Preliminary evidence of functional compensation in premanifest Huntington’s disease using a novel visuospatial working memory task

Abstract

Evidence suggests that presymptomatic-HD individuals are able to recruit additional brain regions in non- task related regions and/or increase cortical activity in task-specific networks during task performance. This has been attributed to an early compensatory response. Despite the evidence, no study to date has explicitly characterised compensation in HD. In this study, we used a quantitative model of compensation, known as the CRUNCH (Compensation-Related Utilization of Neural Circuits Hypothesis), to characterise compensation in HD using functional magnetic resonance imaging (fMRI). The CRUNCH model postulates that cortical activity increases as task difficulty increases, to compensate for task difficulty. However, when individuals reach their maximum load capacity (usually at higher levels of difficulty), they exhibit less corti- cal activity and typically performance declines.