| 11. |
- Grenner, Jan, et al.
(author)
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A comparison of wind noise in four hearing instruments
- 2000
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In: Scandinavian Audiology. - : Informa UK Limited. - 0105-0397. ; 29:3, s. 171-174
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Journal article (peer-reviewed)abstract
- Wind noise was measured in four behind-the-ear hearing instruments with different microphone openings. A silent airflow of 7 m/s was directed toward the ear of a Kemar head and the resulting wind noise was measured. The amplification was set to an insertion gain of 35 dB at 1.6 kHz. The wind noise amplitude at the position of the drum ranged from 84 to 97 dB(A). The hearing instrument with a partially covered microphone entrance proved best, whereas one with an open microphone entrance had the poorest performance. A reduction in wind noise of 6-17 dB could be achieved in all hearing instruments by using a simple windscreen made of Styrofoam. The windscreen affected the frequency response by less than 2 dB. By subtracting the insertion gain from the wind noise, an equivalent wind noise could be presented as a function of frequency. A considerable difference was found between the wind noise sensitivity in different hearing instruments. All could be improved by a windscreen without adversely affecting the frequency response.
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| 12. |
- Grenner, Jan, et al.
(author)
-
Action potential threshold elevation in the guinea-pig as a function of impact noise exposure energy
- 1988
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In: Audiology. - : Informa UK Limited. - 0020-6091. ; 27:6, s. 356-366
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Journal article (peer-reviewed)abstract
- Eighteen groups of guinea pigs were exposed to a simulated impact noise for periods of 1.5-24 h. The peak level was kept constant at 131.5 dB and the repetition rate was varied to give seven different equivalent levels (Leq) between 96 and 117 dB. The auditory thresholds were assessed by electrocochleography after 1 month and compared with those of a control group. Significant damage occurred even at the lowest exposure energy used. When the total exposure energy was expressed on a decibel scale, the threshold elevation (1-10 kHz) increased 1.07 dB for each decibel increase in the exposure energy, regardless of the combination of Leq and exposure time. The results of the study thus support the equal-energy hypothesis under these conditions.
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| 13. |
- Grenner, Jan, et al.
(author)
-
AP threshold elevation in the guinea pig following exposure to a broadband noise
- 1989
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 86:6, s. 2223-2228
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Journal article (peer-reviewed)abstract
- Sixty guinea pigs were exposed to a steady-state broadband noise with a falling frequency spectrum. The sound-pressure level was varied between 96 and 117 dB SPL, and the duration of the exposure was varied from 3 to 12 h. After 4-5 weeks, the auditory thresholds were determined by electrocochleography at 14 frequencies, and the results were compared with a control group. With increasing sound-pressure level, the thresholds became elevated at all frequencies. The maximum threshold elevation also exhibited a slight shift toward higher frequencies. With increasing exposure time, the threshold elevations increased and shifted into the high-frequency region, whereas the low-frequency region was less affected. Linear regression analysis showed that the average threshold elevation between 1 and 20 kHz did not deviate from that predicted by the equal-energy hypothesis. However, the high-frequency loss at 5-20 kHz was very dependent on the exposure time, whereas the 1- to 4-kHz loss was not. There was no sign of any critical intensity with sudden increments in threshold elevation.
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| 14. |
- Grenner, Jan
(author)
-
Comments on Zazzio's Hyperacusis Study.
- 2012
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In: Photomedicine and Laser Surgery. - : Mary Ann Liebert Inc. - 1549-5418 .- 1557-8550. ; 30:7, s. 400-400
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Journal article (peer-reviewed)
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| 15. |
- Grenner, Jan, et al.
