TACTILE AID FOR THE DEAF

THE AIM OF THE PROPOSED RESEARCH IS TO DEVELOP A DIGITAL TACTILE VOCODER SIGNIFICANTLY IMPROVED OVER EXISTING COMMERCIALLY AVAILABLE DEVICES. CURRENT VOCODERS HAVE HAD A SIGNIFICANT IMPACT ON THE DEVELOPMENT OF LANGUAGE AND SPEECH SKILLS IN PROFOUNDLY DEAF CHILDREN. THEIR IMPACT HAS BEEN LIMITED HOWEVER, IN THAT THEY HAVE SEVERAL SIGNIFICANT BUT REMEDIABLE PROBLEMS. THESE PROBLEMS INCLUDE (1) THE FAILURE TO TRANSMIT ADEQUATELY INFORMATION ABOUT VOICE FUNDAMENTAL FREQUENCY AND (2) THE FAILURE TO TRANSMIT RAPIDLY CHANGING BRIEF COMPONENTS OF THE SPEECH SIGNAL, NAMELY FORMANT TRANSITIONS. BOTH VOICE FUNDAMENTAL FREQUENCY AND FORMANT TRANSITIONS CARRY A SIGNIFICANT PORTION OF THE CODE NEEDED FOR SPEECH COMMUNICATION. THE PROPOSED RESEARCH SEEKS TO TEST THE FEASIBILITY OF NEW APPROACHES TO THE PROBLEMS OF SPEECH TRANSMISSION OF FUNDAMENTAL FREQUENCY AND FORMANT TRANSITIONS BY (1) TESTING SIGNAL PROCESSING STRATEGIES THAT CAN EFFICIENTLY AND ACCURATELY EXTRACT BOTH FORMANT AND FUNDAMENTAL FREQUENCY INFORMATION IN REAL TIME AND (2) DESIGNING A NEW CLASS OF STIMULATORS CAPABLE OF TRANSMITTING FUNDAMENTAL FREQUENCY AS THE FREQUENCY OF VIBRATION OF STIMULATION. THE CHARACTERISTICS OF THE VIBRATORS AND SIGNAL PROCESSING STRATEGIES WILL BE EVALUATED USING PSYCHOPHYSICAL METHODS WITH REAL SPEECH STIMULI.