Phonemes in running speech versus isolation

In the past decade, aided speech evoked cortical auditory evoked potentials (CAEPs) have been proposed for validation of hearing aid fittings. However, unlike in running speech, phonemes presented as stimuli during CAEP testing are preceded by silent intervals of over one second. Researchers at the National Centre for Audiology conducted a study to compare if hearing aid process phonemes similarly in running speech and in CAEP testing. A sample of ten hearing aids was used and overall phoneme level and phoneme onset level of eight phonemes in both contexts were compared at three input levels representing conversational speech levels. Differences of over 3dB between the two contexts were noted in one-fourth of the observations measuring overall all phonemes were higher in the running speech context. These differences varied across hearing aids. The researchers concluded that lower output levels in the isolation context may have implications for calibration and estimation of audibility based on CAEPs. "

Source:Int J Otolaryngol. 2012;2012:518202.Science Daily.

Rose Simpson