Postural Tremor and Ataxia Progression in Spinocerebellar Ataxias

Shi-Rui Gan; Jie Wang; Karla P. Figueroa; Stefan M. Pulst; Darya Tomishon; Danielle Lee; Susan Perlman; George Wilmot; Christopher M. Gomez; Jeremy Schmahmann; Henry Paulson; Vikram G. Shakkottai; Sarah H. Ying; Theresa Zesiewicz; Khalaf Bushara; Michael D. Geschwind; Guangbin Xia; S. H. Subramony; Tetsuo Ashizawa; Sheng-Han Kuo

doi:10.5334/tohm.346

Figures & Tables

Table 1

Baseline Neurological Features of 315 Participants in the Different Subtypes of SCA

Variables, n (%)	SCA1, n = 52	SCA2, n = 69	SCA3, n = 129	SCA6, n = 65	p¹
Postural tremor					0.006
No	49 (94.2)	50 (72.5)	113 (87.6)	54 (83.1)
Yes	3 (5.8)	19 (27.5)	16 (12.4)	11 (16.9)

Abbreviations: SCA = Spinocerebellar Ataxias.

The value in bold represents statistical significance.

1 Chi-square test.

Table 2

Baseline Features of 315 Participants Grouped by Neurological Features in the Different Subtypes of SCA

	SCA1, n = 52		p	SCA2, n = 69		p	SCA3, n = 129		p	SCA 6, N = 65		p
	Postural Tremor	No Postural Tremor	p	Postural Tremor	No postural Tremor	p	Postural Tremor	No Postural Tremor	p	Postural Tremor	No postural tremor	p
N (%)	3 (5.8)	49 (94.2)		19 (27.5)	50 (72.5)		16 (12.4)	113 (87.6)		11 (16.9)	54 (83.1)
Age of onset (years)	24.00 ± 7.94	41.18 ± 11.35	0.013¹	37.56 ± 14.38	36.32 ± 11.04	0.709¹	33.44 ± 10.26	39.61 ± 11.90	0.051¹	45.82 ± 11.81	53.44 ± 19.84	0.027¹
Gender, M : W	3 : 0	25 : 24	0.291²	13 : 6	27 : 23	0.278²	7 : 9	60 : 53	0.484²	2 : 9	34 : 20	0.017²
CAG repeat (numbers)	50.00 ± 7.81	45.83 ± 4.19	0.118¹	39.21 ± 4.91Median = 40.00	39.67 ± 2.91Median = 39.00	0.576³	73.67 ± 3.12	70.42 ± 3.96	0.003¹	22.55 ± 1.51Median = 22.00	22.33 ± 0.81Median = 22.00	0.902³
Disease duration (years)	5.33 ± 2.89	10.43 ± 7.24	0.234¹	15.61 ± 7.64	14.40 ± 9.02	0.614¹	15.31 ± 7.31	12.02 ± 7.47	0.100¹	19.09 ± 10.92	12.46 ± 10.30	0.059¹
Baseline SARA score	16.42 ± 11.19	14.23 ± 8.22	0.663¹	19.34 ± 7.80	15.99 ± 7.30	0.099¹	17.66 ± 7.44	14.72 ± 9.09	0.219¹	17.70 ± 4.79	13.75 ± 7.65	0.105¹

Abbreviations: SCA = Spinocerebellar Ataxia; SARA = Scale for Assessment and Rating of Ataxia.

Values represent mean ± standard deviation or number, and for variables with non-normal distribution, the median is reported as well.

The value in bold represents statistical significance.

1 Two independent samples t-test.

2 Chi-square test.

3 Two independent samples Mann–Whitney U test.

Table 3

Longitudinal SARA Scores of the Different Neurological Symptoms in the GEE Model

Variables	Regression Coefficients of SARA Score¹
Variables	SCA1	SCA2	SCA3	SCA6
Age of first visit (years)	0.62 (<0.001)	0.41 (<0.001)	0.58 (<0.001)	0.37 (<0.001)
Gender²	4.61 (0.013)	–0.98	–0.78	–1.80
CAG repeat (numbers)	1.57 (<0.001)	1.79 (<0.001)	1.51 (<0.001)	2.06 (<0.001)
Postural tremor³	–3.66	2.25	1.44	6.04 (<0.001)
Visit time	1.01 (<0.001)	0.20	0.38 (0.025)	1.58 (<0.001)
Postural tremor × visit time	–0.91 (<0.001)	1.54 (0.034)	–0.22	–1.28 (0.025)

Abbreviations: SARA = Scale for Assessment and Rating of Ataxia; GEE = Generalized Estimating Equation; SCA = Spinocerebellar Ataxia.

1 All regression coefficients and p-values were calculated in the GEE model, adjusting for age of first visit, gender, CAG repeat, neurological symptom, and neurological symptom × visit time.

2 Men = 0, Women = 1

3 No postural tremor = 0; postural tremor = 1.

Table 4

Logistic Regression Analyses for Influencing Factors of Postural Tremor in the Different Subtypes of SCA

Variables	Dependent Variable: Postural Tremor
	SCA1			SCA2			SCA3			SCA6
	β	OR	p	β	OR	p	β	OR	p	β	OR	p
Age of first visit (years)	–1.51	0.22	0.999	0.12	1.13	0.139	0.04	1.04	0.450	–0.02	0.99	0.697
Gender¹	–28.29	0.00	0.999	–2.28	0.10	0.077	0.40	1.49	0.632	2.09	8.07	0.032
ATXN1 (SCA1) repeat numbers	–0.54	0.58	1.000	–1.53	0.22	0.037	0.14	1.16	0.518	0.34	1.41	0.231
ATXN2 (SCA2) repeat numbers	–13.02	0.00	0.999	0.45	1.57	0.205	–0.07	0.93	0.853	–0.53	0.59	0.454
ATXN3 (SCA3) repeat numbers	–0.26	0.78	1.000	0.57	1.76	0.018	0.23	1.26	0.177	–0.09	0.92	0.524
CACNA1A (SCA6) repeat numbers	3.59	36.07	1.000	1.80	6.07	0.063	0.03	1.03	0.944	0.66	1.93	0.141
ATXN7 (SCA7) repeat numbers	–0.06	0.94	1.000	–0.71	0.49	0.265	0.11	1.12	0.723	0.08	1.09	0.850
ATXN10 (SCA10) repeat numbers	–1.71	0.18	1.000	–0.53	0.59	0.144	0.00	1.00	0.996	–0.25	0.78	0.370
PPP2R2B (SCA12) repeat numbers	–9.07	0.00	0.998	0.21	1.24	0.343	–0.40	0.67	0.032	0.05	1.05	0.740
TBP (SCA17) repeat numbers	–14.51	0.00	0.999	0.09	1.09	0.841	0.63	1.87	0.041	–0.44	0.64	0.353
FXN (FA) repeat numbers	0.26	1.29	1.000	0.06	1.06	0.617	0.04	1.04	0.562	–0.08	0.93	0.417

The values in bold represent statistical significance.

1 Men = 0, Women = 1.