The Effect of Electrode Implantation for Deep Brain Stimulation (DBS) on Brain Function Using Single Photon Emission Computed Tomography (SPECT) With Technetium-99m-ethyl Cysteinatedimer (Tc-ECD)

Exploring the Effect of Electrode Implantation for DBS on Brain Function During Rest and During Semantic Verbal Fluency Task Using SPECT With Tc-ECD

The goal of this study is to explore the effect of subthalamic nucleus (STN)-DBS surgery and stimulation in PD (Parkinson's disease) patients on regional cerebral blood (CBF) flow during cognitive task performance or at rest.

In this study subjects undergo SPECT scans for CBF mapping. PD patients before the surgery and healthy controls undergo two scans. PD patients after the surgery undergo four scans. PD patients who undergo two scans before the surgery, undergo only two scans after the surgery.

Uptake of Tc-ECD, a CBF radiotracer, is done in the following conditions:

• For PD patients before the surgery - during the performance of the semantic verbal fluency task or at rest (total of 2 scans).
• For PD patients after the surgery- during the performance of the semantic verbal fluency task or at rest, either at on-stimulation or off-stimulation condition (total of 4 scans). The stimulator is turned off by the neurologist for 10 min.
• PD patients before and after the surgery- during performance of the semantic verbal fluency task or at rest before the surgery and during performance of the semantic verbal fluency task or at rest after the surgery only at off-stimulation condition (Total of 4 scans).
• Healthy controls - during the performance of the semantic verbal fluency task or at rest (total of 2 scans).

Following the Tc-ECD injection, the subjects are scanned by Irix SPECT camera for 15min.

Scans are analyzed and the regional CBF is measured using imaging software. Statistical analysis is done to discover the effect of the surgery, stimulation and the disease on blood flow at rest and during task performance. In addition, differences between groups in number of words produced during the task are also statistically analyzed.

Inclusion Criteria:

• Progressive idiopathic PD
• For control group - age-matched to study groups

Exclusion Criteria:

• Progressive dementia or other psychiatric disorders
• Other neurological conditions
• Other physical disease
• Intolerance of "off stimulation" state
• Involuntary head motions
• Hearing deficits