Date of Award


Document Type


Degree Name

Master of Arts in Psychological Science



First Reader/Committee Chair

Jones, Jacob


Parkinson's Disease (PD) is a neurodegenerative disease characterized by motor (e.g. tremors) and non-motor symptoms (e.g. cognitive impairment). PD patients' change in cognitive functioning can be observed using the following classifications: cognitively intact, mild cognitive impairment (MCI), or dementia (PDD). MCI has many subtypes, one of which is MCI reversion which is defined as those with MCI at one time point reverting to cognitively intact later. While there is limited research into the utility of MCI reversion and its relationship with cerebrospinal fluid (CSF) biomarkers in PD, this study will begin to elucidate this relationship. To this end, data from 393 de novo PD patients was obtained from the Parkinson's Progression Markers Initiative (PPMI) for the first 3 years. MCI was determined if the patient's scores fell 2 standard deviations below 2 or more neuropsychological assessments. CSF biomarker samples included beta-amyloid, total tau, phosphorylated tau, and alpha-synuclein, and were analyzed using an enzyme-linked immunosorbent assay (ELISA). Multilevel modeling was used to examine the association between CSF biomarker ratios and cognitive functioning status (cognitively intact, MCI converters, MCI stable, and MCI reverters) longitudinally. MCI reverters did not differ significantly from those who were cognitively intact. There was a main effect of MCI converters in the tau ratio compared to CI patients and there was a group-by-year interaction with yearly increases in asyn in the MCI stable group. Findings support MCI reverters do not differ from cognitively intact individuals on biomarkers associated with cognitive decline in PD. These findings suggest MCI reversion may not be clinically meaningful; however, between alternative approaches and confounds, more research is needed.