Cognition in Trinucleotide Repeat Spinocerebellar Ataxias: A Review

Spinocerebellar ataxias (SCAs) comprise a group of complex and heterogeneous hereditary neurodegenerative disorders characterized by cerebellar ataxia, with ophthalmoplegia, pyramidal and extrapyramidal features, peripheral neuropathy, motor neuron disease, pigmentary retinopathy, epilepsy, and dementia in varying proportions. Cognitive impairment is not frequent in SCAs but is rarely noticed since it gets camouflaged behind the exorbitant ataxic manifestations of the disease. The exact incidence and extent of cognitive impairment in these rare disorders are not known due to the heterogeneity between different SCA types and different modalities of testing employed in different studies. Through our review, we have summarized the cognitive aspects of SCA and can safely conclude that cognitive dysfunction is common in some SCA types when compared to others. Not only is it important to appreciate its presence as a symptom complex in SCA but also is the need to actively search and treat it to improve the patients' quality of life.