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Improving the Accuracy of Baha® Fittings through Measures of Direct Bone Conduction.

Flynn MC, Hillbratt M - Clin Exp Otorhinolaryngol (2012)

Bottom Line: In subjects with SSD, BC Direct results were poorer than contra-lateral bone conduction thresholds, most likely due to transcranial attenuation.The comparison of preferred amplification, based on direct bone conduction or bone conduction audiometry, found higher agreement for fittings based on direct bone conduction measurements.The result for the clinician is that a fitting can take place with less fine-tuning and a greater understanding of the variability of bone conducted sound transmission.

View Article: PubMed Central - PubMed

Affiliation: Cochlear Bone Anchored Solutions, Gothenburg, Sweden.

ABSTRACT

Objectives: Variability in Baha® sound processor fittings may arise from the nature of the implant-to-bone transmission as well as transcranial attenuation for patients with single-sided sensorineural deafness (SSD). One method of improving the predictability of Baha fittings is to measure the individual patient's actual bone conduction thresholds, thereby removing the influences of skin thickness and/or the implant location site.

Methods: Twenty adult wearers of the Baha bone conduction implant system participated in the study. Direct bone conduction thresholds were obtained through the BC Direct function of the Baha Fitting Software combined with the Cochlear Baha BP100 sound processor. For comparison, the masked and unmasked bone conduction responses of the patients were collected through standard audiometric testing techniques. Test-retest reliability measurement was performed for all participants. Data for each frequency and frequency range were analyzed separately.

Results: The results confirm the improved transmission of sound through the implant rather than transcutaneously through the skin. On average, the BC Direct thresholds were closer to the patient's unmasked thresholds than the masked values. In subjects with SSD, BC Direct results were poorer than contra-lateral bone conduction thresholds, most likely due to transcranial attenuation. The test-retest reliability for the BC Direct measurements was within +/-5 dB. The comparison of preferred amplification, based on direct bone conduction or bone conduction audiometry, found higher agreement for fittings based on direct bone conduction measurements.

Conclusion: While the transfer function between the implant and the skin can be predicted on average, there are a number of patients for whom measurement is essential to determine the required amplification. These were patients with: 1) SSD, 2) asymmetrical hearing loss, 3) unusual implant location or skull formation, and 4) users of Testband or Softband. The result for the clinician is that a fitting can take place with less fine-tuning and a greater understanding of the variability of bone conducted sound transmission.

No MeSH data available.


Related in: MedlinePlus

Schematic of the BC Direct function enabling measurement of responses by bone conduction in a Baha.
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Figure 1: Schematic of the BC Direct function enabling measurement of responses by bone conduction in a Baha.

Mentions: The test device used was the Cochlear Baha BP100 (Cochlear Bone Anchored Solutions AB, Gothenburg, Sweden) sound processor in combination with the Cochlear Baha Fitting Software ver. 1.0. The combination allows the use of a software feature called BC Direct to measure direct bone conduction. The patient's responses to the vibratory signals by the Baha sound processor are obtained (Fig. 1). The Fitting Software allows the frequency (Hz) and level (dB HL) of those sounds to be controlled.


Improving the Accuracy of Baha® Fittings through Measures of Direct Bone Conduction.

Flynn MC, Hillbratt M - Clin Exp Otorhinolaryngol (2012)

Schematic of the BC Direct function enabling measurement of responses by bone conduction in a Baha.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369981&req=5

Figure 1: Schematic of the BC Direct function enabling measurement of responses by bone conduction in a Baha.
Mentions: The test device used was the Cochlear Baha BP100 (Cochlear Bone Anchored Solutions AB, Gothenburg, Sweden) sound processor in combination with the Cochlear Baha Fitting Software ver. 1.0. The combination allows the use of a software feature called BC Direct to measure direct bone conduction. The patient's responses to the vibratory signals by the Baha sound processor are obtained (Fig. 1). The Fitting Software allows the frequency (Hz) and level (dB HL) of those sounds to be controlled.

Bottom Line: In subjects with SSD, BC Direct results were poorer than contra-lateral bone conduction thresholds, most likely due to transcranial attenuation.The comparison of preferred amplification, based on direct bone conduction or bone conduction audiometry, found higher agreement for fittings based on direct bone conduction measurements.The result for the clinician is that a fitting can take place with less fine-tuning and a greater understanding of the variability of bone conducted sound transmission.

View Article: PubMed Central - PubMed

Affiliation: Cochlear Bone Anchored Solutions, Gothenburg, Sweden.

ABSTRACT

Objectives: Variability in Baha® sound processor fittings may arise from the nature of the implant-to-bone transmission as well as transcranial attenuation for patients with single-sided sensorineural deafness (SSD). One method of improving the predictability of Baha fittings is to measure the individual patient's actual bone conduction thresholds, thereby removing the influences of skin thickness and/or the implant location site.

Methods: Twenty adult wearers of the Baha bone conduction implant system participated in the study. Direct bone conduction thresholds were obtained through the BC Direct function of the Baha Fitting Software combined with the Cochlear Baha BP100 sound processor. For comparison, the masked and unmasked bone conduction responses of the patients were collected through standard audiometric testing techniques. Test-retest reliability measurement was performed for all participants. Data for each frequency and frequency range were analyzed separately.

Results: The results confirm the improved transmission of sound through the implant rather than transcutaneously through the skin. On average, the BC Direct thresholds were closer to the patient's unmasked thresholds than the masked values. In subjects with SSD, BC Direct results were poorer than contra-lateral bone conduction thresholds, most likely due to transcranial attenuation. The test-retest reliability for the BC Direct measurements was within +/-5 dB. The comparison of preferred amplification, based on direct bone conduction or bone conduction audiometry, found higher agreement for fittings based on direct bone conduction measurements.

Conclusion: While the transfer function between the implant and the skin can be predicted on average, there are a number of patients for whom measurement is essential to determine the required amplification. These were patients with: 1) SSD, 2) asymmetrical hearing loss, 3) unusual implant location or skull formation, and 4) users of Testband or Softband. The result for the clinician is that a fitting can take place with less fine-tuning and a greater understanding of the variability of bone conducted sound transmission.

No MeSH data available.


Related in: MedlinePlus