Speech Intelligibility In Conditions Research Articles

Rehabilitation of patients after ear surgery: prospects of auditory and vestibular training in non­invasive neuromodulation

The objective of the research is to evaluate the efficacy of rehabilitation in 73 patients with hearing and vestibulation impairment after ear surgery. Rehabilitation had the form of a set of auditory and vestibular training in conditions of non­invasive neuromodulation. Vestibular training had the form of an exercise on equilibrium control with the eyes closed performed with the help of Brain Port device during a week after surgery. Audial training was a 10-days acoustic stimulation on the expiry of 1 month after surgery. In both cases non­invasive neuromodulation was provided by electrotactile stimulation of tongue using Brain Port device. The data of tone threshold audiometry, speech intelligibility in conditions of speech interference, computerized posturography and gate examination were evaluated. The results confirm effectiveness of the used rehabilitation activities for speech intelligibility and gait improvement in majority of the patients.

The role of high-frequency envelope fluctuations for speech masking release

The speech-based envelope power spectrum model (sEPSM; Jo/rgensen and Dau, 2011; Jo/rgensen et al., 2013) was shown to successfully predict speech intelligibility in conditions with stationary and fluctuating interferers, reverberation, and spectral subtraction. The key element in the model was the multi-resolution estimation of the signal-to-noise ratio in the envelope domain (SNRenv) at the output of a modulation filterbank. The simulations suggested that mainly modulation filters centered in the range from 1-8 Hz contribute to speech intelligibility in the case of stationary maskers whereas modulation filters tuned to frequencies above 16 Hz might be important in the case of fluctuating maskers. In the present study, the role of high-frequency envelope fluctuations for speech masking release was further investigated in conditions of speech-on-speech Simulations were compared to various measured data from normal-hearing listeners (Festen and Plomp, 1990; Christiansen et al., 2013). The results support the hypothesis that high-frequency envelope fluctuations (>30 Hz) are essential for speech intelligibility in conditions with speech interferers. While the sEPSM reflects effects of energetic and modulation masking in speech intelligibility, the remaining unexplored effect in some conditions may be attributed to, and defined as, informational masking.

Speech intelligibility in real and virtual adverse auditory environments

The purpose of this investigation was to examine the effects of real and virtual adverse conditions on speech intelligibility. The experiment was designed to examine the effect of presentation method on speech intelligibility in conditions of noise and reverberation as signal-to-noise ratio was systematically varied. Additionally, this investigation evaluated the influence of talker gender on speech intelligibility in anechoic and reverberant environments as a function of signal-to-noise ratio and presentation method. Speech intelligibility scores were obtained from 21 normal hearing subjects using a nonsense syllable test. The syllables were recorded in three environments (diotic anechoic, virtual anechoic, and virtual reverberant) with three signal-to-noise ratios (0, 5, 9 dB) using two simultaneous masking sources. The findings indicate that (a) traditional diotic presentation of these stimuli degrades speech intelligibility compared to virtual presentation and may not accurately represent real-world performance; (b) the signal-to-noise ratios did not influence performance trends between presentation modes, as intelligibility improved with increasing SNR; (c) reverberation decreased intelligibility although the effects were not as dramatic as expected; and (d) using these stimuli, the female talker tokens were more easily identified than male talkers in a virtual presentation, but not generally for diotic presentation. [Work supported by NICDC and U.S. Army.]