Cortical atrophic-hypometabolic dissociation in the transition from premanifest to early-stage Huntington's disease

Huntington's disease (HD) is a fatal neurodegenerative disorder with no effective treatment currently available. Although the pathological hallmark of HD is massive striatal atrophy, it has been suggested that cortical deterioration may concomitantly occur and play a major role in the patient's functional independence. Our objective was to characterize cortical structural and metabolic neurodegeneration in the transition from premanifest to early-stage Huntington's disease (HD).

Using a surface-based neuroimaging approach, we compared cortical thickness and intracortical FDG-PET uptake in 19 early-symptomatic HD patients with respect to 21 premanifest HD individuals.

Early-HD patients showed significant cortical atrophy and intracortical hypometabolism when compared to premanifest subjects (p < 0.05, corrected for multiple comparisons). However, whereas the atrophy pattern was restricted to precentral and parieto-occipital regions, a pronounced frontotemporal hypometabolism was observed. Importantly, structural changes correlated with motor and cognitive performance, and metabolic changes were associated with the presence and severity of apathy in this population, a core neuropsychiatric feature of this disorder.

Our findings reveal an asynchronous neuronal loss and metabolic compromise across the cerebral cortex in early HD. Hence, the use of structural and metabolic imaging indicators to characterize disease progression in this population should take into consideration the dissociation which occurs between cortical atrophy and hypometabolism.