Audiological Results with Baha^® in Conductive and Mixed Hearing Loss

Abstract

The level of improvement in the audiological results of Baha(®) users mainly depends on the patient's preoperative hearing thresholds and the type of Baha sound processor used. This investigation shows correlations between the preoperative hearing threshold and postoperative aided thresholds and audiological results in speech understanding in quiet of 84 Baha users with unilateral conductive hearing loss, bilateral conductive hearing loss and bilateral mixed hearing loss. Secondly, speech understanding in noise of 26 Baha users with different Baha sound processors (Compact, Divino, and BP100) is investigated. Linear regression between aided sound field thresholds and bone conduction (BC) thresholds of the better ear shows highest correlation coefficients and the steepest slope. Differences between better BC thresholds and aided sound field thresholds are smallest for mid-frequencies (1 and 2 kHz) and become larger at 0.5 and 4 kHz. For Baha users, the gain in speech recognition in quiet can be expected to lie in the order of magnitude of the gain in their hearing threshold. Compared to its predecessor sound processors Baha(®) Compact and Baha(®) Divino, Baha(®) BP100 improves speech understanding in noise significantly by +0.9 to +4.6 dB signal-to-noise ratio, depending on the setting and the use of directional microphone. For Baha users with unilateral and bilateral conductive hearing loss and bilateral mixed hearing loss, audiological results in aided sound field thresholds can be estimated with the better BC hearing threshold. The benefit in speech understanding in quiet can be expected to be similar to the gain in their sound field hearing threshold. The most recent technology of Baha sound processor improves speech understanding in noise by an order of magnitude that is well perceived by users and which can be very useful in everyday life.

Better Understanding of Direct Bone-Conduction Measurement: Comparison with Frequency-Specific Bone-Conduction Tones and Brainstem Responses

“…Hodgetts, et al [16] explained this as inherent low frequency noise of the BAHA because the inherent noise masks the aided thresholds at 250 and 500 Hz. This was also supported by Pfiffner, et al [17] in that physical characteristics of the sound processor provided a maximal output force at approximately 1 kHz. If this statement extends to our correlation results, it would be a strong finding with a significantly positive correlation between PTA and BC direct and between PTA and ABR at 1 kHz.…”

Experimental investigation of promontory motion and intracranial pressure following bone conduction: Stimulation site and coupling type dependence

“…In clinical evaluations of hearing, BC testing with stimulation by tuning forks or by pure-tone audiometry is an important diagnostic method to differentiate between a conductive, sensorineural and mixed hearing loss (Hulecki and Small, 2011). Further, bone conduction hearing aid (BCHA) treatment has become the standard of care for patients suffering from conductive or mixed hearing losses who cannot wear conventional hearing aids, and for patients with single-sided deafness (SSD) (Pfiffner et al, 2011). In patients with SSD, sound needs to travel from the site of stimulation to the contralateral cochlea.…”

Performance evaluation of a novel piezoelectric subcutaneous bone conduction device

“…Since some of the possible BC pathways are independent of the state of the middle ear, BC can be used as an alternative to AC in case of disruption of the sound transmission function of the middle ear. Clinically this is applied in patients with single-sided deafness, or with a conductive hearing loss, who cannot benefit from a conventional hearing aid but can benefit from BC stimulation via a bone conduction hearing aid (BCHA) (Pfiffner et al 2011). An optimal coupling of the BCHA aims at providing a sufficiently efficient transfer of the sound energy from the device's actuator, through the head structures, and into the cochlea.…”