Abnormal Visually-enhanced Vestibulo-ocular Reflex (vVOR) in Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS)

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This patient complained of chronic (unexplained cough), progressive numbness in the legs and feet, gait instability, and oscillopsia when walking or with head movements. Examination showed excessive square-wave jerks, bilateral horizontal gaze-evoked nystagmus, bilaterally abnormal head impulse testing, saccadic vVOR (seen with slow head turning to the right and left, abnormal due to combination of poor pursuit and bilateral vestibular loss). A clinical diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) was made. An impaired or saccadic vVOR suggests that there is failure of both the pursuit and (usually bilateral) vestibular systems, and CANVAS should be considered, especially when neuropathy and chronic cough are also present. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This patient complained of chronic (unexplained cough), progressive numbness in the legs and feet, gait instability, and oscillopsia when walking or with head movements. Examination showed excessive square-wave jerks, bilateral horizontal gaze-evoked nystagmus, bilaterally abnormal head impulse testing, saccadic vVOR (seen with slow head turning to the right and left, abnormal due to combination of poor pursuit and bilateral vestibular loss). A clinical diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) was made. An impaired or saccadic vVOR suggests that there is failure of both the pursuit and (usually bilateral) vestibular systems, and CANVAS should be considered, especially when neuropathy and chronic cough are also present.