title: A longitudinal functional MRI study of non-arteritic anterior ischaemic optic neuropathy patients.
abstract: BACKGROUND
  Non-arteritic anterior ischaemic optic neuropathy (NA-AION) can cause disabling visual loss and traditionally, visual prognosis has been considered poor, although recent studies have demonstrated improvements in visual acuity in about 30% of patients over time. The aim of the study was to determine whether there was significant cortical reorganisation with functional MRI (fMRI) after acute NA-AION by comparing affected individuals with healthy controls.
  
  
  METHODS
  9 patients with NA-AION were studied acutely and then after 1, 2, 3 and 6&emsp14;months. 23 healthy volunteers underwent scanning at least twice. At each time point, patients were assessed clinically and with fMRI. For the fMRI experiments, subjects underwent monocular visual stimulation (wearing goggles with flashing LED displays).
  
  
  RESULTS
  When stimulating the affected eye, occipital activation was reduced in patients compared with controls. Also, within the NA-AION group, activation in the right Brodmann areas (BA) 44 and 45 was seen during the early phase of the condition. The same areas were activated within the NA-AION group several months later for fellow eye stimulation. When the NA-AION and healthy control groups were formally compared however, these areas (BA 44/45) were not significantly different. NA-AION subjects did show greater activation in visual related areas compared with controls when stimulating the fellow eye. Visual acuity was correlated with more occipital cortex activation when stimulating the affected eye.
  
  
  CONCLUSIONS
  There is cortical re-organisation of the fMRI response in extra-visual areas, seen when both affected and fellow eyes are stimulated after NA-AION.
authors.affiliation: Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Aguirregomozcorta
authors.forename: Laura
authors.initials: L
authors.lastname: Mancini
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jenkins
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Hickman
authors.forename: Olga
authors.initials: O
authors.lastname: Ciccarelli
authors.forename: Gordon T
authors.initials: GT
authors.lastname: Plant
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thompson
authors.forename: Ahmed T
authors.initials: AT
authors.lastname: Toosy
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D005625:Frontal Lobe / Q000503:physiopathology*; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000503:physiopathology*; D018917:Optic Neuropathy, Ischemic / Q000503:physiopathology*; D010775:Photic Stimulation; D013997:Time Factors; D014792:Visual Acuity; D014794:Visual Fields