Metabolic abnormality in the cerebellum in patients with essential tremor: A proton magnetic resonance spectroscopic imaging study

The pathological basis for essential tremor (ET) is unknown. We used proton magnetic resonance spectroscopic imaging (¹H MRSI) in 16 ET patients and 11 controls to measure levels of intracellular metabolites, including N-acetyl-L-aspartate (NAA) and total choline, relative to total creatine (tCR), in several brain regions (cerebellum, thalamus, basal ganglia). Multislice ¹H MRSI data were acquired on a 1.5 T GE Signa Scanner by prescribing four 15-mm axial-oblique slices. The mean (standard deviation) cerebellar cortical NAA/tCR was reduced in cases compared to controls (1.53 [0.36] versus 1.91 [0.49], P=0.03). There was an inverse association between cerebellar cortical NAA/tCR and dominant arm tremor severity (r=-0.59, P=0.02). The reduction in cerebellar cortical NAA/tCR indicates that there is neuronal damage or loss in ET, suggesting that ET may be a neurodegenerative disease.