Chirp-evoked auditory steady-state responses: Optimal parameters for rapid and objective tests of hearing

• Applicant: Professor Dr. Jesko L. Verhey
• Subject Area: Otolaryngology, Phoniatrics and Audiology
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 326379052

• Final Report Year: 2021

Final Report Abstract

The hearing ability of a patient is commonly characterized by measuring, for a range of stimulus frequencies, the hearing thresholds, i.e., the minimum level at which a stimulus is detected. For non-cooperative patients, such as young children, hearing thresholds can be determined from physiological responses of the auditory system. This project focussed on auditory steady state responses (ASSR) which measure the response to periodic signals by analysing the spectrum of the physiological response. Stimuli that are used in the clinical routine for ASSR measurements are repeated narrow-band chirps. Athough already clinically used, the effect of several parameters influencing the ASSR with this stimulus type are not yet fully understood. Thus, the aim of this project was to shed some light on the effect of several parameters that have the possibility to optimise ASSR measurements. We measured how the ASSR amplitude changes (i) with level, (ii) with the number of simultaneously presented stimuli, (iii) and when one of simultaneously presented stimuli had a higher level. In addition, we investigated the noise floor in the measurement is affected by anesthesia and how stimuli with largely different periodicity can be measured simulateneously in a clinical setup. This latter question was important since the effect of arousal depends on the periodicity of the stimulus. Finally, we tested how a lock-in amplifier may be used to enhance ASSR. The results can provide interesting information for the optimisation of ASSR measurement in the clinical routine.

Publications

• (2018) Simultaneous acquisition of 40- and 80-Hz auditory steady-state responses for a direct comparison of response amplitude, residual noise and signal-to-noise ratio. Eur Arch Otorhinolaryngol
  Mühler R, Petzke A, Verhey JL
  
• (2019) Hörschwellenbestimmungen bei Kindern mittels früher akustisch evozierter Potenziale. HNO
  Knaus V, Mühler R, Verhey JL