Neurophysiological, Behavioral, and Cognitive Networks in Movement Disorders
Neurophysiological, Behavioral, and Cognitive Networks in Movement Disorders
The purpose of this study is to investigate the brain activity associated with motor and
 non-motor symptoms of movement disorders, including Parkinson's disease (PD) and essential
 tremor. These movement disorders commonly have significant non-motor features, such as
 depression, cognitive and memory impairment, decreased attention, speech and language
 disturbances, and slower processing speeds. The investigators are interested in the brain
 activity associated with these motor and non-motor symptoms, and propose to investigate
 changes in brain activity while the investigators perform recordings of the surface and deep
 structures of the brain, in addition to the typical recordings the investigators perform,
 during routine deep brain stimulation (DBS) surgery.
Movement disorders are a prominent cause of disability worldwide. In the United States, it is
 estimated that more than 4 million people suffer from Parkinson's disease (PD), essential
 tremor (ET), and dystonia, making them some of the most prevalent of neurologic disorders. Of
 these, PD is the most common, and is primarily characterized by tremor, rigidity, and
 bradykinesia. However, though primarily characterized by motor symptoms, many patients also
 have prominent non-motor features, including depression and cognitive impairment, with
 deficiencies in processing speed, memory, attention, and learning. Some of the most
 debilitating cognitive deficiencies include deficits in goal-directed response selection and
 response inhibition, language, and/or speech difficulties, all of which substantially
 contribute to reduced quality of life.

 Unfortunately, these features of movement disorders are less well-studied and lack effective
 treatment options, necessitating that new treatments be investigated. Deep brain stimulation
 (DBS), while a highly effective treatment for the cardinal features of PD, is essentially
 ineffective for, and can even worsen other cognitive domains, and there are few studies
 currently investigating how different parameters of DBS may improve these symptoms. In
 addition, speech abnormalities are common with Parkinson's disease and DBS can sometimes
 worsen speech problems. These impairments consists primarily of hypophonia, but cognitive
 deficits can result in actual language disturbance. It is often difficult to know whether the
 speech problems are related to language processing or articulation (related to the movement
 disorder). In an effort to begin addressing these questions, we propose to study motor and
 non-motor symptoms in patients with movement disorders, and to correlate movement and
 cognition with underlying neural electrophysiology.
Inclusion Criteria:

 -  Eligible for DBS surgery based on multi-disciplinary consensus review

 -  Have a diagnosis of Parkinson's disease or Essential Tremor

 -  A minimum of 18 years of age

 -  Willingness to participate in the paradigms described in the protocol

 Exclusion Criteria:

 -  Inability to provide full and informed consent

 -  Are not surgical candidates due to co-morbid conditions or pregnancy

 -  Have not undergone an adequate trial of conservative medical management

 -  Have a clinical presentation for which DBS surgery is not indicated

 -  Are not able to participate in study-related activities