[{"key":"dc.contributor.author","value":"Small, Susan Anne","language":null},{"key":"dc.date.accessioned","value":"2011-02-03T21:45:22Z","language":null},{"key":"dc.date.available","value":"2011-02-03T21:45:22Z","language":null},{"key":"dc.date.issued","value":"2007","language":null},{"key":"dc.identifier.uri","value":"http:\/\/hdl.handle.net\/2429\/31066","language":null},{"key":"dc.description.abstract","value":"The purpose of this dissertation was to determine whether multiple auditory-state\r\nresponses (ASSRs) to bone-conduction stimuli can be used to investigate bone-conduction\r\nhearing, an essential part of any audiometric assessment. Infant bone-conduction testing methods,\r\nmaturation of bone-conduction hearing, and ipsilateral\/contralateral asymmetries in ASSRs were\r\nalso assessed. The results show that bone-conduction ASSRs can be used to estimate thresholds\r\nin infants and adults with normal hearing. It was also found that choice of electroencephalogram\r\n(EEG) conditioning and processing can avoid spurious ASSRs due to aliasing. Non-auditory\r\nASSRs (probably vestibular and indistinguishable from an auditory response) were also\r\nidentified for high-intensity air-conduction stimuli (problematic when diagnosing residual\r\nhearing). Investigation of infant testing methods on bone-conduction threshold shows that: (i)\r\nbone-oscillator coupling method (elastic-band vs. hand-held) has no effect on threshold, (ii) use\r\nof different oscillator locations on the temporal bone does not affect threshold but a forehead\r\nplacement results in elevated thresholds, and (iii) infants do not appear to have an occlusion\r\neffect (thus one can can assess with or without earphones). Young infants have much better low-frequency\r\nbone-conduction hearing compared to adults, which increases with maturation beyond\r\n24 months of age. Infant bone-conduction hearing is slightly poorer in the high frequencies,\r\nimproving significantly with age only at 2000 Hz. Within all infant groups, low-frequency\r\nthresholds are better than high-frequency thresholds; for adults, 500-Hz thresholds are poorer\r\nthan high frequencies and there is no difference among thresholds above 500 Hz. Bone-conducted\r\nsignals are much more effective for infants across frequency, especially at low\r\nfrequencies. Normal levels for bone-conduction hearing in young and older infants are proposed.\r\nIpsilateral\/contralateral asymmetries in air- and bone-conduction ASSRs are clearly present more often and are larger in infants compared to adults, and suggest that most infants have 10-30 dB of\r\ninteraural attenuation. These asymmetries have potential as a clinical tool for isolating the\r\ncochlea that is contributing to the response in infants. The results of these studies indicate that\r\ninfants can now be screened for normal bone-conduction hearing with ASSRs; however, infants\r\nwith hearing loss must be tested before elevated bone-conduction ASSRs thresholds can be\r\ninterpreted.","language":"en"},{"key":"dc.language.iso","value":"eng","language":"en"},{"key":"dc.publisher","value":"University of British Columbia","language":"en"},{"key":"dc.rights","value":"For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https:\/\/open.library.ubc.ca\/terms_of_use.","language":null},{"key":"dc.title","value":"Bone-conduction auditory steady-state responses","language":"en"},{"key":"dc.type","value":"Text","language":"en"},{"key":"dc.degree.name","value":"Doctor of Philosophy - PhD","language":"en"},{"key":"dc.degree.discipline","value":"Audiology and Speech Sciences","language":"en"},{"key":"dc.degree.grantor","value":"University of British Columbia","language":"en"},{"key":"dc.type.text","value":"Thesis\/Dissertation","language":"en"},{"key":"dc.description.affiliation","value":"Medicine, Faculty of","language":null},{"key":"dc.description.affiliation","value":"Audiology and Speech Sciences, School of","language":null},{"key":"dc.degree.campus","value":"UBCV","language":"en"},{"key":"dc.description.scholarlevel","value":"Graduate","language":"en"}]