Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, The Johns Hopkins School of Medicine
This is a 60-yo-woman with several years of worsening imbalance, diplopia (hers was actually unrelated to cerebellar pathology [although she did have an esotropia greater at distance that was cerebellar in origin] and due to thyroid eye disease) and blurry vision (due to her spontaneous nystagmus). There was also corectopia OD and she was status post cataract surgery in this eye. Examination demonstrated alternating right-beating and left-beating nystagmus every 90 or so seconds (with a null period in between) consistent with periodic alternating nystagmus (PAN). PAN localizes to the nodulus and uvula, and is occasionally seen with cerebellar degenerations (SCA 6 among others). Baclofen can be helpful for PAN, and therapy was initiated in this particular patient. She also had hypermetric saccades, choppy smooth pursuit and VOR suppression, gaze-evoked nystagmus, as well as perverted nystagmus with head-shaking - i.e., with horizontal head-shaking, vertical nystagmus (downbeating) was apparent). This is another central vestibular/ocular motor sign, and can also be seen with nodulus/uvula pathology - this finding can be seen at the end of the video.
Spencer S. Eccles Health Sciences Library, University of Utah