title: Bruns bidirectional nystagmus in cerebellopontine angle tumours.
abstract: Bruns nystagmus is an uncommon, bidirectional optokinetic disturbance associated with advanced cerebellopontine angle tumours. In a retrospective analysis of 115 such tumours, Bruns nystagmus was observed in 18 patients (16%). All tumours in this group were 3 cm or greater in diameter. Fourth ventricle displacement as assessed by computerized cranial tomography was present in all cases where the fourth ventricle was visualized (89%). Seven of 15 cases (47%) had significant contralateral N5 delay on brainstem auditory evoked potential testing, 5 (33%) were normal and 3 (20%) gave no consistent result. It was concluded that Bruns nystagmus occurs in large tumours associated with significant brainstem distortion. The neurophysiological abnormalities demonstrated by brainstem audiometry appear to be a less sensitive measure of brainstem compression than neuro-anatomical assessment using CT.
authors.affiliation: Addenbrooke's Hospital, Cambridge.
authors.forename: G R
authors.initials: GR
authors.lastname: Croxson
authors.forename: D A
authors.initials: DA
authors.lastname: Moffat
authors.forename: D
authors.initials: D
authors.lastname: Baguley
mesh_terms: D001933:Brain Stem / Q000503:physiopathology; D002528:Cerebellar Neoplasms / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D002530:Cerebellopontine Angle / Q000473:pathology / Q000503:physiopathology; D002551:Cerebral Ventricle Neoplasms / Q000556:secondary; D005072:Evoked Potentials, Auditory; D006801:Humans; D009760:Nystagmus, Physiologic; D012189:Retrospective Studies