Continuous fast tracking of auditory threshold during middle ear surgery using the auditory steady state response...

Area of Science:

• Neuroscience
• Audiology
• Surgical Technology

Background:

• Middle ear surgery carries a risk of iatrogenic hearing loss.
• Continuous monitoring of cochlear sensitivity during surgery is crucial for prevention.
• Auditory brainstem response (ABR) offers an indirect measure of hearing function.

Purpose of the Study:

• To develop and validate a system for real-time tracking of auditory thresholds during middle ear surgery.
• To utilize auditory brainstem response (ABR) for continuous intraoperative cochlear sensitivity assessment.
• To provide surgeons with timely feedback to mitigate the risk of hearing loss.

Main Methods:

• Improved signal-to-noise ratio of ABR measurements using optimized electrodes, bone conductors, and bio-amplifiers.
• Utilized repetitive bone-conducted chirps and contralateral ear masking for precise ABR acquisition.
• Implemented custom software for automatic adjustment of chirp intensity to maintain a target auditory steady-state response (ASSR) amplitude, defining the ASSR threshold.

Main Results:

• The system enabled continuous, rapid tracking of hearing thresholds throughout middle ear surgery in anesthetized patients.
• The intraoperative ASSR threshold closely approximated pre-operative psychoacoustic thresholds (within 10 dB).
• The system's tracking speed is effective, though potentially limited by operating room acoustic noise.

Conclusions:

• The developed system offers a rapid and sensitive method for monitoring cochlear sensitivity during middle ear procedures.
• This technology has the potential to aid surgeons in identifying and avoiding surgical manipulations that could lead to hearing damage.
• Real-time ABR monitoring can significantly enhance surgical safety and improve patient outcomes by preventing iatrogenic hearing loss.