Apathy is a common non-motor symptom of PD, characterized by decreased goal directed behavior. Apathy results in significant decline in functional abilities, caregiver burden, and increased costs of care. Motor phenotypes of PD are widely recognized (i.e., Postural Instability and Gait Difficulty [PIGD] and non-PIGD). It is unknown if distinct apathy profiles characterize motor PD phenotypes. DAS allows a multi-dimensional characterization of apathy (executive, emotional and cognitive/behavioral components) in addition to self-awareness.

Eighteen participants (9 women, mean age: 64.5±9.5 years) with PD were recruited at Baylor College of Medicine under an IRB approved protocol. Apathy was measured by the DAS (cut off = 28.5), completed by both, participants and caregivers. Participants were also assessed with the Movement Disorders Society’s-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) and the Montreal Cognitive Assessment (MoCA). Analyses were performed for the whole cohort and clinical subgroups (PIGD and non-PIGD). Statistical analyses were done by GraphPad Prism version9.0.

Seven participants were apathetic (PD-A) and 11 non-apathetic (PD-NA). There were no significant differences in age and MDS-UPDRS score between PD-A and PD-NA. The PD-A group had a significantly lower MoCA score (24.7±2.2 vs 27.4±2.5; p=0.03). In the whole cohort, there was a negative correlation between MoCA and total DAS score. DAS scores of participants and caregivers were correlated for the behavioral/cognitive and executive subscores but not for the emotional domain. Among those with PIGD-phenotype, 75% (3/4) had apathy versus 28.6% (4/14) among those with non-PIGD.