Document Detail

Effective Masking Levels for Bone Conduction Auditory Steady State Responses in Infants and Adults With Normal Hearing.
MedLine Citation:
PMID:  21926629     Owner:  NLM     Status:  Publisher    
OBJECTIVE:: To obtain ear-specific bone conduction thresholds, masking of the nontest ear is often required. Bone conduction masking has not been formally investigated for infants assessed physiologically. The objective of this study was to determine effective masking levels (EMLs) for auditory steady state responses (ASSRs) elicited by bone-conducted stimuli in a group of normal-hearing infants and adults. DESIGN:: Participants were 15 infants younger than 6 mo and 15 adults, all with normal hearing. EML was defined as the lowest level of a binaural air-conducted masker that resulted in absent bone conduction ASSRs. Stimuli were single bone-conducted tones that were 100% amplitude modulated and 25% frequency modulated at 85 and 101 for 1000 and 4000 Hz, respectively. The stimuli were calibrated in dB HL (ANSI S3.6-1996) and expressed in dB HL or dB SL (dB relative to mean bone conduction ASSR thresholds reported in a previous study). The maskers were 1 and 4 kHz narrowband noise generated by a clinical audiometer. Unmasked and masked ASSRs were obtained for each participant. Real ear-to-coupler differences (RECDs) were also obtained for each participant and were used to convert masker dB SPL measured in the coupler to dB SPL in the individual ear canal. RESULTS:: Infant EMLs for ASSRs elicited to bone-conducted stimuli in dB HL were 6 to 7 dB higher and 8 to 10 dB lower for 1000 and 4000 Hz, respectively, compared with adults. When masker was adjusted for RECDs, infant EMLs were 12 dB higher at 1000 Hz and similar at 4000 Hz compared with adults. When the stimulus levels were corrected for the mean differences in ASSR bone conduction thresholds between infants and adults and the masker levels adjusted for RECDs, infants had lower EMLs at 1000 Hz and equal EMLs at 4000 Hz, in comparison to adults. Frequency- and level-dependent effects on ASSR amplitude due to masking were found and differed between infants and adults. CONCLUSIONS:: Our findings indicate that there are frequency- and level-dependent infant-adult differences in EMLs for bone conduction ASSRs and confirm that a 1000 Hz stimulus is 12 dB more effective for infants compared with adults. The following infant preliminary masking levels for bone conduction stimuli are recommended: (i) 1000 Hz: 48 and 58 dB SPL at 15 and 25 dB HL, respectively, and (ii) 4000 Hz: 40 and 45 dB SPL at 25 and 35 dB HL, respectively.
Erin E Hansen; Susan A Small
Related Documents :
24482309 - Nasal versus oral aerosol delivery to the "lungs" in infants and toddlers.
16675909 - Obstetric uterine rupture of the unscarred uterus: a twenty-year clinical analysis.
8085449 - Nursery neurobiologic risk score as a predictor of mortality in premature infants.
16518609 - Onset of vacuum-related complaints in neonates.
94509 - Fanconi's anemia: the preanemic phase.
25493679 - Nasal septum injury in preterm infants using nasal prongs.
16675269 - Abnormal deep grey matter development following preterm birth detected using deformatio...
8537569 - Maternal intake of cruciferous vegetables and other foods and colic symptoms in exclusi...
6470169 - Plasma ionised calcium in preterm infants: comparison with adults.
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-9-15
Journal Detail:
Title:  Ear and hearing     Volume:  -     ISSN:  1538-4667     ISO Abbreviation:  -     Publication Date:  2011 Sep 
Date Detail:
Created Date:  2011-9-19     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005585     Medline TA:  Ear Hear     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
School of Audiology and Speech Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Electrophysiological measurement of binaural beats: effects of primary tone frequency and observer ...
Next Document:  Expectancy and readiness-based predictors of treatment uptake among the urban poor living with HIV.