Task-switching abilities in pre-manifest Huntington's disease subjects

Area of Science:

• Neuroscience
• Cognitive Science
• Genetics

Background:

• Huntington's Disease (HD) is a neurodegenerative disorder.
• Cognitive deficits, including executive functioning impairments, precede motor symptoms in HD.

Purpose of the Study:

• To investigate executive control deficits in pre-manifest Huntington's Disease (pre-HD) using a task-switching protocol.
• To assess if task-switching abilities change as pre-HD subjects approach motor symptom onset.

Main Methods:

• Recruited 30 pre-HD subjects and 18 healthy controls (HC).
• Assigned pre-HD subjects into two groups based on motor score (pre-HD1: TMS ≤4, pre-HD2: 5 ≤ TMS ≤9).
• Utilized a task-switching protocol with rapid, random task alternations to measure switch costs (SC) and reaction times.

Main Results:

• Pre-HD subjects exhibited significantly worse performance than HC, with increased SC and reaction times.
• Pre-HD2 subjects, closer to motor onset, showed more pronounced impairments in switching abilities compared to pre-HD1 and HC.

Conclusions:

• Task-switching deficits are detectable in the pre-manifest stage of Huntington's Disease.
• These cognitive impairments worsen as subtle motor signs emerge, even before a clinical diagnosis is possible.
• Early cognitive rehabilitation targeting executive functions may benefit individuals in the pre-manifest stage of HD.