A proposed Proof-of-Concept experiment CINCARD - Cochlear Implant Neuro-Controlled Auditory Rehabilitation Device A proposed Proof-of-Concept experiment

Healthy ears implement top-down perception Research on top-down perception demonstrates: That there is a universal rule that top-down electrical activity which modulates receptor behavior improves the perception of sensory input. Top-down perception requires closed-loops: CNS activity > efferent action potentials to receptor organ > modulation of receptor action > modulated afferent action potentials back up to CNS > modulated CNS activity... repeated Healthy ears implement closed-loop perception: CNS auditory system action > MOC > OHCs modulate cochlear functioning > modulated IHC stimulation of afferent paths to CNS > modulated CNS auditory system action...repeated

Hearing Impaired (SNHL) ears cannot implement top-down perception. In healthy ears the OHCs modulate basilar membrane action: hence 'cochlear amplifier', improved frequency 'discrimination', 'virtual tones' & etc. In SNHL impaired ears OHCs die before IHCs become dysfunctional. Without OHCs, CNS control of cochlear function is lost.

How CINCARD restores closed-loop perception A passive CI electrode reads un-elicited compound action potentials from the MOC of the implanted ear. This requires a customized Neural Response Imaging system as an interface. CINCARD combines the action-potential signal wth auditory input (sound). CINCARD feeds the combined/modulated signal to a speaker in the hearing-impaired contralateral ear. The modulated stimuli travels afferent paths to the brain via the (contralateral) hearing-impaired ear. The auditory stimuli are processed (as for a healthy ear) and modulate the stream of compound action potentials descending the MOC. Hence the auditory-loop is closed.

CINCARD implementation of the perceptual closed loop

Experimental Hypothesis Improved speech comprehension in noise. Improved comprehension of complex material. Improved semantic comprehension. Improved comprehension of complex material delivered at healthy hearing speed. Increased MOC efferent action.

Experimental Control Conditions Double blind control is acheived by randomly (under computer control) substituting previously recorded MOC input for the real-time MOC input during testing of speech comprehension.

Implications of hypothesis confirmation Use of CINCARD in cases of profound hearing loss in one ear, with advancing SNHL in the other. Development of hybrid CI combining passive and stimuli-providing electrode systems. Stringent re-evaluation of negative effects of current speech processing algorithms such as WDRC, frequency compression and etc. Preventative implantation of passive cochlear implant systems (CINCARD) to delay or mitigate SNHL. Auditory rehabilitation training for CINCARD recipients.

Required resources Equipment: Subject: Audiologist testing services. Custom tailored interface (adapted NRI system). Off-the-shelf items (sound mixer & etc.) of insignificant cost. Subject: CI recipient using contralateral hearing aid. Motivated - deep understanding of the theory - willing to spend months adapting to CINCARD in natural environment as substitute for current configuration. Audiologist testing services. Institute Review Board approval. Informed consent/non-invasive/totally safe/of great potential benefit.