SOD1 and Cognitive impairment: Moreover, previous studies demonstrated that an intermediate-length CAG number of repeats (31–32) of ATXN2 seems to determine a specific disease phenotype characterized by a more common spinal onset, a more rapid clinical progression and spreading of symptoms, a higher risk of developing cognitive impairment, and a 1-year shorter survival compared to ALS ATXN2 patients [17] [18].