title: Disorders of balance and gait in essential tremor are associated with midline tremor and age.
abstract: Disorders of balance and gait have been observed in patients with essential tremor (ET), but their association with tremor severity remains unclear. This study aimed to evaluate postural instability and gait changes in ET patients and to investigate their relationship to tremor characteristics with regard to cerebellar dysfunction as a possible common pathogenetic mechanism in ET. Thirty ET patients (8F, mean (SD) age 55.8 (17.8), range 19-81 years) and 25 normal controls (7F, 53.0 (17.7), 19-81) were tested with the scales of Activities-specific Balance Confidence (ABC), Fullerton Advanced Balance (FAB), and International Cooperative Ataxia Rating Scale (ICARS). Posturography and gait were assessed using a Footscan® system. Tremor was evaluated by the Fahn-Tolosa-Marin Tremor Rating Scale (TRS) and accelerometry in five upper limb positions. A mean (SD) TRS sum score of 27.0 (13.2) corresponded to mild to moderate tremor severity in most patients. In comparison with controls, ET subjects exhibited lower tandem gait velocity (0.21 vs. 0.26 m/s, P = 0.028), more missteps (0.57 vs. 0.12, P = 0.039), and increased postural sway in tandem stance (sway area 301.1 vs. 202.9 mm(2), P = 0.045). In normal gait, step width increased with the midline tremor subscore of TRS (Pearson r = 0.60, P = 0.046). Moreover, significant correlations were found between age and quantitative measures of normal and tandem gait in ET patients but not in controls. ABC, FAB, and ICARS scores did not significantly differ between patients and controls. In conclusion, gait and balance alterations in ET patients occur even without subjective complaints. Their relationship with midline tremor and dependence on age suggest a connection with cerebellar dysfunction.
authors.affiliation: Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague, Charles University in Prague, Kateřinská 30, Prague, 128 21, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Hoskovcová
authors.forename: Olga
authors.initials: O
authors.lastname: Ulmanová
authors.forename: Otakar
authors.initials: O
authors.lastname: Sprdlík
authors.forename: Tomáš
authors.initials: T
authors.lastname: Sieger
authors.forename: Jana
authors.initials: J
authors.lastname: Nováková
authors.forename: Robert
authors.initials: R
authors.lastname: Jech
authors.forename: Evžen
authors.initials: E
authors.lastname: Růžička
mesh_terms: D061725:Accelerometry; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002526:Cerebellar Diseases / Q000175:diagnosis / Q000503:physiopathology*; D020329:Essential Tremor / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000175:diagnosis / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D012720:Severity of Illness Index; D055815:Young Adult