title: Effect of Developmental Binocular Vision Abnormalities on Visual Vertigo Symptoms and Treatment Outcome.
abstract: OBJECTIVE
  Customized vestibular rehabilitation incorporating optokinetic (OK) stimulation improves visual vertigo (VV) symptoms; however, the degree of improvement varies among individuals. Binocular vision abnormalities (misalignment of ocular axis, ie, strabismus) may be a potential risk factor. This study aimed to investigate the influence of binocular vision abnormalities on VV symptoms and treatment outcome.
  
  
  METHODS
  Sixty subjects with refractory peripheral vestibular symptoms underwent an orthoptic assessment after being recruited for participation in an 8-week customized program incorporating OK training via a full-field visual environment rotator or video display, supervised or unsupervised. Treatment response was assessed at baseline and at 8 weeks with dynamic posturography, Functional Gait Assessment (FGA), and questionnaires for symptoms, symptom triggers, and psychological state. As no significant effect of OK training type was noted for any variables, data were combined and new groups identified on the basis of the absence or presence of a binocular vision abnormality.
  
  
  RESULTS
  A total of 34 among 60 subjects consented to the orthoptic assessment, of whom 8 of the 34 had binocular vision abnormalities and 30 of the 34 subjects completed both the binocular function assessment and vestibular rehabilitation program. No significant between-group differences were noted at baseline. The only significant between-group difference was observed for pre-/post-VV symptom change (P = 0.01), with significant improvements noted only for the group without binocular vision abnormalities (P < 0.0005). Common vestibular symptoms, posturography, and the FGA improved significantly for both groups (P < 0.05).
  
  
  CONCLUSIONS
  Binocular vision abnormalities may affect VV symptom improvement. These findings may have important implications for the management of subjects with refractory vestibular symptoms.Video Abstract available for insights from the authors regarding clinical implication of the study findings (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A115).
authors.affiliation: Centre of Human and Aerospace Physiology (M.P.), School of Biomedical Sciences, King's College London, London, United Kingdom; Department of Neuro-Ophthalmology (J.A., D.N.) and Department of Neuro-Otology (A.M.B., R.A.D.), National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (J.A., D.N.), London, United Kingdom; Save Sight Institute (C.L.F.), University of Sydney, Sydney, Australia; and Neuro-Otology Unit (A.M.B.), Division of Brain Sciences, Imperial College London, London, United Kingdom.
authors.forename: Marousa
authors.initials: M
authors.lastname: Pavlou
authors.forename: James
authors.initials: J
authors.lastname: Acheson
authors.forename: Despina
authors.initials: D
authors.lastname: Nicolaou
authors.forename: Clare L
authors.initials: CL
authors.lastname: Fraser
authors.forename: Adolfo M
authors.initials: AM
authors.lastname: Bronstein
authors.forename: Rosalyn A
authors.initials: RA
authors.lastname: Davies
mesh_terms: D000328:Adult; D000368:Aged; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D004856:Postural Balance / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D014717:Vertigo / Q000503:physiopathology / Q000534:rehabilitation*; D014786:Vision Disorders / Q000503:physiopathology / Q000534:rehabilitation*; D015348:Vision, Binocular / Q000502:physiology*