Parkinson's Disease Cognitive Phenotypes Show Unique Clock Drawing Features when Measured with Digital Technology

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• A prior study detailed neuroimaging and neuropsychological profiles of Parkinson's disease (PD) without dementia.
• This research builds upon that by examining subtle behavioral differences in PD using digital clock drawing.

Purpose of the Study:

• To compare digital clock drawing performance (latency and graphomotor metrics) between individuals with PD and non-PD peers.
• To investigate how digital clock drawing metrics differentiate cognitive phenotypes within the PD cohort (low executive, low memory, cognitively well).

Main Methods:

• 230 participants (115 PD, 115 non-PD) completed neuropsychological tests and the digital Clock Drawing Test (dCDT).
• PD participants were categorized into cognitive phenotypes: PD low executive (PDExe), PD low memory (PDMem), and PD cognitively well (PDWell).
• Bayesian analysis compared groups on total completion time (TCT), pre-first hand latency (PFHL), post-clock face latency (PCFL), total clock face area (TCFA), and pen strokes.

Main Results:

• Fewer pen strokes and slower performance during command drawing correlated with higher odds of PD diagnosis.
• A larger clock face during the copy condition was associated with lower odds of PD diagnosis.
• Within PD phenotypes, slower performance and smaller clock faces during command drawing were linked to PDExe compared to PDWell; larger clock faces were linked to PDMem compared to PDWell.

Conclusions:

• Digital clock drawing provides distinct performance profiles differentiating individuals with PD from their non-PD counterparts.
• Digital clock drawing metrics effectively distinguish between different cognitive phenotypes within Parkinson's disease.