Affiliations: [a] Department of Psychiatry, UC San Diego, La Jolla, CA, USA
| [b] Department of Neurosciences, UC San Diego, La Jolla, CA, USA
| [c] Department of Psychology, San Diego State University, San Diego, CA, USA
Correspondence:
[*]
Correspondence to: Michael P. Caligiuri, PhD, Department of Psychiatry (0603), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. E-mail: [email protected].
Abstract: Background:Prior studies have relied on conventional observer-based severity ratings such as the Unified Huntington’s Disease Rating Scale (UHDRS) to identify early motor markers of decline in Huntington’s disease (HD). Objective:The present study examined the predictive utility of graphomotor measures handwriting and drawing movements. Methods:Seventeen gene-positive premanifest HD subjects underwent comprehensive clinical, cognitive, motor, and graphomotor assessments at baseline and at follow-up intervals ranging from 9–36 months. Baseline graphomotor assessments were subjected to linear multiple regression procedures to identify factors associated with change on the comprehensive UHDRS index. Results:Subjects were followed for an average of 21.2 months. Three multivariate regression models based on graphomotor variables derived from a complex loop task, a maximum speed circle drawing task and a combined task returned adjusted R2 coefficients of 0.76, 0.71, and 0.80 respectively accounting for a significant portion of the variability in cUHDRS change score. The best-fit model based on the combined tasks indicated that greater decline on the cUHDRS was associated with increased pen movement dysfluency and stroke-stroke variability at baseline. Conclusion:Performance on multiple measures of graphomotor dysfluency assessed during the premanifest or prodromal stage in at-risk HD individuals was associated with decline on a multidimensional index of HD morbidity preceding an HD diagnosis.
