title: Optical coherence tomography in parkinsonian syndromes.
abstract: OBJECTIVE
  Parkinson's disease (PD) and the atypical parkinsonian syndromes multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are movement disorders associated with degeneration of the central nervous system. Degeneration of the retina has not been systematically compared in these diseases.
  
  
  METHODS
  This cross-sectional study used spectral-domain optical coherence tomography with manual segmentation to measure the peripapillar nerve fiber layer, the macular thickness, and the thickness of all retinal layers in foveal scans of 40 patients with PD, 19 with MSA, 10 with CBS, 15 with PSP, and 35 age- and sex-matched controls.
  
  
  RESULTS
  The mean paramacular thickness and volume were reduced in PSP while the mean RNFL did not differ significantly between groups. In PSP patients, the complex of retinal ganglion cell- and inner plexiform layer and the outer nuclear layer was reduced. In PD, the inner nuclear layer was thicker than in controls, MSA and PSP. Using the ratio between the outer nuclear layer and the outer plexiform layer with a cut-off at 3.1 and the additional constraint that the inner nuclear layer be under 46 µm, we were able to differentiate PSP from PD in our patient sample with a sensitivity of 96% and a specificity of 70%.
  
  
  CONCLUSIONS
  Different parkinsonian syndromes are associated with distinct changes in retinal morphology. These findings may serve to facilitate the differential diagnosis of parkinsonian syndromes and give insight into the degenerative processes of patients with atypical parkinsonian syndromes.
authors.affiliation: Department of Neurology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany. phil.albrecht@gmail.com
authors.forename: Philipp
authors.initials: P
authors.lastname: Albrecht
authors.forename: Ann-Kristin
authors.initials: AK
authors.lastname: Müller
authors.forename: Martin
authors.initials: M
authors.lastname: Südmeyer
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferrea
authors.forename: Marius
authors.initials: M
authors.lastname: Ringelstein
authors.forename: Eva
authors.initials: E
authors.lastname: Cohn
authors.forename: Orhan
authors.initials: O
authors.lastname: Aktas
authors.forename: Thomas
authors.initials: T
authors.lastname: Dietlein
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lappas
authors.forename: Andreas
authors.initials: A
authors.lastname: Foerster
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Hartung
authors.forename: Alfons
authors.initials: A
authors.lastname: Schnitzler
authors.forename: Axel
authors.initials: A
authors.lastname: Methner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000473:pathology*; D012160:Retina / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods*