A-095 Processing Speed Indicators in Juvenile Huntington’s Disease: Assessing CAG Repeat, Age of Onset, and Mood

Abstract

Abstract Objective In adult onset Huntington’s Disease (HD), processing speed deficits and depression can be detected in the prodromal stages. These factors, along with CAG repeat length, may be predictive of age of symptom onset. However, less is known about the relationship between the aforementioned factors for patients diagnosed with Juvenile Huntington’s Disease (JHD). The current study aimed to investigate the relationships between age of symptom onset, CAG repeat, processing speed, and mood to improve prediction of symptom manifestation for JHD patients. Method Data was analyzed from the Kids HD study and included 30 participants (age at diagnosis M = 13.6, SD = 5.4, CAG repeat mean = 69, SD = 16). Bivariate partial correlations, independent t-tests, and regression analyses examined differences in processing speed across CAG repeat, age of onset, and depressive symptomology. Results CAG repeat length significantly predicted the natural log of age at diagnosis, β = −.59, t(25) = −3.59, p < .01, and significantly explained variance in the natural log of age at diagnosis, R2 = .35, F(1, 25) = 12.86, p < .01. Finally, results indicated that CAG repeat length also predicted processing speed abilities when controlling for depressed mood symptomology, R2 = .39, F(3,24) = 5.18, p < .01. Conclusion CAG repeat length holds predictive power for the age of diagnosis and for processing speed, even when accounting for covariate depressive mood indicators. Overall, results indicate evidence of impacted processing speed abilities given expansive CAG repeat numbers. This is consistent with a subcortical neurodegenerative process, such as HD.