Poster 11: Striatal Volume Distinguishes Converters from Non-Converters: Findings from PREDICT-HD

Results and Discussion After correcting for intracranial volume (ICV), converters had significantly smaller total brain volume ( p = 0.001), total white matter volume ( p = 0.004), and total striatum volume ( p < 0.0001), but did not differ on size of cerebellum. A logistic regression model was performed with age and gender included first, with the model selecting the remaining variables one by one. The ratio of striatum/ICV was the only variable selected yielding significant discrimination between converters and non-converters ( p < 0.0001), with correct classification of 78.2% of participants. None of the other MRI measures provided additional significant predictive value to the model. Results indicate that striatal volume, as assessed on MRI, but not other brain measures examined, contributes additional information beyond age and CAG repeat length in predicting onset of diagnosable HD signs. This information, assuming replication in larger samples, highlights the importance of striatal atrophy in the neurobiology of HD, and will be useful for designing clinical trials in which diagnosis of HD is the primary outcome measure.