Evidence of thalamic dysfunction in Huntington disease by proton magnetic resonance spectroscopy.

Our objective was to investigate thalamic neuronal dysfunction in patients with Huntington disease (HD). We performed localized single-voxel proton magnetic resonance spectroscopy (MRS) of the thalamus in 22 HD patients and 25 healthy individuals. The mean age of patients was 48.5 years (ranging from 32 to 71 years). Age at onset varied between 20 and 66 years (mean 38.9 years). The expanded CAG repeat ranged from 40 to 52 (mean 45.2) CAGs. The mean age of control group was 35.4 years, ranging from 19 to 67 years. N-acetylaspartate (NAA) relative to creatine (NAA/Cr) values in the thalamus of HD patients were decreased when compared with controls (P = 0.0001). The spectroscopic findings were not correlated with motor impairment. However, there was a positive correlation between duration of disease and motor impairment (P = 0.02, r = 0.48), and a tendency for positive correlation between duration of disease and NAA/Cr (P = 0.059, r = 0.4). We found decreased NAA/Cr values in the thalamus of patients with HD, indicating neuronal loss or dysfunction. This is in agreement with previous studies that indicated the involvement of mitochondrial dysfunction in the neurodegenerative process of HD.