Normative Modeling of Brain Structure Deviations in Parkinson’s Disease Patients without Dementia

Motivation: Cortical alterations in Parkinson's disease (PD) patients remain inconsistent. Goal(s): This study aimed to determine the structure of cortical deviations in PD without dementia.. Approach: Individualized centile scores for brain structure in 225 PD patients without dementia were derived from lifespan brain charts, and adjusted with a local sample of 451 healthy controls. Results: 44% of cortical regions showed negative deviations, while the remaining regions displayed preservation in PD patients without dementia. PD patients showed negative deviations in gray matter volume, positive deviations in CSF volume, and no deviations in white matter volume. Cortical thickness was linked to the severity of gait freezing. Impact: PD patients without dementia exhibit heterogeneous cortical changes, with nearly half showing negative deviations. Global alterations include reduced gray matter, increased cerebrospinal fluid (CSF), and stable white matter volume (WMV). Thinner cortical thickness correlates with more severe gait freezing.