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Table 4 Time course of disease progression based on the SARA, BI, IDR-ICARS and IDR-BI scores

From: A 3-year cohort study of the natural history of spinocerebellar ataxia type 6 in Japan

Follow-up year −4 −3 −2 −1 Registration 1 2 3 Total
N (follow-up rate%) 29 35 38 40 46(100) 44(96) 44(96) 43(93) 177*
Death, n      0 1 0 1 2
Withdrawal, n      0 1 0 0 1
SARA score, points      15.9 ± 7.1 16.8 ± 6.9a 18.2 ± 7.2a 19.1 ± 6.9a 17.5 ± 7.1
ΔSARA, points      0 1.35 ± 1.70 2.78 ± 2.78 3.73 ± 3.17 n/a
ΔSARA/year, points/y      0 1.35 ± 1.70 1.39 ± 1.39 1.24 ± 1.06 1.33 ± 1.40
BI score, points      77.4 ± 22.4 77.4 ± 22.3b 73.8 ± 23.7b 75.0 ± 23.2 75.9 ± 22.8
IDR-ICARS score, points 13.9 ± 5.9 13.7 ± 5.9 14.1 ± 6.0c 14.6 ± 5.7 14.8 ± 6.0 15.0 ± 5.4b 16.0 ± 5.7b 16.2 ± 5.6 14.9 ± 5.8
ΔIDR-ICARS, points −2.28 ± 3.59 −2.06 ± 3.27 −1.29 ± 2.98 −0.50 ± 2.32 0 0.59 ± 1.65 1.59 ± 2.34 1.77 ± 2.79 n/a
ΔIDR-ICARS/year, points/y −0.57 ± 0.90 −0.69 ± 1.09 −0.64 ± 1.49 −0.50 ± 2.32 0 0.59 ± 1.65 0.80 ± 1.17 0.59 ± 0.93 0.63 ± 1.45d
IDR-BI score, points 37.1 ± 14.0 38.6 ± 14.2 38.4 ± 13.8c 37.4 ± 14.1 36.7 ± 15.1 37.6 ± 15.0 34.9 ± 14.8b 35.8 ± 14.9 36.3 ± 14.9
  1. Where applicable, the values are given as the mean ± standard deviation.
  2. Comparisons of the IDR-ICARS, IDR-BI, SARA, and BI scores of each year were made by using the Friedman test followed by the Wilcoxon signed rank test as a post hoc test.
  3. Abbreviations: BI = Barthel Index; ICARS = International Cooperative Ataxia Rating Scale; IDR = Intractable Diseases Research; n/a = not applicable; SARA = Scale for the Assessment and Rating of Ataxia.
  4. IDR-BI = total points of 6 items from the BI assessed by the IDR registry.
  5. IDR-ICARS = total points of 5 items from the ICARS assessed by the IDR registry.
  6. ΔIDR-ICARS and ΔSARA = differences between the scores obtained at the follow-up evaluations and those obtained at registration for the IDR-ICARS and SARA, respectively.
  7. aP < .001, versus the previous year for the prospective study.
  8. bP < .05 versus the previous year for the prospective study.
  9. cP < .05 versus the next year for the retrospective study.
  10. dTotal of the IDR-ICARS/year calculated with the absolute value of each ΔIDR-ICARS/year excluding that of the registration year.
  11. *Total number of evaluations conducted during the prospective arm of the study.