Friday, July 09, 2010

iPost: Self-paced mental timing used to Dx and track progress of Huntington disease

Self-paced timing detects and tracks change in prodromal Huntington disease.

By Rowe, Kelly C.; Paulsen, Jane S.; Langbehn, Douglas R.; Duff, Kevin; Beglinger, Leigh J.; Wang, Chiachi; O'Rourke, Justin J. F.; Stout, Julie C.; Moser, David J.
Neuropsychology, Vol 24(4), Jul 2010, 435-442.
Objective: This study compares self-paced timing performance (cross-sectionally and longitudinally) between participants with prodromal Huntington's disease (pr-HD) and a comparison group of gene non-expanded participants from affected families (NC). Method: Participants (747 pr-HD: 188 NC) listened to tones presented at 550-ms intervals, matched that pace by tapping response keys and continued the rhythm (self-paced) after the tone had stopped. Standardized cross-sectional and longitudinal linear models examined the relationships between self-paced timing precision and estimated proximity to diagnosis, and other demographic factors. Results: Pr-HD participants showed significantly less timing precision than NC. Comparison of pr-HD and NC participants showed a significant performance difference on two task administration conditions (dominant hand: p < .0001; alternating thumbs: p < .0001). Additionally, estimated proximity to diagnosis was related to timing precision in both conditions, (dominant hand:t = −11.14, df = 920, p < .0001; alternating thumbs:t = −11.32, df = 918, p < .0001). Longitudinal modeling showed that pr-HD participants worsen more quickly at the task than the NC group, and rate of decline increases with estimated proximity to diagnosis in both conditions (dominant hand: t = −2.85, df = 417, p = .0045; alternating thumbs: t = −3.56, df = 445, p = .0004). Effect sizes based on adjusted mean annual change ranged from −0.34 to 0.25 in the longitudinal model. Conclusions: The self-paced timing paradigm has potential for use as a screening tool and outcome measure in pr-HD clinical trials to gauge therapeutically mediated improvement or maintenance of function.

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