Perception of multiple electrode stimulus patterns: implications for design of an electrotactile speech processor

Area of Science:

• Neuroscience
• Biomedical Engineering
• Speech Processing

Background:

• Electrotactile stimulation is a potential method for conveying speech information to individuals with hearing impairments.
• Current speech processors often use single-electrode stimulation, limiting the amount of information that can be transmitted.

Purpose of the Study:

• To evaluate the feasibility of using multiple-electrode stimulus patterns to enhance speech information transmission via an electrotactile speech processor.
• To assess the impact of different electrode configurations (single, paired, triplets, and combinations) on speech perception and information transmission.

Main Methods:

• Nine adult subjects participated in the study.
• Subjects were presented with various electrotactile stimulus patterns generated by single electrodes, pairs, and triplets.
• Absolute identification scores and information transmission (in bits) were measured for each stimulus pattern.
• Two stimulus sets using combinations of paired and single electrodes were evaluated for their effectiveness in conveying consonant voicing information.

Main Results:

• Absolute identification scores decreased significantly with the use of electrode pairs and triplets compared to single electrodes.
• Information transmission scores did not significantly increase with paired or triplet electrode stimuli.
• Stimuli combining single and paired electrodes showed higher identification scores and increased information transmission.
• The evaluated stimulus sets effectively conveyed simulated consonant voicing information with high accuracy.

Conclusions:

• Simple multi-electrode patterns (pairs, triplets) offer limited improvement over single-electrode electrotactile stimulation for speech processing.
• Combinations of single and paired electrodes show promise for enhancing speech information transmission in electrotactile devices.
• Further research into optimized multi-electrode spatial patterns is warranted for improved tactile speech feedback systems.