Recent studies show that deep brain stimulation can be performed safely and accurately without microelectrode recording ortest stimulation but with the patient under general anesthesia. The procedure couples techniques for direct anatomical targeting on MRI with intraoperative imaging to verify stereotactic accuracy. However, few authors have(More)
A new theoretical framework is used to analyze functions and pathophysiological processes of cortico-basal ganglia-thalamocortical loops and to demonstrate the hierarchical relationships between various loops. All hierarchical levels are built according to the same functional principle: Each loop is a neural optimal control system (NOCS) and includes a(More)
BACKGROUND/AIMS Previously we have shown that functional declines in Parkinson's disease (PD) and Alzheimer's disease (AD) correlate to global measures of cognitive decline. We now determine if the correlation between cognitive impairment and functional ability in PD is similar to that in AD using individual cognitive measures. METHODS 93 PD subjects and(More)
Dysphagia is very common in patients with Parkinson disease (PD) and often leads to aspiration pneumonia, the most common cause of death in PD. Current therapies are largely ineffective for dysphagia. Because pharyngeal sensation normally triggers the swallowing reflex, we examined pharyngeal sensory nerves in PD patients for Lewy pathology.Sensory nerves(More)
Classical conditioning is abnormal in patients with cerebellar degeneration. Pathological studies have recently demonstrated the finding of Purkinje cell loss in a subset of essential tremor (ET). We studied 10 subjects with long duration ET using a blink reflex conditioning paradigm and compared them with nine controls. A 55.6% reduction in motor learning(More)