Biomedical subjects

B E Håkansson

Publications and source records attributed to B E Håkansson.

4 recordsLinked to original sources

PubMed1999

Sensitivity to bone-conducted sound: excitation of the mastoid vs the teeth.

The sensitivity of nine subjects to bone-conducted sound was measured at three positions: osseointegrated percutaneous titanium implants in the temporal bone, the skin-covered mastoid and the teeth. Voltage levels supplied to a bone-anchored hearing aid (BAHA) transducer and to an Oticon bone-transducer were measured and the thresholds obtained at the three positions were compared. Using the mechanical impedance of the teeth, the parameters of a first order model for the vibration transmission through the teeth was calculated. Also, the equivalent force thresholds were calculated from the voltage threshold levels. The sensitivity to bone-conducted sound, for both voltage and force thresholds, conformed fairly well at the three positions for frequencies below 1 kHz; however, above 1 kHz, bone-conducted sound applied at the titanium implant becomes more sensitive than at the two other positions investigated. It was concluded that the teeth can be used for the application of bone-conducted sound, in particular for pre-operative assessment of a BAHA and to facilitate service and quality control of such a hearing device.

Adult↗

PubMed1998

A miniaturized artificial mastoid using a skull simulator.

A miniaturized artificial mastoid of size and weight that allow calibration and measurement of bone conduction hearing aids in a conventional audiometric soundproof box has been developed. Its level of mechanical impedance corresponds to the standard IEC 373 (1990) within the frequency range 250 Hz to 8 kHz. The miniaturized artificial mastoid consists of three parts: coupler, skull simulator (TU-1000), and an external electrical correction filter. The coupler is a highly damped mass-spring system designed to give the miniaturized artificial mastoid mechanical impedance in accordance with the standard IEC 373 (1990). It was found that the miniaturized artificial mastoid yielded results that are in correspondence with results obtained with the Brüel & Kjaer type 4930 artificial mastoid for frequencies above 450 Hz. Thus, at these frequencies, the miniaturized artificial mastoid can be used for audiometer calibration as well as measurement of bone conduction hearing aids.

Bone Conduction↗

PubMed1997

The bone-anchored hearing aid: reference quantities and functional gain.

One of the most important parameters of a hearing aid is its gain characteristics. Under ideal circumstances, the gain and the functional gain (FG) are the same for an air conduction device. This is not the case, however, with bone conduction devices, e.g., the bone-anchored hearing aid (BAHA). In this article, the relation between the gain and the FG is derived for bone conduction devices including the BAHA. Reference quantities used when measuring bone conduction devices also are presented.

Auditory Threshold↗

PubMed1994

The bone-anchored hearing aid: principal design and audiometric results.

The principle of the bone-anchored hearing aid (BAHA) is simple: sound vibrations are directly transmitted to the skull bone via a skin-penetrating titanium implant, and then are further transmitted to the cochlea, bypassing the middle ear. The present paper summarized the audiometric results from 122 patients with an average follow-up time of 5.6 years. When herein-suggested indications for treatment with the bone-anchored sound processor HC 300 are followed, the success rate is very high. The improved quality of life reported by the patients is a combination of improved quality of sound (warble tone threshold, speech reception threshold, and discrimination in noise), improved comfort, and relief from middle ear and ear canal disease occasioned by conventional hearing aids.

Audiometry↗