Developing an educational electro-mechanical model of the middle ear and impulse noise reduction algorithm for cochlear implant users

In the United States, approximately 15% of adults (37.5M) age 18 and over report some trouble hearing[1,2], 1 in 8 people (13%, or 30M) 12 years or older have hearing loss in both ears[2,3], and approximately 3 out of 1000 children are born with hearing loss[2,4]. Educating the public, especially K-12 students, on the dangers of hearing loss is important. The ability to develop both a physical model of the middle ear along with signal processing simulation of effective impulsive sound suppression for hearing aids/cochlear implants will help provide a useful, hands-on experience for student education. Today, a functioning model of the bones of the middle ear exhibiting movement, forces, and sound conduction that highlight the importance of the ear's natural safety mechanism does not exist. This paper discusses the design of a standalone, interactive, and educational electro-mechanical model that exhibits the motion of the middle ear bones which include: (i) anatomical 3-bone configuration, (ii) fluid environment in the cochlea, and (iii) electrode stimulation to the auditory nerve cortex. This model has been assessed and approved by STEM/SEEC-UTDallas. To highlight the impact of noise protection on hearing, a complementary offline signal processing implementation is included to reduce the negative effects of impulsive-like sounds for cochlear implant users. An adaptable, mathematical relationship defines impulsive like sound conditions and reduces sound energy stimulated by the electrodes without reducing quality/intelligibility in the frequency ranges associated with speech. This algorithm was validated using a paired preference test, a quality test, and an intelligibility test to which the algorithm increased quality of sound by +18%.