Apathy and Functional Status in Early-Stage Huntington's Disease.

Objective: Apathy is common in Huntington's disease (HD) and difficult to treat. Multiple recent calls have been made to increase understanding of apathy across the spectrum of HD severity. Functional status is an important outcome in HD trials; however, no consensus currently exists regarding the impact of apathy on functional status in HD. The authors aimed to identify correlates of apathy and effects on functional status in a primarily early-stage HD sample.

Methods: This study included secondary analyses of data from a study of neuropsychiatric symptoms in a clinical HD sample. Spearman correlation analyses were used to assess the relationships between apathy (with the Frontal Systems Behavior Scale-Apathy [FrSBe-Apathy] subscore), clinical variables, and patient-reported outcomes. To assess the association of apathy with functional status, two multiple regression analyses were performed, with a different functional status measure (Adult Functional Adaptive Behavior [AFAB] scale or Total Functional Capacity [TFC] scale) as the dependent variable in each analysis.

Results: Statistically significant correlates of apathy included the Quality of Life in Neurological Disorders (Neuro-QoL) Satisfaction With Social Roles and Activities and Neuro-QoL Positive Affect and Well-Being scores (N=70 patients). Univariate correlation analyses also revealed statistically significant associations of FrSBe-Apathy scores with both functional status measures. In the multiple regression analyses, apathy significantly contributed to variability in functional status as measured by both the AFAB (N=49 patients) and TFC (N=56 patients) scales.

Conclusions: These results underscore the need to address apathy as a target for improving functional status, social satisfaction, and well-being in HD, even for individuals with early-stage HD.