title: An investigation into the clinical utility of ipsilateral/contralateral asymmetries in bone-conduction auditory steady-state responses.
abstract: OBJECTIVE
  To determine whether ipsilateral/contralateral asymmetries in the bone-conduction (BC) ASSR are robust enough in infants to be used clinically to isolate the test ear.
  
  
  METHODS
  Retrospective investigation of three two-channel BC ASSR datasets.
  
  
  METHODS
  Forty-eight adults (mean age 26.7 years), 49 infants (mean age 29.6 weeks).
  
  
  METHODS
  BC ASSR stimuli were presented as amplitude/frequency modulated sinusoidal tones with carrier frequencies of 500, 1000, 2000, and 4000 Hz (-10 to 45 dB HL).
  
  
  RESULTS
  Infants showed greater differences in ipsilateral/contralateral mean amplitudes and phase delays for all experimental conditions compared to adults. Ninety percent of infants had ipsilateral/contralateral asymmetries at 500 and 4000 Hz (20-35 dB HL) using an "amplitude or phase delay" criterion, and at 4000 Hz (20-25 dB HL) using an "amplitude and phase delay" criterion.
  
  
  CONCLUSIONS
  As ipsilateral/contralateral asymmetries are not consistently present for 1000- and 2000-Hz BC ASSRs in infants, clinical masking would be needed at these frequencies to isolate the test ear. For 500- and 4000-Hz BC ASSRs, the accuracy of using these asymmetries requires clinical confirmation in a group of infants with hearing loss.
authors.affiliation: School of Audiology & Speech Sciences, University of British Columbia , Vancouver , Canada.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Small
authors.forename: Alison
authors.initials: A
authors.lastname: Love
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold; D001844:Bone Conduction; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011930:Reaction Time; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D055815:Young Adult
keywords: Auditory steady-state response; bone-conduction ASSR; infant bone-conduction hearing; ipsilateral/contralateral asymmetry