title: Posturographic analysis of balance control in patients with essential tremor.
abstract: Essential tremor (ET) is a common movement disorder causing an important functional disability. ET is generally regarded as a monosymptomatic disorder, but additional signs may be present. We analyzed postural sway in 19 patients with classic ET and in 19 sex- and age-matched normal controls (NC) to uncover possible abnormalities of balance control. Static posturography was performed with eyes open (EO) and closed during quiet stance and during performance of mental calculation or motor sequence of thumb opposition to the other fingers. No significant differences of center of foot pressure (COP) parameters were observed between patients and controls during quiet standing. Visual deprivation induced a similar worsening of postural sway in both groups. Concomitant performance of a cognitive or motor task did not affect COP area, whereas COP path was significantly modified by the cognitive task in both groups. In all EO conditions, the COP path was significantly lower in NC than in ET, but such offset was related only to the group of ET patients with head tremor. This study demonstrates that balance control is only minimally affected in ET, although patients with head involvement and longer disease duration tend to present a reduced postural stability. The "dual-task effect" is less important in ET than in Parkinson's disease patients.
authors.affiliation: Department of Experimental Medicine, Section of Human Physiology, University of Genoa, Genoa, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Bove
authors.forename: Lucio
authors.initials: L
authors.lastname: Marinelli
authors.forename: Laura
authors.initials: L
authors.lastname: Avanzino
authors.forename: Roberta
authors.initials: R
authors.lastname: Marchese
authors.forename: Giovanni
authors.initials: G
authors.lastname: Abbruzzese
mesh_terms: D000328:Adult; D000368:Aged; D001288:Attention / Q000502:physiology; D004185:Disability Evaluation; D020329:Essential Tremor / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009460:Neurologic Examination; D004856:Postural Balance / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D016474:Weight-Bearing / Q000502:physiology