title: Visual motion event related potentials distinguish aging and Alzheimer's disease.
abstract: BACKGROUND
  Aging and Alzheimer's disease (AD) disrupt visuospatial processing and visual motion evoked potentials in a manner linked to navigational deficits.
  
  
  OBJECTIVE
  Our goal is to determine if aging and AD have distinct effects on visual cortical motion processing for navigation.
  
  
  METHODS
  We recorded visual motion event related potentials (ERPs) in young (YNC) and older normal controls (ONC), and early AD patients (EADs) who viewed rapidly changing optic flow stimuli that simulate naturalistic changes in heading direction, like those that occur when following a path of self-movement through the environment. After a random series of optic flow stimuli, a vertical motion stimulus was presented to verify sustained visual attention by demanding a rapid push-button response.
  
  
  RESULTS
  Optic flow evokes robust ERPs that are delayed in aging and diminished in AD. The interspersed vertical motion stimuli yielded shorter N200 latencies in EADs, matching those in ONCs, but the EADs' N200 amplitudes remained small.
  
  
  CONCLUSIONS
  Aging and AD have distinct effects on visual sensory processing: aging delays evoked response, whereas AD diminishes responsiveness.
authors.affiliation: Departments of Neurology, Brain and Cognitive Sciences, Neurobiology and Anatomy, Ophthalmology, and the Center for Visual Science, The University of Rochester Medical Center, Rochester, NY 14642-0673, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernandez
authors.forename: Anthony
authors.initials: A
authors.lastname: Monacelli
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Duffy
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D001921:Brain / Q000502:physiology / Q000503:physiopathology; D016022:Case-Control Studies; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation