Intellectual curiosity and action initiation are subtypes of apathy affected in Huntington’s disease gene expansion carriers

Abstract

AbstractBackgroundApathy is a prevalent behavioral symptom in neurodegenerative diseases. In Huntington’s Disease, apathy can result in severe loss of function for the patient and substantial caregiver distress. The research‐based evidence of apathy is characterized by a lack of generalizability due to methodological differences. In this study we wished to characterize apathy in premanifest and motor‐manifest Huntington’s Disease gene expansion carriers and controls.Method82 Huntington’s Disease gene expansion carriers (premanifest and motor‐manifest) and 32 controls were included in the study (Mini‐Mental State Examination score ≥ 24 and Montreal Cognitive Assessment score ≥ 19). Apathy was quantified using the Lille Apathy Rating Scale and the Short Problem Behaviors Assessment for Huntington’s Disease. Analyses of association were performed between apathy on the Lille Apathy Rating Scale and motor function, cytosine‐adenine‐guanine repeat length, cytosine‐adenine‐guanine age product score, neuropsychiatric and cognitive screening tests.ResultCompared to premanifest and control participants, the motor‐manifest Huntington’s Disease gene expansion carriers scored significantly higher on the global score on the Lille Apathy Rating Scale and on two subscales (Intellectual Curiosity and Action Initiation – see table 1). Likewise, motor‐manifest HD gene expansion carriers scored significantly higher on the Short Problem Behaviors Assessment for Huntington’s Disease. Significant correlations were found between apathy on the Lille Apathy Rating Scale and the motor score, the neuropsychiatric measures and the cognitive screening tests. Apathy was present in 22 % of the Huntington’s Disease gene expansion carriers (including four premanifest participants) when examined with the Lille Apathy Rating Scale. The apathetic participants had significantly higher motor score and were significantly affected on the neuropsychiatric measures and the cognitive screening tests. When entered a multiple stepwise regression model, apathy was predicted by the motor score and the depression score. No other variables could significantly predict apathy on the Lille Apathy Rating Scale.ConclusionApathy is a frequent and early symptom of disease in Huntington’s Disease gene expansion carriers, and it has a specific expression that might be related to the underlying neuropathology. Apathy is related to disease progression, cognitive decline and neuropsychiatric symptoms.