title: Vestibular Performance During High-Acceleration Stimuli Correlates with Clinical Decline in SCA6.
abstract: In spinocerebellar ataxia type 6 (SCA6), the vestibular dysfunction and its correlation with other clinical parameters require further exploration. We determined vestibular responses over a broad range of stimulus acceleration in 11 patients with SCA6 (six men, age range=33-72 years, mean age±SD=59±12 years) using bithermal caloric irrigations, rotary chair, and head impulse tests. Correlations were also pursued among disability scores, as measured using the International Cooperative Ataxia Rating Scale, disease duration, age at onset, cytosine-adenine-guanine (CAG) repeat length, and the gain of the vestibulo-ocular reflex (VOR). In response to relatively low-acceleration, low-frequency rotational and bithermal caloric stimuli, the VOR gains were normal or increased regardless of the severity of disease. On the other hand, with relatively high-acceleration, high-frequency head impulses, there was a relative increase in gain in the mildly affected patients and a decrease in gain in the more severely affected patients and gains were negatively correlated with the severity of disease (Spearman correlation, R=-0.927, p<0.001). Selective decrease of the vestibular responses during high-acceleration, high-frequency stimuli may be ascribed to degeneration of either the flocculus or vestibular nuclei. The performance of the VOR during high-acceleration, high-frequency head impulses may be a quantitative indicator of clinical decline in SCA6.
authors.affiliation: Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea.
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Huh
authors.forename: Ji-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Hyo-Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Beom Seok
authors.initials: BS
authors.lastname: Jeon
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Jin Whan
authors.initials: JW
authors.lastname: Cho
authors.forename: David S
authors.initials: DS
authors.lastname: Zee
mesh_terms: D000054:Acceleration; D000328:Adult; D000368:Aged; D005260:Female; D064087:Head Impulse Test / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D012027:Reflex, Vestibulo-Ocular; D012399:Rotation; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000503:physiopathology*; D014724:Vestibular Function Tests / Q000379:methods; D014726:Vestibular Nuclei / Q000503:physiopathology