title: [A comparison of low-chirp- and notched-noise-evoked auditory brainstem response].
abstract: BACKGROUND
  In order to obtain a low-frequency specific auditory brainstem response (ABR) there are less stimuli that plege a satisfying accordance with the ABR threshold and the behavioural threshold. This study investigates the so called low-chirp-ABR as to predict a low-frequency-amblyacousia and compares it to the notched-noise-500 Hz-ABR.
  
  
  METHODS
  We evaluated behavioural and ABR thresholds to a low-chirp respectively a 500 Hz tone presented in notched noise masking from 32 patients with a severe hearing loss at low-frequencies and 28 patients with normal hearing.
  
  
  RESULTS
  The average difference ± single standard deviation between low-chirp-ABR and behavioural threshold is 1.53 dB ± 7.68 dB in the group of patient with low-frequency hearing loss and 2.55 dB ± 5.46 dB in the group of normal hearing. On the contrary the difference between notched-noise-500 Hz- and behavioural thereshold averages 2.67 dB ± 9.29 dB (low-frequency hearing loss) respectively 8.82 dB ± 7.90 dB (normal hearing). In order to verify the equivalence between the several methods we did a equivalence test that shows that low-chip-ABR and behavioural threshold can be considered as equal to obtain a low-frequency threshold. In contrast the comparison of notched-noise-500 Hz-ABR and behavioural threshold proves no equivalence.
  
  
  CONCLUSIONS
  We detected a significant equivalence between low-chirp-ABR and pure-tone audiometric. The ABR to a low-chirp stimulus seems to be rather precise in contrast to the notched-noise-500 Hz-evoked-ABR in order to diagnose a low-frequency-hearing loss.
authors.affiliation: Hals-Nasen-Ohrenheilunde, Universitätsklinik Bonn, Bonn, Germany. laura.muehlenberg@ukb.uni-bonn.de
authors.forename: L
authors.initials: L
authors.lastname: Mühlenberg
authors.forename: G
authors.initials: G
authors.lastname: Schade
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology; D003056:Cochlear Nerve / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D011571:Psychoacoustics; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography