Tactile Auditory Sensory Substitution

1. Tactile Auditory Sensory Substitution 7 Prototype Costs 5 6 Proposed Design Previous Work 2 Problem Statement 8 Design and develop an auditory substitution device that through the use of vibrotactile stimulation can substitute for regional frequency hearing loss, with an emphasis on clinical testing. Testing 3 Background 2.3 kHz Jimmy Fong , Jack Page, Becky Jones, Ryan Thome, and Matt Valaskey Client: Veronica H. Heide, Au.D. Advisor: Mitchell E. Tyler 1 Handheld Device Abstract • Prototype will be used for testing purposes only • High mechanoreceptor concentration in fingertips • Allows for easier discrimination between tactors • Increases simplicity of device for client demographic • Less invasive for testing purposes • Non-real-time using prefiltered recorded sound files • Circuit drove four motors behind the ear High frequency hearing loss is a problem common among people of all age groups. People who suffer from this type of hearing loss often lose the ability to hear certain consonant sounds. The goal of this project is to replace the missing high frequency information using sensory substitution. DSP: $415.00 Circuit Components: $5.00 Motors: $15.96 Housing: $5.00 Microphone: $15.00 Total: $455.96 By Team TASS, Spring ‘07 Device Layout IRB Approval: IRB Clinical Subjects Testing application submitted • California Consonant Test (CCT) • Consists of a 100 multiple-choice test • Tests using high-frequency words • Established grading system to evaluate performance • Sample question: • Target audio: “Chill” • Choices: A) Kill B) Pill C) Chill D) Till • Normal hearing = 50 – 20,000 Hz • High-frequency hearing loss = Above 1,000 Hz • Categorized as sensorineural hearing loss • Loss of ability to hear certain high frequency consonant sounds such as S, Sh, or F. • Pairs of words that can • be distinguished with device • Sixty versus Fifty • MuchversusSuch • Chill versus Till Digital Signal Processor • Interfaces LabVIEW 8.2 program with TI DSP Starter Kit • DSP Starter Kit allows for acoustic analog input and provides four digital outputs • Power supplied from wall outlet transformed to 5 Volt, 3 Amp DC • LabVIEW program performs real-time filtering and adaptive thresholding • Custom daughterboard amplifies current and provides physical connection to handheld motor device 9 Future Work • Next semester: • Improve ergonomics of handheld device • Test efficacy of device on subjects with normal hearing and high frequency hearing loss • Analyze and report testing data and results • Commercial Prototyping: • Miniaturization of DSP and circuit • Re-evaluate vibrotactile motor placement • Battery powered (stand-alone device) Filter Bands 7.6 kHz Channel to Frequency Breakdown: • 1: 1.6-2.0 kHz – p, i, k • 2: 2.0-3.0 kHz – ch, sh 3: 3.0-3.5 kHz – ch, t • 4: 4.5-8.0 kHz – s, th, f 4 10 Design Specifications Acknowledgements and References Power spectral density analysis of speech segments • Help the user in everyday communication situations • Use tactile stimulation • Self contained • Portable • Discrete and aesthetically acceptable We would like to thank all of those who contributed to this project’s progress, especially our advisor and clients, Prof. Mark Allie, Prof. Michael Morrow, Amit Nimunkar, and DongGee Hong Krames Communications. (1995). Hearing Aids. [Brochure]. San Bruno, CA. Kanyo, M. et al. 2005. A Tactile Synthesis Method Using Multiple Frequency Vibrations for Representing Virtual Touch. IEEE/RSJ. p 1121 – 1127. Vibrotactile Motors • 12mm diameter, 3.4mm thick • 1G vibration • 12,000 RPM • Requires <3V and <50mA Vibrating Motor