Determine 1) the magnitude of SMG and skin a-syn density change over time, 2) the
improvement in adequate tissue acquisition doing bilateral SMG biopsies, 3) any laterality differences between
SMG gland a-syn density, 4) correlate a-syn density and changes in density between SMG and skin biopsies
Specific Aim 1. Determine, with bilateral submandibular gland (SMG) biopsies in 30 clinically
diagnosed subjects with Parkinson’s disease (PD) and 20 clinically probable REM sleep behavior
disorder (RBD) subjects whether bilateral biopsies improve the rate of acquisition of adequate
glandular tissue, whether alpha-synuclein (a-syn) SMG pathology correlates with clinical severity
and/or disease duration, and whether there is a left-right difference in the density of a-syn pathology.
Specific Aim 2. Determine, with a second SMG biopsy in previously biopsied PD and RBD subjects,
whether a-syn pathology density increases, decreases, or remains the same after a 1.5-2 year time
interval and whether there is a correlation between a-syn SMG pathology and clinical and/or disease
progression.
Specific Aim 3. Determine whether a-syn pathology density in skin punch biopsies correlates
with clinical measures and increases, decreases, or remains the same after a 1.5-2 year time
interval, and whether the density and changes over time correlate with those found in SMG
biopsies.