Cerebellar ataxia with auditory neuropathy and vestibular are flexia. A new variant of CANVAS syndrome?

Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a rare neurological syndrome of unknown etiology. The main clinical features include bilateral vestibulopathy, cerebellar ataxia and sensory neuropathy with normal auditory function. An abnormal visually enhanced vestibulo-ocular reflex is the hallmark of the disease. We present a case of 35-year-old male patient who has demonstrated bilateral rapidly progressive hearing loss that eventually ended in total hearing loss in both ears within few months. On audiologic evaluation the type of hearing loss was due to auditory neuropathy (abnormal auditory pathway with intact cochlear function). On examination ataxia of gait, normal knee and ankle reflexes, gaze-evoked downbeat nystagmus and abnormal visually enhanced vestibulo-ocular reflex were found. Brain magnetic resonance imaging revealed no abnormality. Vestibular function testing no response to ice caloric stimulation. Nerve conduction studies was completely normal. The course of illness was progressive with ataxic gait and unsteadiness as the most disabling symptoms.