Blood Flow Restriction for Optimizing Balance in Parkinson's Disease

The treatment will be considered acceptable if the dropout and significant adverse event rate is less than 20%, that is no more than 2 out of 10 participants in the treatment group either 1) drop out, 2) withdraw consent, or 3) have a significant adverse event (Grade 3 or higher on 5 point scale where 1 = mild, 2 = moderate, 3 = severe, 4 = life threatening, and 5 = death). Results will be reported as percentage of participants that dropped out.

Balance will be measured using the miniBESTest Balance Evaluation Systems Test. The test has a range of scores from 0 to 28 points from 14 items that are each scored from 0-2.

"0" indicates the lowest level of function and "2" the highest level of function. Equipment used: Temper® foam (also called T-foamTM 4 inches thick, medium density T41 firmness rating), chair without arm rests or wheels, incline ramp, stopwatch, a box (9" height) and a 3 meter distance measured out and marked on the floor with tape [from chair].

The 30-second chair stand (30CST) will be used to assess functional mobility. In this test a person needs to stand up from sitting as many times as possible in 30 seconds. An increase in the number of stands is suggestive of better lower extremity strength

Motor severity will be assessed by the Movement Disorders Society - Unified Parkinson's Disease Rating Scale - part III. This scale is the gold standard for measuring the severity and progression of PD. Part III entails motor examination which consists of 18 questions that are scored on a 0-4 scale with a total score range between 0 and 72. Higher scores suggest greater severity and progressing disease.

Participants will perform postural sway assessments on the Biodex BioSway. Participants will maintain a consistent foot position which will be recorded and kept constant for all trials. Change in postural stability will be compared from baseline to follow up assessments.

Spinal reflex excitability will be measured by eliciting the H-reflex. Subjects will lay down in a prone position. Surface recording electrodes will be placed over the soleus muscle. The tibial nerve will be stimulated with a nerve stimulator. The reference electrode would be placed over the knee cap. Once stimulation electrodes are positioned, H-reflex and M-wave recruitment curves will be obtained. Stimulus intensity will be increased every 5 seconds by 2 mA increments until the maximum H-reflex (Hmax) is obtained and then increased by 10 mA increments until the maximal M response is obtained (Mmax). The M-wave target amplitude will be monitored to ensure stability of stimulation throughout the experiment while eliciting an H-reflex recruitment curve. The H wave amplitude will be expressed as a % of the Mmax (maximum M wave) amplitude.

Muscle strength for hip abductors will be measured with isokinetic dynamometry.

Muscle strength for knee extensors will be measured with isokinetic dynamometry.

Muscle strength for ankle plantar flexors will be measured with isokinetic dynamometry.

The Parkinson's Disease Questionnaire (PDQ)-39 is a widely used tool for evaluating quality of life in PD. It consists of 39 items that cover seven domains such as mobility, activities of daily living, emotional well-being, stigma, social support, cognition, and communication. Scores on each item range from 0-4 with 0 indicating never and 4 indicating always. These scores are converted to a summary index score which ranges from 0 - 100, with lower scores suggesting higher quality of life.