Vestibular evaluation in autosomal dominant cerebellar ataxia with prevalence in the south of Brazil

Introduction Autosomal dominant cerebellar ataxias (ADCAs) represent a heterogeneous group of neurodegenerative disorders primarily affecting the cerebellum and its afferent and efferent connections, particularly brainstem, and spinal cord. Classical clinical findings of spinocerebellar ataxias (SCAs) are progressive gait and limb cerebellar ataxia, associated with nystagmus, dysarthria, and ophthalmoparesis. The fundamental element for vestibular analysis is nystagmus, which is a series of ocular movements with fast and slow components in opposite directions, and which occur alternately. The tests which comprise the vestibular exam allow an evaluation of the relationship between balance and posterior vestibular labyrinth function, the vestibular branches of the VIII cranial nerve, the vestibular nuclei in the floor of the IV ventricle, the vestibular pathways and especially, the vestibulo-oculomotor, vestibulocerebellar, vestibulospinal and vestibuloproprioceptive-cervical inter-connections. To describe the alterations observed in electronystagmography (ENG) of patients with spinocerebellar ataxia (SCA) types 2 and 3. Material and method Twenty-two patients were studied and the following procedures were carried out: anamnesis, otorhinolaryngological and vestibular evaluations. Results The clinical findings in the entire group of patients were: gait disturbances (93.7%), dysarthria (43.7%), headache (43.7%), dizziness (37.5%) and dysphagia (37.5%). In the vestibular exam, the rotatory (62.5%) and caloric (75%) tests were among those which presented the largest indexes of abnormalities; the presence of alterations in the exams was 87.5%, with a predominance of central vestibular disorders in 68.7% of the exams. Conclusion Vestibular exams could be an auxiliary tool to investigate SCAs, besides a precise clinical approach and, particularly, molecular genetic tests.