Daily Amino Acid Supplementation for People With Parkinson's Disease

Body composition will be assessed using a multi-spectral bioelectrical impedance (Mediana i55, Mediana, South Korea). During this test participants will clean their feet and hands using a sanitary wipe and then stand barefoot on the impedance machine while holding two electrodes. Then a small and imperceivable multi-spectral electrical current will be sent between limbs which the machine will use to estimate the fat content and distribution based on the resistance (i.e., impedance) of this current.

A trained (>20 hr. logged research scanning) ultrasound researcher will use an ultrasound (ACUSON Sequoia, Siemens Healthineers, USA) to assess muscle thickness of the primary knee extensors (quadriceps femoris) and the plantar flexors (gastrocnemius and soleus) as well as their tendons. Longitudinal panoramic 2D ultrasound will be used to measure muscle fascicle length and angle of each muscle. To assess tissue composition of these muscles shear-wave elastography will be used to measure localized muscle stiffness based on propagation of a concentrated acoustic shear (push-pull) wave applied to the center of the muscle.

Participants will be sent a research-grade activity monitor, Actigraph GT9X device, in the standard mail at their residence. After receiving the device, participants will engage in a telephone or virtual meeting with a research assistant to learn how to use the device. (approximately 30-40 minutes). Participants will be asked to wear the activity monitor for 7 days prior to the first baseline visit. They will be asked to continuously wear the device on their wrist for the 7 days. Participants will return the device in a pre-paid envelope. The same procedure will occur at the conclusion of the intervention for a post-intervention assessment.

This test assesses balance impairments across 14 items consisting of dynamic balance, anticipatory postural adjustments, reactive postural control, sensory orientation and dynamic gait. The total score ranges from 0 to 28, with each item scored on a scale from 0 to 2 with higher scores indicating better balance.

This physical test measures the speed at which a person can walk for 4 meters which is related to overall functional ability. The patient is asked to walk at normal speed for 4 meters, while the evaluator records the time required for it. The gait speed is calculated dividing the distance (4m) by the time completed by the participant. The fastest of 2 trials is then recorded.

This test measures the speed at which a person can walk for 10 meters. The participant will walk for 10 meters, divided by 2 initial meters of acceleration and 2 final meters for deacceleration. The walking speed during the central 6 meters is then recorded.

The Five Times Sit to Stand Test is a physical test for measuring functional strength in the lower limbs. For this test, the participant must stand up and sit down on an armless chair with their arms crossed on their chest as fast as possible 5 times. A practice trial is permitted before the test trial.

Bilateral grip strength will be assessed with the use of a handheld dynamometer. For this test the participant must be seated on a chair, with the assessed limb at 90º of elbow flexion and holding the dynamometer in a neutral wrist position. Two sub-maximal trials at 50% and 70% of the Maximal voluntary Isometric grip contraction will be performed as a warmup. Then, 3 maximal trials separated by 1 minute of rest will be performed. If there is a 5% or bigger difference in strength for any trial, a fourth attempt must be completed. The highest value obtained for each limb is recorded.

In these tests participants will be seated in an isometric dynamometer (Biodex System 4, Biodex, USA) with their body and dynamometers positioned according to manufacturer instructions. In these positions participants will perform three submaximal practice isometric contractions (~25%, 50%, and 75% maximal effort) and then 5 maximal effect isometric contractions with each contraction separated 1 min of rest.

This questionnaire assesses the difficulties that people with PD experience across 8 dimensions of daily living; Activities of Daily Living, Attention \& Working Memory, Cognition, Communication, Depression, Functional Mobility, Quality of Life, Social Relationships and Social Support. The score ranges from 0-100 with higher scores indicating worse quality of life.

This is a 16-Item patient-rated questionnaire that quantifies fatigue in people with PD. The scores range from 16 to 80 with higher scores indicating higher levels of fatigue.

This is a patient-reported questionnaire that assess nighttime sleep across 5 items in patients with Parkinson's disease. The score ranges from 0-15 with higher scores indicating worse sleep.

This is a patient-reported questionnaire that assess daytime sleepiness across 6 items in patients with Parkinson's disease. The score ranges from 0-18 with higher scores indicating more daytime sleepiness.

This is a patient-reported questionnaire that assess the individual's global assessment of nighttime sleep with one item in patients with Parkinson disease. The score ranges from 0-6 with higher scores indicating worse global sleep quality.

This an assessment of current mood state. It is a 40-item self-report survey that evaluates the degree to which a participant is feeling a selected emotion at the moment. The score ranges from -30 to 200 with higher scores indicating worse mood.

This is an assessment of somatic and cognitive symptoms of anxiety. It consists of 21 items in the form of self-reported questionnaire. The score ranges from 0-63 with higher scores indicating higher levels of anxiety.

This is the most used measure of motivators for exercise. It is a 19-item survey that evaluates the stages of motivation to exercise. This includes amotivation, external regulation, introjected regulation, identified regulation, and intrinsic regulation. The score ranges from -24 to +20 with higher scores indicating increased motivation.

This is a 15-item self-report measure of depression in older adults. Scores range from 0-15 with higher scores indicating more severe depression.

Blood drawn will be used to analyze blood glucose. A test strip will be inserted into a glucose meter and a small sample of blood will be applied. The blood glucose level will be recorded.