(author)
-
Hearing thresholds in four-year-old children with weak or no transient-evoked otoacoustic emissions
- 1997
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In: Scandinavian Audiology. - : Informa UK Limited. - 0105-0397. ; 26:2, s. 107-111
-
Journal article (peer-reviewed)abstract
- Play audiometry is part of the general developmental screening covering 4-year-old children in the city of Malmo (Sweden). In an open study, 10% of the cohort was tested with transient-evoked otoacoustic emissions (TEOAEs), using the ILO88 system. The aim was to reveal a hearing loss exceeding 25 dB HL in 4-year-old children. As the first step in determining whether emissions can be used as an efficient method of screening for hearing loss, 295 children were tested with TEOAEs. Audiometry was performed in 160 children. Audiometry was not performed if the TEOAEs were strong (> or = 10 dB SPL) in both ears. In the group with TEOAEs of 8.8dB SPL or greater, all ears tested with audiometry had a pure-tone average (PTA) of 25 dB HL or better. Twenty-one percent of the ears had TEOAEs < or = 0 dB SPL. Only 9% of the ears had a hearing threshold exceeding 25 dB HL (PTA). In conclusions, the number of pathological TEOAE results was much larger than the number of pathological audiograms, making TEOAEs too sensitive to use as a single screening test, but the method may be used as first-line screening.
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| 16. |
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| 17. |
- Grenner, Jan, et al.
(author)
-
Long-term measurements using home audiometry with Békésy’s technique
- 2017
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In: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 56:3, s. 202-211
-
Journal article (peer-reviewed)abstract
- Objective: To examine the efficacy of fixed-frequency Békésy’s home audiometry to assess hearing fluctuation and treatment outcomes in patients with subjectively fluctuating hearing loss. Design: SMAPH, a software audiometry program for Windows, was installed and calibrated on laptop computers. Békésy’s audiometry was carried out daily in the patients’ homes, using sound-attenuating earphones. Study sample: Seventeen patients with previously or currently subjectively fluctuating hearing loss. Five patients received of treatment for their conditions during the measurement period. Results: Measurement periods ranged from 6 to 60 days. Varying degrees of compliance were seen, some patients measuring less than 50% of the days, others measuring every day. Based on their long-term measurements the patients were classified into three groups: patients with stable recordings, with fluctuating low-frequency hearing loss, or with fluctuating high-frequency hearing loss. In the patients with stable recordings, significant test–retest differences were seen below 10 dB at frequencies 0.125–8 kHz. Conclusions: Home audiometry with Békésy’s technique can be used to evaluate disease activity and to monitor hearing results after therapy.
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| 18. |
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| 19. |
- Grenner, Jan, et al.
(author)
-
Noise-induced threshold elevation as a function of peak sound pressure level
- 1990
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In: Hearing Research. - 0378-5955. ; 46:1-2, s. 161-169
-
Journal article (peer-reviewed)abstract
- Thirty-three groups of guinea pigs, consisting of five animals in each group, were exposed to a simulated impact noise with peak levels ranging between 119.5 and 134.5 dB SPL. By varying the repetition rate, different equivalent levels could be set at each peak level. The equivalent levels ranged from 96 to 117 dB SPL, and the exposure duration was 1.5 to 24 hours. The compound action potential thresholds were measured in 1/3-octave steps between 1 and 20 kHz, one month after the exposure. Higher peak levels resulted in a peak-shaped threshold elevation with a maximum around 8 kHz. For constant peak levels, the equal energy theory was supported. For exposures of equal energy but different peak levels, significantly higher threshold elevations resulted after exposure to higher peak levels.
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| 20. |
- Grenner, Jan, et al.
(author)
-
Right-left correlation in guinea pig ears after noise exposure
- 1990
-
In: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 109:1-2, s. 41-48
-
Journal article (peer-reviewed)abstract
- In order to investigate whether experimental material consisting of noise-exposed animals should be regarded as 'ears' or 'animals', a comparison was made between the permanent threshold shifts in the right and left ears in 53 groups of noise-exposed guinea-pigs, with 5 animals in each group. The action potential (N1) thresholds were measured at fourteen frequencies in both ears. In the noise-exposed animals, the threshold elevations were up to 40 dB. The average right-left correlation coefficient within each group was about 0.79, regardless of noise energy. The degree of correlation was significantly greater after impact noise than after continuous noise. As a consequence of the high right-left correlation, the informative value of measuring a second ear in the same animal was, in our experiments, only 11% of that of the first one. No correlation could be found between the degree of skin pigmentation and the threshold elevation.
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