title: Gaze-evoked nystagmus induced by alcohol intoxication.
abstract: The cerebellum is the core structure controlling gaze stability. Chronic cerebellar diseases and acute alcohol intoxication affect cerebellar function, inducing, among others, gaze instability as gaze-evoked nystagmus. Gaze-evoked nystagmus is characterized by increased centripetal eye-drift. It is used as an important diagnostic sign for patients with cerebellar degeneration and to assess the 'driving while intoxicated' condition. We quantified the effect of alcohol on gaze-holding using an approach allowing, for the first time, the comparison of deficits induced by alcohol intoxication and cerebellar degeneration. Our results showed that alcohol intoxication induces a two-fold increase of centripetal eye-drift. We establish analysis techniques for using controlled alcohol intake as a model to support the study of cerebellar deficits. The observed similarity between the effect of alcohol and the clinical signs observed in cerebellar patients suggests a possible pathomechanism for gaze-holding deficits.
  
  
  
  Gaze-evoked nystagmus (GEN) is an ocular-motor finding commonly observed in cerebellar disease, characterized by increased centripetal eye-drift with centrifugal correcting saccades at eccentric gaze. With cerebellar degeneration being a rare and clinically heterogeneous disease, data from patients are limited. We hypothesized that a transient inhibition of cerebellar function by defined amounts of alcohol may provide a suitable model to study gaze-holding deficits in cerebellar disease. We recorded gaze-holding at varying horizontal eye positions in 15 healthy participants before and 30 min after alcohol intake required to reach 0.6‰ blood alcohol content (BAC). Changes in ocular-motor behaviour were quantified measuring eye-drift velocity as a continuous function of gaze eccentricity over a large range (±40 deg) of horizontal gaze angles and characterized using a two-parameter tangent model. The effect of alcohol on gaze stability was assessed analysing: (1) overall effects on the gaze-holding system, (2) specific effects on each eye and (3) differences between gaze angles in the temporal and nasal hemifields. For all subjects, alcohol consumption induced gaze instability, causing a two-fold increase [2.21 (0.55), median (median absolute deviation); P = 0.002] of eye-drift velocity at all eccentricities. Results were confirmed analysing each eye and hemifield independently. The alcohol-induced transient global deficit in gaze-holding matched the pattern previously described in patients with late-onset cerebellar degeneration. Controlled intake of alcohol seems a suitable disease model to study cerebellar GEN. With alcohol resulting in global cerebellar hypofunction, we hypothesize that patients matching the gaze-holding behaviour observed here suffered from diffuse deficits in the gaze-holding system as well.
authors.affiliation: Department of Computer, Electrical and Biomedical Engineering, University of Pavia, Pavia, Italy.|Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Fausto
authors.identifier: 0000-0002-6166-7461
authors.initials: F
authors.lastname: Romano
authors.affiliation: Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Tarnutzer
authors.affiliation: Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Straumann
authors.affiliation: Department of Computer, Electrical and Biomedical Engineering, University of Pavia, Pavia, Italy.
authors.forename: Stefano
authors.identifier: 0000-0001-5932-186X
authors.initials: S
authors.lastname: Ramat
authors.affiliation: Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bertolini
mesh_terms: D000328:Adult; D000435:Alcoholic Intoxication / Q000503:physiopathology*; D002531:Cerebellum / Q000503:physiopathology; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D010775:Photic Stimulation
keywords: alcohol; cerebellum; gaze-evoked nystagmus; gaze-holding; model for cerebellar disease