title: Comparing auditory brainstem responses (ABRs) to toneburst and narrow band CE-chirp in young infants.
abstract: OBJECTIVE
  The difference of characteristics (latency and amplitude) between toneburst and narrow CE-chirp stimuli on ABR recording was analyzed in normal hearing infants.
  
  
  METHODS
  500, 1000, 2000 and 4000 Hz toneburst and narrow band CE-chirp auditory brainstem responses (ABRs) were recorded in 40 normal-hearing infants. The amplitude and latency parameters of the ABR were collected for each of the four stimulus levels: 80, 60, 40, and 20 dB nHL. Both stimuli started from 80 dB nHL using alternating polarity and the rates were both 27.1/s.
  
  
  RESULTS
  The toneburst latencies are greater than narrow band CE-chirp latencies for all intensities at 500, 1000 and 2000 Hz (p < 0.001). However, at 4000 Hz this difference was not significant. At 500 Hz, wave V amplitude is larger for toneburst than narrow CE-chirp (p < 0.001) in 80 dB nHL. The difference between the two stimuli in 60 dB nHL was not significant (p = 0.495) and at 40 and 20 dB nHL the wave V narrow band CE-chirp amplitude is greater than toneburst amplitude (p < 0.001). At 1000, 2000 and 4000 Hz there is no difference between the wave V toneburst and narrow band CE-chirp amplitudes at 80 dB nHL (p = 0.940; p = 0.776 and p = 0.217 respectively). On the other hand, in the levels to 60, 40 and 20 dB nHL, narrow band CE-chirp amplitudes are larger than toneburst amplitude (p < 0.001).
  
  
  CONCLUSIONS
  Narrow band CE-chirp ABRs generates shorter latencies than the toneburst ABRs, especially to low frequencies. Higher amplitudes were found with narrow band CE-chirp stimuli for all frequencies tested, except to high levels.
authors.affiliation: School of Speech-Language Pathology and Audiology, Pontifícia Universidade Católica de São Paulo - PUC-SP, São Paulo, SP, Brazil. gabrielaivo@hotmail.com
authors.forename: Gabriela Ribeiro Ivo
authors.initials: GR
authors.lastname: Rodrigues
authors.forename: Natália
authors.initials: N
authors.lastname: Ramos
authors.forename: Doris Ruthi
authors.initials: DR
authors.lastname: Lewis
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D001309:Auditory Threshold / Q000502:physiology; D015331:Cohort Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D007223:Infant; D008144:Loudness Perception / Q000502:physiology*; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D010898:Pitch Perception / Q000502:physiology*; D011446:Prospective Studies; D011930:Reaction Time; D012016:Reference Values
keywords: Auditory brain stem responses; Children; Evoked response audiometry; Hearing thresholds