This study aims to develop an improved neonatal hearing screening device that will incorporate novel testing procedures combining simultaneous air and bone conduction testing so that mild hearing losses (<35 dB nHL) are better and consistently detected. The proposed device will address the current need for a more sensitive hearing screening tool by stimulating at lower levels using a Stimulus Intensity-Ramping technique and providing bone conduction stimulation in order to differentiate between sensorineural and conductive components. Intelligent Hearing Systems previously developed the Stimulus Intensity-Ramping technique for quickly determining frequency specific AEP hearing thresholds. During Phase I, this technique was expanded and combined with simultaneous air and bone conduction testing using various approaches, including: A) Dual-Rate Air-Bone stimulation and B) Overlapping Air-Bone Intensity- Ramping Stimulation and C) Interweaving Air-Bone stimulation. Experiments conducted during Phase I demonstrated the feasibility of the proposed techniques using 10 adult subjects with normal and simulated conductive hearing losses. In addition, testing was also conducted on 10 NICU newborns in order to demonstrate that the proposed technique could be applied to the target population. During Phase II, work will continue to further develop the techniques implemented during Phase I and a more comprehensive clinical study will be conducted using 60 adults, with normal and simulated conductive hearing loss (20), actual conductive hearing loss (20) and sensorineural hearing loss (20). Infants will include 100 newborns from the NICU with infants failing routine hearing screening and those marginally passing screening recruited with results compared to infants who pass newborn screening. The results obtained from the experimental protocol will be compared to a comprehensive diagnostic auditory battery including frequency specific AEP testing. Development of a new generation of a high fidelity bone-conduction stereo stimulator more suitable for testing newborns will also be conducted. The newly developed simultaneous air and bone conduction based hearing screening techniques will allow for better identification and management of hearing loss cases and implementation of more efficient rescreening policies.
Newborn hearing screening is an important assessment tool in the early identification of infants hearing loss. The implementation of the proposed automated dual air and bone stimulation and analysis techniques is expected to greatly improve the reliability and validity of hearing screening. As such, the proposed work will greatly impact publi health by developing better newborn hearing screening systems.