Hypermetabolism in the ventrolateral thalamus in unilateral Parkinsonian resting tremor: a positron emission tomography study

Tremorogenesis in Parkinson's disease (PD) is assumed to involve a cerebral network including the thalamus. An imaging study was performed on eight PD patients with strictly unilateral resting tremor using fluorodeoxyglucose positron emission tomography coregistered to 3-dimensional magnetic resonan ce imaging. Increased metabolic activity of high statistical significance ( P < 0.001) was found in the anterior ventrolateral nuclear group of the tha lamus located contralateral to the tremor side. The metabolic changes signi ficantly covaried with tremor amplitudes. For the fi rst time, it could be demonstrated that thalamic metabolic changes associated with tremor in PD a re localized in the ventral lateral anterior nucleus (VLa). The results ar e discussed with respect to previous studies on tremor generation. (C) 2001 Published by Elsevier Science Ireland Ltd.