title: Using visual evoked potentials for the early detection of amnestic mild cognitive impairment: a pilot investigation.
abstract: OBJECTIVE
  Amnesic mild cognitive impairment (MCIa) is often characterized as an early stage of Alzheimer's dementia (AD). The latency of the P2, an electroencephalographic component of the flash visual evoked potential (FVEP), is significantly longer in those with AD or MCIa when compared with controls. The present investigation examined the diagnostic accuracy of several FVEP-P2 procedures in distinguishing people with MCIa and controls.
  
  
  METHODS
  The latency of the FVEP-P2 was measured in participants exposed to a single flash condition and five double flash conditions. The double flash conditions had different inter-stimulus intervals between the pair of strobe flashes.
  
  
  RESULTS
  Significant group differences were observed in the single flash and two of the double flash conditions. One of the double flash conditions (100 ms) displayed a higher predictive accuracy than the single flash condition, suggesting that this novel procedure may have more diagnostic potential. Participants with MCIa displayed similar P2 latencies across conditions, while controls exhibited a consistent pattern of P2 latency differences. These differences demonstrate that the double stimulation procedure resulted in a measurable refractory effect for controls but not for those with MCIa.
  
  
  CONCLUSIONS
  The pattern of P2 group differences suggests that those with MCIa have compromised cholinergic functioning that results in impaired visual processing. Results from the present investigation lend support to the theory that holds MCIa as an intermediate stage between normal healthy aging and the neuropathology present in AD. Measuring the FVEP-P2 during several double stimulation conditions could provide diagnostically useful information about the health of the cholinergic system.
authors.affiliation: Cognitive Neuroscience Laboratory, University of North Carolina, Charlotte, NC, USA.
authors.forename: Spencer T
authors.initials: ST
authors.lastname: Fix
authors.forename: James E
authors.initials: JE
authors.lastname: Arruda
authors.forename: Frank
authors.initials: F
authors.lastname: Andrasik
authors.forename: Jameson
authors.initials: J
authors.lastname: Beach
authors.forename: Kevin
authors.initials: K
authors.lastname: Groom
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000503:physiopathology; D042241:Early Diagnosis; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D010865:Pilot Projects; D011930:Reaction Time / Q000502:physiology
keywords: AD; Alzheimer; FVEP; MCI; P2; acetylcholine; flash visual evoked potential; mild cognitive impairment