title: Perceptual relearning of binocular fusion after hypoxic brain damage: four controlled single-case treatment studies.
abstract: OBJECTIVE
  Hypoxic brain damage is characterized by widespread, diffuse-disseminated brain lesions, which may cause severe disturbances in binocular vision, leading to diplopia and loss of stereopsis, for which no evaluated treatment is currently available. The study evaluated the effects of a novel binocular vision treatment designed to improve binocular fusion and stereopsis as well as to reduce diplopia in patients with cerebral hypoxia.
  
  
  METHODS
  Four patients with severely reduced convergent fusion, stereopsis, and reading duration due to hypoxic brain damage were treated in a single-subject baseline design, with three baseline assessments before treatment to control for spontaneous recovery (pretherapy), an assessment immediately after a treatment period of 6 weeks (posttherapy), and two follow-up tests 3 and 6 months after treatment to assess stability of improvements. Patients received a novel fusion and dichoptic training using 3 different devices designed to slowly increase fusional and disparity angle.
  
  
  RESULTS
  After the treatment, all 4 patients improved significantly in binocular fusion, subjective reading duration until diplopia emerged, and 2 of 4 patients improved significantly in local stereopsis. No significant changes were observed during the pretherapy baseline period and the follow-up period, thus ruling out spontaneous recovery and demonstrating long-term stability of treatment effects.
  
  
  CONCLUSIONS
  This proof-of-principle study indicates a substantial treatment-induced plasticity after hypoxia in the relearning of binocular vision and offers a viable treatment option. Moreover, it provides new hope and direction for the development of effective rehabilitation strategies to treat neurovisual deficits resulting from hypoxic brain damage.
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Anna-Katharina
authors.initials: AK
authors.lastname: Schaadt
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Lena
authors.initials: L
authors.lastname: Schmidt
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Caroline
authors.initials: C
authors.lastname: Kuhn
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Miriam
authors.initials: M
authors.lastname: Summ
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Michaela
authors.initials: M
authors.lastname: Adams
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Ruta
authors.initials: R
authors.lastname: Garbacenkaite
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Eva
authors.initials: E
authors.lastname: Leonhardt
authors.affiliation: Clinical Neuropsychology Unit, Saarland University.
authors.forename: Stefan
authors.initials: S
authors.lastname: Reinhart
authors.affiliation: Saarland University, Clinical Neuropsychology Unit.
authors.forename: Georg
authors.initials: G
authors.lastname: Kerkhoff
mesh_terms: D000328:Adult; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002534:Hypoxia, Brain / Q000150:complications*; D008297:Male; D009483:Neuropsychological Tests; D009988:Orthoptics / Q000379:methods; D010468:Perceptual Disorders / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D016896:Treatment Outcome; D014786:Vision Disorders / Q000503:physiopathology / Q000534:rehabilitation*; D015348:Vision, Binocular / Q000502:physiology*; D055815:Young Adult