Proton MR spectroscopy in idiopathic spasmodic torticollis.

Single-voxel proton magnetic resonance spectroscopy (1H-MRS), localised to the basal ganglia, was used to determine changes in metabolite levels in idiopathic spasmodic torticollis (IST). We examined nine patients and 13 healthy subjects. The mean values (+/- SD) of peak area ratios were: IST: N-acetyl-aspartate (NAA)/choline-containing compounds (Cho) 1.79 +/- 0.39, NAA/creatine and phosphocreatine compounds (Cr) 1.61 +/- 0.38, Cho/Cr 0.91 +/- 0.19; controls: NAA/Cho 2.07 +/- 0.35, NAA/ Cr 1.82 +/- 0.31, Cho/Cr 0.89 +/- 0.12. Statistical analysis showed that NAA/Cho and NAA/Cr were significantly lower in patients than in controls (P = 0.0304 and 0.0431, respectively). These results indicate a reduction in NAA, and suggest striatal involvement in the pathogenesis IST.