Practice effects as a dynamic biomarker of early cognitive change in far-from-onset Huntington’s disease

Although cognitive performance typically appears preserved in far-from-onset Huntingtin Gene Expansion Carriers (HGECs), underlying neuropsychological mechanisms may be subtly altered and remain undetected. Practice effects from repeated task exposure provide a sensitive measure of cognitive adaptability, with early disruptions signaling reduced neural efficiency before standard deficits emerge. This study aimed to examine longitudinal practice effects across annual neuropsychological testing in far-from-onset HGECs and to identify the disease burden threshold where these patterns diverge.