Apparatus and methods for mitigating impairments due to central auditory nervous system binaural phase-time asynchrony
Pathological binaural phase time delay (PBTD) asynchrony is measured at a variety of frequencies and speech stimuli to develop a BPTD profile for a subject. A corrective device ( 600, 1000 ) is designed to apply clinical PBTD to compensate for the subject's pathological BPTD. An electronic device ( 500 ) is used to measure the subject's ability to comprehend words at a variety of relative time delays between ears to estimate the ideal overall relative time delay. The optimal relative phase shift at a variety of frequencies is also measured. An electronic device ( 600 ) may be used to correct the pathological BPTD by delaying sound in different frequency bands differently to the target ear, according to the BPTD profile, or a passive filtered earplug ( 1000 ) may be used to correct smaller amounts of BPTD.
1. An apparatus to compensate for a measured binaural phase time delay profile of an individual comprising:
a sound signal delay element configured to delay sound signals to an ear of the individual according to the binaural phase time delay profile; and
a frequency differing phase shift element configured to apply different phase shifts at different frequencies according to the binaural phase time delay profile, the binaural phase time delay being a synchronization disruption in phase and time of auditory input signals to the individual's ears.
2. The apparatus of claim 1 , wherein the sound signal delay element comprises a passive earplug having ducting which delays propagation of sound relative to air.
3. The apparatus of claim 2 , wherein the ducting is fluid filled.
4. The apparatus of claim 2 , wherein the frequency differing phase shift element comprises at least one acoustical filter element within the ear plug.