Table 2.

Annual worsening rate estimated for this series

Patients		N	Annual worsening index (average ± SD)	95% confidence interval for mean
1 year − baseline	SCA3	19	−1.54 ± 3.0	−2.89	−0.19
	SCA7	6	−2.12 ± 2.1	−3.80	−0.44
	SCA6	1	−3	−3	−3
2 nd year (extension)	SCA3	6	−0.08 ± 1.11	−0.97	0.81
	SCA7	4	0.63 ± 1.93	−1.26	2.52
Control SCA3		139	1.61 ± 0.12	1.59	1.63
Control SCA7		7	1.5 ± 0.9	0.79	2.21
Control SCA6		107	0.35 ± 0.34	0.29	0.41

Comprehensive quantitative account of disease progression was given by Jacobi et al. [26]. N number.