Cognitive Dysfunction in Parkinson's Disease

Dementia is the leading cause of nursing home placement in Parkinson's disease (PD) yet
little is known about the cause(s) of cognitive dysfunction in PD and there are no effective
treatments. The investigators preliminary data and other published studies suggest that
abnormalities in brain activity involving networks important for normal thinking and memory
may contribute to cognitive dysfunction in PD and may represent a target for treatment. This
proposal will identify abnormalities in cortical activity related to cognitive dysfunction in
PD using magnetoencephalography and will perform a randomized control trial of bifrontal
repetitive transcranial magnetic stimulation to determine the therapeutic potential of
modulating this brain activity.

Inclusion Criteria:

- Diagnosis of probable PD (using United Kingdom Brain Bank criteria)

- Diagnosis of mild cognitive impairment

- No unstable medical condition

Exclusion Criteria:

- Features suggestive of other causes of Parkinsonism or other neurological disorders

- Prior deep brain stimulation (DBS) or ablation surgery

- Evidence for active depression or Hospital Anxiety and Depression Scale (HADS) score
greater than or equal to 11

- Motor symptoms expected to interfere with scanning (e.g. sever tremor)

- Contraindications to TMS, MEG, or MRI such as pregnancy, pacemaker, unstable cardiac
disease, skull lesion, claustrophobia, history of epilepsy, or on medications known to
lower seizure threshold

- Implanted electronic devices or metal