title: Validation of mobile eye-tracking as novel and efficient means for differentiating progressive supranuclear palsy from Parkinson's disease.
abstract: BACKGROUND
  The decreased ability to carry out vertical saccades is a key symptom of Progressive Supranuclear Palsy (PSP). Objective measurement devices can help to reliably detect subtle eye movement disturbances to improve sensitivity and specificity of the clinical diagnosis. The present study aims at transferring findings from restricted stationary video-oculography (VOG) to a wearable head-mounted device, which can be readily applied in clinical practice.
  
  
  METHODS
  We investigated the eye movements in 10 possible or probable PSP patients, 11 Parkinson's disease (PD) patients, and 10 age-matched healthy controls (HCs) using a mobile, gaze-driven video camera setup (EyeSeeCam). Ocular movements were analyzed during a standardized fixation protocol and in an unrestricted real-life scenario while walking along a corridor.
  
  
  RESULTS
  The EyeSeeCam detected prominent impairment of both saccade velocity and amplitude in PSP patients, differentiating them from PD and HCs. Differences were particularly evident for saccades in the vertical plane, and stronger for saccades than for other eye movements. Differences were more pronounced during the standardized protocol than in the real-life scenario.
  
  
  CONCLUSIONS
  Combined analysis of saccade velocity and saccade amplitude during the fixation protocol with the EyeSeeCam provides a simple, rapid (<20 s), and reliable tool to differentiate clinically established PSP patients from PD and HCs. As such, our findings prepare the ground for using wearable eye-tracking in patients with uncertain diagnoses.
authors.affiliation: Department of Neurophysics, Philipps-University Marburg, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Marx
authors.forename: Gesine
authors.initials: G
authors.lastname: Respondek
authors.forename: Maria
authors.initials: M
authors.lastname: Stamelou
authors.forename: Stefan
authors.initials: S
authors.lastname: Dowiasch
authors.forename: Josef
authors.initials: J
authors.lastname: Stoll
authors.forename: Frank
authors.initials: F
authors.lastname: Bremmer
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Oertel
authors.forename: Günter U
authors.initials: GU
authors.lastname: Höglinger
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Einhäuser