Bone Conduction and the Middle Ear

Stenfelt, Stefan

doi:10.1007/978-1-4614-6591-1_6

Cited by 19 publications

(20 citation statements)

References 144 publications

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“…Hearing by BC is usually described as sound power transmitted through the body (Stenfelt 2013). But the exact pathways conveying the sound power have not been clarified.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Chang

Kim

Stenfelt

2018

Biomech Model Mechanobiol

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Bone conduction (BC) sound is the perception of sound transmitted in the skull bones and surrounding tissues. To better understand BC sound perception and the interaction with surrounding tissues, the power transmission of BC sound is investigated in a three-dimensional finite-element model of a whole human head. BC sound transmission was simulated in the FE model and the power dissipation as well as the power flow following a mechanical vibration at the mastoid process behind the ear was analyzed. The results of the simulations show that the skull bone (comprises the cortical bone and diploë) has the highest BC power flow and thereby provide most power transmission for BC sound. The soft tissues was the second most important media for BC sound power transmission, while the least BC power transmission is through the brain and the surrounding cerebrospinal fluid (CSF) inside the cranial vault. The vibrations transmitted in the skull are mainly concentrated at the skull base when the stimulation is at the mastoid. Other vibration transmission pathways of importance are located at the occipital bone at the posterior side of the head while the transmission of sound power through the face, forehead and vertex is minor. The power flow between the skull bone and skull interior indicate that some BC power is transmitted to and from the skull interior but the transmission of sound power through the brain seem to be minimal and only local to the brain-bone interface.

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“…Hearing by BC is usually described as sound power transmitted through the body (Stenfelt 2013). But the exact pathways conveying the sound power have not been clarified.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Chang

Kim

Stenfelt

2018

Biomech Model Mechanobiol

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“…A Weber test was performed with forehead placement of the bone oscillator at 250, 500, and 1000 Hz at 10 dB SL re: pure tone air conduction thresholds to determine the ear with the better cochlear response at each frequency because conductive hearing loss was ruled out. A method described by Stenfelt (2012) was used in which placement was determined according to the site of lateralization identified at a minimum of two out of three test frequencies. If this condition was not met because of midline identification, then the placement site was randomly chosen.…”

Section: Methodsmentioning

confidence: 99%

Accounting for the Occlusion Effect with Insert Earphones

et al. 2018

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There are clinical implications associated with knowing when the occlusion effect (OE) must be accounted for during bone conduction (BC) testing because spurious results can occur when errors are made in this regard. The amount of OE produced when insert earphones (IEs) are used varies in the literature; thus, further investigation is warranted.The purpose of this project was to determine the OE during BC threshold measurements under the following occluding conditions used clinically: when using partial insertion (PI) versus full insertion (FI) depth and when occluding one versus both ears.A descriptive within-subjects design was used in this study.Twenty-two adults with mean four-frequency pure tone averages of 24 dB HL, aged 40–83 yr, participated.BC thresholds were obtained at 250, 500, and 1000 Hz under seven conditions: (1) both ears unoccluded, (2) left ear occluded with PI, (3) right ear occluded with PI, (4) both ears occluded with PI, (5) left ear occluded with FI, (6) right ear occluded with FI, (7) both ears occluded with FI. For PI, one half of the length of the IE was beyond the opening of the ear canal. For FI, the lateral edge of the foam insert was flush with the entrance to the ear canal.Mean OEs were compared with previously published data. In addition, variability in the data was examined using frequency distribution plots as well as cumulative frequency and percentile values.Mean OEs of 5–13 dB were present in all but the FI condition at 1000 Hz where the OE was <3 dB. Differences between PI and FI conditions were present at each frequency measured, irrespective of whether one or both ears were occluded. The shifts in threshold were consistently more prevalent and greater for the PI than the FI conditions overall. Mean differences between the one-ear and both-ears conditions were not clinically significant. Clinically significant variability in the data was noted, except when comparing the one-ear versus both-ears conditions.Occluding the ear during initial BC measurements may artificially improve the thresholds and create or exaggerate an air-bone gap. Thus, initial BC testing should be performed unoccluded at 250, 500, and 1000 Hz. There is a need to account for the OE even when the IE is flush with the ear canal to avoid insufficient masking.

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“…Several authors have presented the BC sound transmission through the skull. They primarily show the transcranial BC sound transmission, but do not elude on the BC pathways or directions (Stenfelt et al, 2000, 2013Stenfelt and Goode, 2005b;Stenfelt, 2011Stenfelt, , 2012. In this study, the BC power flux through the pathways were analyzed.…”

Section: Results and Conclusionmentioning

confidence: 99%

“…Through the studies of the BC sound, it is understood that the BC sound transmission in the human head is complex: not only the skull bone, but also many other structures are involved in the propagation of BC sound (Stenfelt, 2013). Nowadays, more experimental data which investigated BC sound transmission and the responses of the BC stimulation in cadaver heads and living humans, have been reported in the literature (Stenfelt and Goode, 2005b;Håkansson et al, 1986Håkansson et al, , 1994Håkansson et al, , 2008Eeg-Olofsson et al, 2008, 2013Stenfelt, 2012;Reinfeldt et al, 2013). However, although the published data from human heads increased, the complexity of the experimental manipulations still limit the amount of possible experiments.…”

Section: Background Of Bone-conducted Soundmentioning

confidence: 99%

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A Finite Element Model of the Human Head for Simulation of Bone-conducted Sound

Chang¹

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Bone conduction (BC) is usually understood as the hearing sensation based on the vibrations of the skull bone and surrounding tissues. The fact that vibration of the skull bones can result in a sound percept has been known for a long time. However, it is difficult to give a general definition of BC sound. Normally, BC sound is described as the sound energy transmitted through the body (comprising the solid and fluid parts) then the outer, middle and inner ear are involved and finally produce a perception of sound.

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Bone Conduction and the Middle Ear

Cited by 19 publications

References 144 publications

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Accounting for the Occlusion Effect with Insert Earphones

A Finite Element Model of the Human Head for Simulation of Bone-conducted Sound

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