Electro-Tactile Stimulation Enhances Cochlear Implant Speech Recognition in Noise

Area of Science:

• Audiology
• Neuroscience
• Biomedical Engineering

Background:

• Combined electro-acoustic stimulation (EAS) improves cochlear implant (CI) performance.
• Many CI users lack residual low-frequency acoustic hearing.
• Tactile sensation operates in low frequencies (<500 Hz), similar to acoustic hearing in EAS.

Purpose of the Study:

• To investigate the efficacy of electro-tactile stimulation (ETS) as a method to enhance CI performance.
• To compare speech recognition in noise with CI alone versus bimodal ETS.

Main Methods:

• Ten cochlear implant users participated.
• A tactile aid converted voice fundamental frequency to vibrations on the index finger.
• Speech recognition in noise was tested under two conditions: CI alone and bimodal ETS.

Main Results:

• ETS improved speech reception thresholds by an average of 2.2 dB compared to CI alone.
• Nine out of ten subjects demonstrated a positive ETS effect, ranging from 0.3 to 7.0 dB.
• The magnitude of the ETS benefit was comparable to previously reported EAS benefits.

Conclusions:

• ETS is a viable method for enhancing cochlear implant performance, particularly for individuals with limited residual hearing.
• The comparable results suggest shared neural mechanisms underlying ETS and EAS.
• Complementary auditory and tactile sensory inputs show potential for improving speech perception in CI users and potentially in normal-hearing listeners and machine-based speech recognition.