title: Automatic detection of frequency changes depends on auditory stimulus intensity.
abstract: OBJECTIVE
  A cortical cognitive auditory evoked potential, mismatch negativity (MMN), reflects automatic discrimination and echoic memory functions of the auditory system. For this study, we examined whether this potential is dependent on the stimulus intensity.
  
  
  METHODS
  The MMN potentials were recorded from 10 subjects with normal hearing using a sine tone of 1000 Hz as the standard stimulus and a sine tone of 1141 Hz as the deviant stimulus, with probabilities of 90% and 10%, respectively. The intensities were 40, 50, 60, 70, and 80 dB HL for both standard and deviant stimuli in separate blocks.
  
  
  RESULTS
  Stimulus intensity had a statistically significant effect on the mean amplitude, rise time parameter, and onset latency of the MMN.
  
  
  CONCLUSIONS
  Automatic auditory discrimination seems to be dependent on the sound pressure level of the stimuli.
authors.affiliation: Department of Audiology, Turku University Hospital, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Salo
authors.forename: A H
authors.initials: AH
authors.lastname: Lang
authors.forename: O
authors.initials: O
authors.lastname: Aaltonen
authors.forename: K
authors.initials: K
authors.lastname: Lertola
authors.forename: T
authors.initials: T
authors.lastname: Kärki
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology; D001330:Electronic Data Processing; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012984:Software; D013997:Time Factors