title: A 3-year cohort study of the natural history of spinocerebellar ataxia type 6 in Japan.
abstract: BACKGROUND
  Only a few prospective studies have determined which clinical symptoms and factors are associated with the disease severity of spinocerebellar ataxia type 6 (SCA6). A multicenter longitudinal cohort study was conducted to clarify both the natural history of SCA6 in Japan and the factors influencing disease progression.
  
  
  METHODS
  Patients were consecutively recruited between 2007 and 2008. Scores from the Scale for the Assessment and Rating of Ataxia (SARA) and Barthel Index (BI) were collected prospectively each year. Additionally, data from the Japan intractable diseases research (IDR) registry were collected both retrospectively, from 2003 to 2006, and prospectively, from 2007 to 2010. As a result, we were able to collect 3 years of retrospective data and 4 years of prospective data during the course of 3 yearly visits.
  
  
  RESULTS
  Forty-six patients were registered. The follow-up rate of the third year was 93%. The SARA scores worsened significantly each year. Over 3 years, the decline of the SARA scores was 1.33 ± 1.40 points/year. The results of multivariate analysis of the decline of the SARA score were not significant. The IDR scores correlated well with the SARA and BI scores. Kaplan-Meier curves of 7 years of data from the IDR registry illustrated the correlation between the ability to walk and the time course of the disease.
  
  
  CONCLUSIONS
  Information regarding the progression of ataxia and the decline in the activities of daily living (ADL) in patients with SCA6 was obtained by a 3-year cohort study and a 7-year IDR study. The decline of the SARA score of patients with SCA6 was 1.33 ± 1.40 points/year. The results elucidate the natural history of SCA6, factors influencing disease severity, and utility of data from the IDR registry of Japan.
authors: Kenichi
authors: K
authors: Yasui
authors: Ichiro
authors: I
authors: Yabe
authors: Kunihiro
authors: K
authors: Yoshida
authors: Kazuaki
authors: K
authors: Kanai
authors: Kimihito
authors: K
authors: Arai
authors: Mizuki
authors: M
authors: Ito
authors: Osamu
authors: O
authors: Onodera
authors: Shigeru
authors: S
authors: Koyano
authors: Eiji
authors: E
authors: Isozaki
authors: Setsu
authors: S
authors: Sawai
authors: Yoshiki
authors: Y
authors: Adachi
authors: Hidenao
authors: H
authors: Sasaki
authors: Satoshi
authors: S
authors: Kuwabara
authors: Takamichi
authors: T
authors: Hattori
authors: Gen
authors: G
authors: Sobue
authors: Hidehiro
authors: H
authors: Mizusawa
authors: Shoji
authors: S
authors: Tsuji
authors: Masatoyo
authors: M
authors: Nishizawa
authors: Kenji
authors: K
authors: Nakashima
mesh_terms: D015331:Cohort Studies; D006801:Humans; D007564:Japan; D011446:Prospective Studies; D012042:Registries; D020754:Spinocerebellar Ataxias / Q000503:physiopathology*