title: Lower limb joints kinematics in essential tremor and the effect of thalamic stimulation.
abstract: Following the hypothesis that thalamic deep brain stimulation improves ataxia in patients with essential tremor by modulating the cerebello-thalamo-cortical pathway, we examined the joint kinematics of lower limbs during uninterrupted gait in eleven patients who have been treated with bilateral thalamic stimulation for 24.7±20.3 months. Patients were assessed under routine chronic stimulation, supra-therapeutic amplitude, and off stimulation by means of an infrared movement analysis system while walking on a treadmill. Chronic thalamic DBS normalized the highly variable excursion throughout the gait cycle that characterized the subgroup of patients with longest disease duration. Supratherapeutic thalamic DBS amplitude did not reproduce such improvements while, more importantly, it induced ataxic changes of joint excursion. The normalization of kinematic abnormalities argues against the hypothesis of a cerebellar neurodegeneration in ET. Moreover, these results suggest that the beneficial effect of thalamic DBS on ataxic symptoms is limited to a narrow therapeutic window.
authors.affiliation: Istituto di Neurologia, Università Cattolica del Sacro Cuore, Roma, Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Fasano
authors.forename: Jan
authors.initials: J
authors.lastname: Herzog
authors.forename: Jan
authors.initials: J
authors.lastname: Raethjen
authors.forename: Franziska E M
authors.initials: FE
authors.lastname: Rose
authors.forename: Jens
authors.initials: J
authors.lastname: Volkmann
authors.forename: Daniela
authors.initials: D
authors.lastname: Falk
authors.forename: Günther
authors.initials: G
authors.lastname: Deuschl
mesh_terms: D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D046690:Deep Brain Stimulation; D020329:Essential Tremor / Q000150:complications* / Q000628:therapy; D005260:Female; D020234:Gait Ataxia / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D013788:Thalamus