title: Driving with hemianopia: III. Detection of stationary and approaching pedestrians in a simulator.
abstract: OBJECTIVE
  To compare blind-side detection performance of drivers with homonymous hemianopia (HH) for stationary and approaching pedestrians, initially appearing at small (4°) or large (14°) eccentricities in a driving simulator. While the stationary pedestrians did not represent an imminent threat, as their eccentricity increased rapidly as the vehicle advanced, the approaching pedestrians maintained a collision course with approximately constant eccentricity, walking or running, toward the travel lane as if to cross.
  
  
  METHODS
  Twelve participants with complete HH and without spatial neglect pressed the horn whenever they detected a pedestrian while driving along predetermined routes in two driving simulator sessions. Miss rates and reaction times were analyzed for 52 stationary and 52 approaching pedestrians.
  
  
  RESULTS
  Miss rates were higher and reaction times longer on the blind than the seeing side (P < 0.01). On the blind side, miss rates were lower for approaching than stationary pedestrians (16% vs. 29%, P = 0.01), especially at larger eccentricities (20% vs. 54%, P = 0.005), but reaction times for approaching pedestrians were longer (1.72 vs. 1.41 seconds; P = 0.03). Overall, the proportion of potential blind-side collisions (missed and late responses) was not different for the two paradigms (41% vs. 35%, P = 0.48), and significantly higher than for the seeing side (3%, P = 0.002).
  
  
  CONCLUSIONS
  In a realistic pedestrian detection task, drivers with HH exhibited significant blind-side detection deficits. Even when approaching pedestrians were detected, responses were often too late to avoid a potential collision.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
authors.forename: Concetta F
authors.initials: CF
authors.lastname: Alberti
authors.forename: Eli
authors.initials: E
authors.lastname: Peli
authors.forename: Alex R
authors.initials: AR
authors.lastname: Bowers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001334:Automobile Driving; D003198:Computer Simulation; D005260:Female; D006423:Hemianopsia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D011930:Reaction Time / Q000502:physiology*; D015348:Vision, Binocular / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: detection rates; driving; response times