Progressive Apraxia of Speech as a Manifestation of Spinocerebellar Ataxia 2: Case Report

To describe a case of spinocerebellar ataxia presenting with progressive apraxia of speech (AOS).

A 54-year-old man with progressive speech changes was seen clinically and referred to our observational research program on degenerative speech and language disorders. He underwent detailed speech-language and neurologic assessments and multimodal neuroimaging studies. Three board-certified speech-language pathologists, blinded to other study data, reached a consensus speech diagnosis.

The patient reported 2 years of progressive speech changes against a background of mild imbalance. Speech alternating and sequential motion rates were regular but moderately slow. He segmented syllables, most prominently during repetition of multisyllabic words, and had decreased prosodic variation in connected speech. He was diagnosed with prosodic-predominant primary progressive AOS. He had mild extremity ataxia and difficulty with tandem gait on neurologic examination. MRI showed marked pontine-cerebellar atrophy. FDG-PET showed premotor area and posterior fossa hypometabolism. Genetic testing revealed cytosine-adenine-guanine repeat expansion in the ATXN2 gene, consistent with spinocerebellar ataxia type 2 (SCA2).

SCA2 is an autosomal dominant, degenerative disease characterized by cerebellar ataxia, including ataxic dysarthria. Our case demonstrates that SCA2 can manifest with progressive AOS. Neuroimaging supported involvement of areas classically associated with AOS.