Table 2. Mean baseline scores and annual slopes of cognitive assessments during the follow-up in the whole cohort.

Cognitive assessment	Published reference range	Score at baseline N = 156	Annual slope ± SE N = 146	p-value
Stroop word reading [10]	≥ 88	61.1 ± 25.3	-4.1 ± 0.3	p<0.0001
Stroop color naming [10]	≥ 65	44.5 ± 20.0	-2.9 ± 0.2	p<0.0001
Stroop interference [10]	≥ 35	23.4 ± 13.9	-1.5 ± 0.2	p<0.0001
SDMT [11]	≥ 37	23.4 ± 15.5	-1.8 ± 0.2	p<0.0001
Verbal fluency test [12]	≥ 56	34.9 ± 22.6	-2.2 ± 0.3	p<0.0001

SDMT: Symbol Digit Modalities Test. Annual slopes are assessed using the mixed-effect linear model and adjusted for age, age at onset, CAG (cytosine-adenine-guanine) and level of education. Results are presented in means ± standard deviation. p-values of the comparison of the mean slopes to 0.