Objective: To evaluate the prevalence, spectrum, and severity of cognitive impairment in Indian patients with genetically confirmed SCA and corelate with motor severity.

Background: Beyond motor coordination, the cerebellum plays an important role in cognition, manifesting as cerebellar cognitive affective syndrome (CCAS). Cognitive dysfunction in spinocerebellar ataxias (SCAs), prototype of neurodegenerative cerebellar disorder, remains incompletely characterized.

Method: In this prospective cross-sectional study conducted over 12 months, 26 adults (≥18 years) with ≥10 years of formal education were recruited. All underwent structured neurological evaluation and cognitive assessment using Addenbrooke’s Cognitive Examination (ACE-III), Frontal Assessment Battery (FAB), and Neuropsychiatric Inventory (NPI). The Brief Ataxia Rating Scale (BARS) and Cerebellar Cognitive Affective Syndrome (CCAS) scale were also administered to assess cerebellar motor and cognitive dysfunction, respectively (Ref.1,2). The study was approved by the Institutional Ethics Committee.

Results: Twenty-six patients were included. Most were men (69%) with mean age 49 years (SD 9; range 33–70). Mean disease duration was 7 years (±4.4; range 4–20). SCA12 was the most common subtype (58%), followed by SCA2 (15%), SCA3 (11%), SCA46 (7%), SCA17 (4%), and SCA48 (4%).

Motor features included oculomotor abnormalities (100%), ataxia (85%), dysarthria (81%), tremor (77%), parkinsonism (50%), and peripheral neuropathy (11%). Most had mild motor disability on BARS (mean 10 ±5.8; range 5–22).

Cognitive impairment on the CCAS scale was seen in 96%, though only 38% reported symptoms. Deficits involved category switching (89%), phonemic (31%) and semantic fluency (55%), digit span (42%), and cube drawing (43%), indicating executive, language, and visuospatial dysfunction consistent with a cerebellar cognitive–affective pattern. ACE-III showed mild impairment, while FAB and NPI were largely normal. No correlation was found between CCAS and BARS scores.

Conclusion: In our study of Indian patients with SCA, cognitive impairment was highly prevalent, though in majority it was subclinical. The profile of cognitive dysfunction suggested impairment of dorsolateral frontal, language and visuo-spatial networks. The poor co-relation between the cognitive and motor disability suggests that cognitive deficits may occur via networks independent of  motor impairment.

References: 1.Thieme A, Roeske S, Faber J, et al. Validation of a German version of the Cerebellar Cognitive Affective/Schmahmann Syndrome Scale: preliminary version and study. Cerebellum. 2023;22:1–11.

2.Hoche F, Guell X, Vangel MG, Sherman JC, Schmahmann JD. The cerebellar cognitive affective/Schmahmann syndrome scale. Brain. 2018;141(1):248–270.

« Back to 2026 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/cognitive-profile-in-indian-patients-with-spinocerebellar-ataxia-sca-prospective-cross-sectional-study/