title: Electrophysiology and optical coherence tomography to evaluate Parkinson disease severity.
abstract: OBJECTIVE
  To evaluate correlations between visual evoked potentials (VEP), pattern electroretinogram (PERG), and macular and retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and the severity of Parkinson disease (PD).
  
  
  METHODS
  Forty-six PD patients and 33 age and sex-matched healthy controls were enrolled, and underwent VEP, PERG, and OCT measurements of macular and RNFL thicknesses, and evaluation of PD severity using the Hoehn and Yahr scale to measure PD symptom progression, the Schwab and England Activities of Daily Living Scale (SE-ADL) to evaluate patient quality of life (QOL), and disease duration. Logistical regression was performed to analyze which measures, if any, could predict PD symptom progression or effect on QOL.
  
  
  RESULTS
  Visual functional parameters (best corrected visual acuity, mean deviation of visual field, PERG positive (P) component at 50 ms -P50- and negative (N) component at 95 ms -N95- component amplitude, and PERG P50 component latency) and structural parameters (OCT measurements of RNFL and retinal thickness) were decreased in PD patients compared with healthy controls. OCT measurements were significantly negatively correlated with the Hoehn and Yahr scale, and significantly positively correlated with the SE-ADL scale. Based on logistical regression analysis, fovea thickness provided by OCT equipment predicted PD severity, and QOL and amplitude of the PERG N95 component predicted a lower SE-ADL score.
  
  
  CONCLUSIONS
  Patients with greater damage in the RNFL tend to have lower QOL and more severe PD symptoms. Foveal thicknesses and the PERG N95 component provide good biomarkers for predicting QOL and disease severity.
authors.affiliation: Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Garcia-Martin
authors.forename: Diego
authors.initials: D
authors.lastname: Rodriguez-Mena
authors.forename: Maria
authors.initials: M
authors.lastname: Satue
authors.forename: Carmen
authors.initials: C
authors.lastname: Almarcegui
authors.forename: Isabel
authors.initials: I
authors.lastname: Dolz
authors.forename: Raquel
authors.initials: R
authors.lastname: Alarcia
authors.forename: Maria
authors.initials: M
authors.lastname: Seral
authors.forename: Vicente
authors.initials: V
authors.lastname: Polo
authors.forename: Jose M
authors.initials: JM
authors.lastname: Larrosa
authors.forename: Luis E
authors.initials: LE
authors.lastname: Pablo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001369:Axons / Q000473:pathology*; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D011788:Quality of Life / Q000523:psychology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology
keywords: Parkinson disease; optical coherence tomography; pattern electroretinogram; quality of life; visual evoked potentials