Cerebral activation patterns in patients with writer's cramp: a functional magnetic resonance imaging study

Abstract

Functional MRI (fMRI), visualizing changes in cerebral blood oxygenation, has to date not been performed either in patients with writer's cramp or in healthy subjects during writing. We compared the cerebral and cerebellar activation pattern of 12 patients with writer's cramp during writing with a group of 10 healthy subjects performing the same tasks over 30-s periods of rest or writing. Sixty echo planar imaging multislice datasets were analysed using SPM96 software. Data were analysed for each subject individually and groupwise for patients vs. controls. Healthy subjects showed a significant activation of the ipsilateral dentate nucleus, contralateral cerebellar hemisphere, contralateral primary sensorimotor cortex, and contralateral precentral gyrus during writing. Patients with writer's cramp showed significantly greater activation of the ipsilateral cerebellar hemisphere than controls. Also the activation in the primary sensorimotor cortex extended further caudally and anteriorly towards the premotor association area. Activation was observed in the thalamus during writing only among the patients. Our results indicate an increased basal ganglia output via the thalamus to the motor and premotor cortical areas in dystonia patients and support the notion of disinhibition of the motor cortex leading to cocontractions and dystonic postures.

Cortical Plasticity and Its Implications for Focal Hand Dystonia

“…An fMRI study of patients with writer's cramp during writing demonstrated more significant activation of contralateral thalamus, ipsilateral cerebellar hemisphere, and in particular contralateral primary sensorimotor cortex extending to the premotor association area, in comparison with healthy subjects. This finding supports a hypothesis of extensive motor cortex activation via the thalamus in writer's cramp patients 25 . Another fMRI study demonstrated overlapping and even inversion of particular finger representation in the S1 area of task-specific hand dystonia patients 26 .…”

A Patients with Hemidystonia and Blepharospasm Following Traumatic Injury

“…Other studies also showed cerebral glucose hypermetabolism in the striatum and thalamus of patients with dystonia [18,19]. Moreover, there are several previous reports that activation in the somatosensory cortex was regarded during movement task in dystonic diseases [20,21]. It is surmised that cerebral glucose hypermetabolism in the thalamus, putamen, and PSA, was reflecting the existence of dystonic diseases in the present case.…”

Low-Frequency Oscillations in the Cerebellar Cortex of the Tottering Mouse

“…However, there is increasing evidence for the involvement of the cerebellum in the generation of dystonic movements (Jinnah and Hess 2006;Raike et al 2005). Some dystonia patients have cerebellar structural abnormalities and hypermetabolic signals (Delmaire et al 2007;LeDoux and Brady 2003;Odergren et al 1998;Preibisch et al 2001). In animal models, both the leaner mouse (a Cacna1a mutant) and the Ca v 2.1 null mutant exhibit dystonic movements (Fletcher et al 2001;Green and Sidman 1962).…”