The Cerebellar Cognitive‐Affective Syndrome Scale Reveals Consistent, Early, and Progressive Neuropsychological Deficits in Autosomal‐Recessive Spastic Ataxia of Charlevoix‐Saguenay: A Large International Cross‐Sectional Study

BACKGROUND: Neuropsychological deficits have been observed in patients with cerebellar damage, but never thoroughly investigated in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). OBJECTIVES: The goal is the characterization of presence, severity, and profile of neuropsychological deficits in ARSACS using the cerebellar cognitive-affective syndrome (CCAS) scale. METHODS: Prospective study including a discovery cohort from Saguenay/Canada (n = 31, median [inter-quartile range] age: 57 [54-62] years), and a validation cohort from Tübingen, Germany (n = 17, 35 [21-43] years) with matched controls (n = 19). RESULTS: All ARSACS patients failed in multiple CCAS-related subtests and exceeded cutoffs for "definite CCAS." Even the younger validation cohort failed more subtests than controls (5 [3-7] vs. 1 [1-2], P < 0.001) and had lower CCAS total scores (81 [67-86] vs. 101 [91-106], P < 0.001). Total scores worsened in the older discovery cohort (40 [25-52], P < 0.001) and correlated with age/disease duration (ρ = -0.575, P < 0.001) and ataxia severity (Scale for the Assessment and Rating of Ataxia: ρ = -0.527, P = 0.003). CONCLUSIONS: Neuropsychological deficits consistent with CCAS are consistent in ARSACS, present early, and progress in the disease course. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.