Pendular nystagmus in progressive ataxia and palatal tremor

Abstract

Pendular nystagmus (PN) is an involuntary ocular oscillation that can be found in congenital or acquired visual or central nervous system diseases [1, 2]. We describe the case of a patient with PN associated with progressive cerebellar ataxia and palatal tremor (PAPT). The PN has been registered and analyzed with video-oculography. A 55-year-old man complained of a 2-year history of progressive difficulty with running and walking accompanied by unsteadiness. Over this time, he described transient oscillopsia. In retrospect, he reported a long history of difficulty in biking and subtle visual disturbances and tinnitus (but no ear click). There was no relevant family and past medical history. Examination revealed wide-based and unsteady gait, impossible tandem walk and marked dystasia at the single leg stance test (Video 1). The other cerebellar tests were normal (Video 2). Tendon reflexes were brisk at four limbs. The nystagmus was almost invisible at eye (Video 3, part 1), although it could be easily demonstrated by video-oculography (Video 3, part 2), as well as the palatal tremor at the oropharyngeal inspection (Video 3, part 3). The PN had a frequency of about 0.5–1 Hz. It mainly developed on the vertical and the horizontal axis with a secondary rotatory counter-clockwise component (Fig. 1). Best-corrected visual acuity was 20/20. Dynamic visual acuity test was normal. Brain MRI showed mild cerebellar atrophy, more prominent in the lateral part of the hemispheres and signal abnormalities in both inferior olives, which appeared enlarged, and in the decussation of the dentatorubral tracts (Fig. 2). Laboratory tests, including thyroid hormones, antibodies anti-gliadin, -endomysium, transglutaminase, -glutamic acid dehydrogenase, -voltage-gated calcium channel, and -cerebellum were within normal range or negative. Needle biopsy of the quadriceps showed a mild increase in lipid content without morphological and histoenzymatic abnormalities. Genetic tests for POLG1, SCA1, SCA2, SCA6, and FXN (Friedreich ataxia) mutations were negative. Diagnosis of sporadic PAPT can be made in the presence of non-familiar degenerative progressive ataxia and palatal tremor [3]. Ocular oscillations typically coexist in the form of vertical PN [4]. Due to the absence of brainstem morphological abnormalities and of dentate calcifications, adult-onset Alexander’s disease [5, 6] and spinocerebellar ataxia type 20 [7] seem unlikely. Electronic supplementary material The online version of this article (doi:10.1007/s00415-011-6007-z) contains supplementary material, which is available to authorized users.