A micro-drive hearing aid: a novel non-invasive hearing prosthesis actuator

Abstract

The direct hearing device (DHD) is a new auditory prosthesis that combines conventional hearing aid and middle ear implant technologies into a single device. The DHD is located deep in the ear canal and recreates sounds with mechanical movements of the tympanic membrane. A critical component of the DHD is the microactuator, which must be capable of moving the tympanic membrane at frequencies and magnitudes appropriate for normal hearing, with little distortion. The DHD actuator reported here utilized a voice coil actuator design and was 3.7 mm in diameter. The device has a smoothly varying frequency response and produces a precisely controllable force. The total harmonic distortion between 425 Hz and 10 kHz is below 0.5% and acoustic noise generation is minimal. The device was tested as a tympanic membrane driver on cadaveric temporal bones where the device was coupled to the umbo of the tympanic membrane. The DHD successfully recreated ossicular chain movements across the frequencies of human hearing while demonstrating controllable magnitude. Moreover, the micro-actuator was validated in a short-term human clinical performance study where sound matching and complex audio waveforms were evaluated by a healthy subject.

Concept and Evaluation of a New Piezoelectric Transducer for an Implantable Middle Ear Hearing Device

“…A typical hearing aid’s THD lies between 2% and 3% [ 36 ]. Considering implantable middle ear hearing device is a kind of implantable hearing aid, many researchers also utilized the THD to assess their implantable middle ear hearing device’s sound quality [ 7 , 22 , 26 ]. The THD of our transducer is displayed in Figure 7 , which has a maximum value of 0.71% at 1.5 kHz.…”

“…Low nonlinear distortions play a significant role in producing high-fidelity sound, especially for speech and music perception [ 25 ]. The total harmonic distortion (THD) is one of the common measures of nonlinear distortion and was utilized by many researchers to assess the implantable middle ear hearing devices’ distortions [ 7 , 22 , 26 ]. To derive the THD of this piezoelectric transducer, we used the function generator (Tektronix AFG3000) to apply a set of single-frequency voltages to the transducer, respectively.…”

Attenuating the ear canal feedback pressure of a laser-driven hearing aid

“…It has been hypothesized that better sound-transmission efficiency might be possible through stimulation of the short process of the malleus rather than the umbo (Paulick et al, 2014). To test this hypothesis, the MSG and EPO are calculated for a force applied at the short process of the malleus.…”