Huntington's Disease and Employment: The Relative Contributions of Cognitive and Motor Decline to the Decision to Leave Work.

Background: Huntington's disease (HD) presents with motor, cognitive, and behavioral symptoms that impair functional capacity and the ability to maintain employment. The relative contribution of cognitive decline to work disability remains controversial.
Objective: To evaluate the association of cognitive decline, compared with motor decline, with the decision to leave work.
Methods: Data from the Enroll-HD observational study were analyzed. The correlation of age of cognitive symptom onset and age of motor symptom onset with age at leaving work was assessed. The association of the Stroop Color Naming Test (SCNT) cognitive assessment and the Total Motor Score (TMS) assessment (reverse scored) with the Total Functional Capacity (TFC) assessment was also assessed.
Results: For every year delay in cognitive symptom onset, there was a 0.806 year increase in age at leaving work (SE = 0.030, p < 0.001, adj-R2 = 0.628). For every year delay of motor symptom onset, there was a 0.814 year increase in age at leaving work (SE = 0.031, p < 0.001, adj-R2 = 0.603). For every additional correct SCNT response given and for every unit increase in TMS, there was a 0.105 unit increase (SE = 0.006, p < 0.001, adj-R2 = 0.315) and a 0.104 unit decrease in TFC (SE = 0.003, p < 0.001, adj-R2 = 0.640), respectively.
Conclusions: Cognitive symptoms have a significant association, comparable to that of motor symptoms, with occupational functioning and the decision to leave work, suggesting that development of therapies for both cognitive and motor decline would be important for allowing people with HD to remain in the workforce longer.