Idiopathic Downbeat Nystagmus Exacerbated with Positional Maneuvers

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This is a 45-yo-woman with vertical oscillopsia for 6+ months, found to have downbeat nystagmus on examination. She mainly complained of dizziness and oscillopsia when laying down. She was found to have a significant exacerbation in her baseline downbeat nystagmus with straight head hanging, and in right and left Dix-Hallpike. Although positional downbeat nystagmus (pDBN) can be seen with the uncommon anterior canal variant of BPPV, usually it is seen with disorders of the cerebellum or cervicomedullary junction. When pDBN is seen in a patient with parkinsonism, multiple system atrophy should be a consideration. In this patient, the downbeat was in isolation, there was no cerebellar ataxia, and extensive evaluation was unrevealing. Number of Figures and legend for each: 0 Number of Videos and legend for each: 1, Patient with downbeat nystagmus, most prominent with positional maneuvers. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This patient mainly complained of dizziness and vertical oscillopsia when assuming a supine position. She was found to have a significant exacerbation in her (very mild) baseline downbeat nystagmus with straight head hanging, and in right and left Dix-Hallpike. Although positional downbeat nystagmus (pDBN) can be seen with the uncommon anterior canal variant of BPPV, usually it is seen with disorders of the cerebellum or cervicomedullary junction. When pDBN is seen in a patient with parkinsonism, multiple system atrophy should be a consideration. In this patient, the downbeat was in isolation, there was no cerebellar ataxia, and extensive evaluation was unrevealing. She did well with 4-aminopyridine and there was no progression over at least 2 years. https://collections.lib.utah.edu/ark:/87278/s66t3w9k