Frequency-multiplexed speech-sound stimuli for hierarchical neural characterization of speech processing

Abstract

A system and method for generating frequency-multiplexed synthetic sound-speech stimuli and for detecting and analyzing electrical brain activity of a subject in response to the stimuli. Frequency-multiplexing of speech copora and synthetic sounds helps the composite sound to blend into a single auditory object. The synthetic sounds are temporally aligned with the utterances of the speech corpus. Frequency multiplexing may include splitting the frequency axis into alternating bands of speech and synthetic sound to minimize the disruptive interaction between the speech and synthetic sounds along the basilar membrane and in their neural representations. The generated stimuli can be used with both traditional and advanced techniques to analyze electrical brain activity and provides a rapid, synoptic view into the functional health of the early auditory system, including how speech is processed at different levels and how these levels interact.

What is claimed is: 
     
         1 . A system for detecting and analyzing electrical brain activity, comprising:
 at least one detector;   a computer processor; and   a non-transitory computer-readable medium storing instructions executable by the computer processor;   wherein said instructions, when executed by the computer processor, perform steps comprising:
 presenting one or more frequency-multiplexed synthetic stimuli to a test subject, wherein the stimuli comprise at least one speech corpus that is multiplexed with a train of synthetic signals; and 
 detecting, with the at least one detector, an electrophysiological response from the test subject to the presented stimuli. 
   
     
     
         2 . The system of  claim 1 , wherein said instructions, when executed by the computer processor, further perform the following step:
 evaluating the detected electrophysiological response of the test subject.   
     
     
         3 . The system as of  claim 1 , wherein the detector is selected from the group of detectors consisting of electroencephalography EEG, magnetoencephalography MEG, electrocorticography ECoG, and cochlear implant telemetry. 
     
     
         4 . The system of  claim 1 , wherein said one or more frequency-multiplexed synthetic stimuli are selected from a library of stimuli. 
     
     
         5 . The system of  claim 1 , wherein the speech corpus is a clinical speech corpus selected from the group consisting of HINT, QuickSIN, Synthetic Sentence Identification test and the Harvard/IEEE (1969) speech corpus. 
     
     
         6 . The system of  claim 1 , wherein the train of synthetic signals comprises a non-speech sound selected from the group consisting of chirps, clicks, tones, tone-complexes, and amplitude-modulated noise bursts. 
     
     
         7 . The system of  claim 1 , wherein said instructions, when executed by the computer processor, further perform the following step:
 generating the one or more frequency-multiplexed synthetic stimuli with steps comprising:
 providing at least one speech corpus having a plurality of utterances; 
 providing a train of synthetic signals; and 
 multiplexing the train of synthetic signals with the speech corpus to generate the stimuli; wherein the synthetic signals are temporally aligned with the utterances of the speech corpus. 
   
     
     
         8 . The system of  claim 7 , wherein generating the one or more frequency-multiplexed synthetic stimuli further comprises:
 flattening speech corpus pitch to an approximately constant value; and   temporally shifting glottal pulses of the speech corpus.   
     
     
         9 . The system of  claim 7 , wherein generating the one or more frequency-multiplexed synthetic stimuli further comprises:
 splitting a frequency axis into alternating bands of speech and synthetic signal; wherein disruptive interactions between the speech and synthetic signals along the basilar membrane and in their neural representations are minimized.   
     
     
         10 . The system of  claim 1 , wherein the at least one speech corpus comprises an electrical speech signal, and wherein the one or more frequency-multiplexed synthetic stimuli comprises an electrical transmission. 
     
     
         11 . A system for detecting and analyzing electrical brain activity, comprising:
 at least one detector;   a computer processor; and   a non-transitory computer-readable medium storing instructions executable by the computer processor;   wherein said instructions, when executed by the computer processor, perform steps comprising:
 generating one or more frequency-multiplexed synthetic stimuli with steps comprising:
 providing at least one speech corpus having a plurality of utterances; 
 providing a train of synthetic signals; and 
 multiplexing the train of synthetic signals with the speech corpus to generate the stimuli; wherein the synthetic signals are temporally aligned with the utterances of the speech corpus; 
 
 presenting the one or more frequency-multiplexed synthetic stimuli to a test subject; and 
 detecting, with the at least one detector, an electrophysiological response from the test subject to the presented stimuli. 
   
     
     
         12 . The system of  claim 11 , wherein said instructions, when executed by the computer processor, further perform the following step:
 evaluating the detected electrophysiological response of the test subject.   
     
     
         13 . The system as recited in  claim 11 , wherein the detector is selected from the group of detectors consisting of electroencephalography EEG, magnetoencephalography MEG, electrocorticography ECoG, and cochlear implant telemetry. 
     
     
         14 . The system as recited in  claim 11 , wherein the speech corpus is a clinical speech corpus selected from the group consisting of HINT, QuickSIN, Synthetic Sentence Identification test and the Harvard/IEEE (1969) speech corpus. 
     
     
         15 . The system of  claim 11 , wherein the train of synthetic signals comprises a non-speech sound selected from the group consisting of chirps, clicks, tones, tone-complexes, and amplitude-modulated noise bursts. 
     
     
         16 . The system of  claim 11 , wherein generating the one or more frequency-multiplexed synthetic stimuli further comprises:
 flattening speech corpus pitch to an approximately constant value; and   temporally shifting glottal pulses of the speech corpus.   
     
     
         17 . The system of  claim 11 , wherein generating the one or more frequency-multiplexed synthetic stimuli further comprises:
 splitting a frequency axis into alternating bands of speech and synthetic signal; wherein disruptive interactions between the speech and synthetic signals along the basilar membrane and in their neural representations are minimized.   
     
     
         18 . The system of  claim 11 , wherein the at least one speech corpus comprises an electrical speech signal, and wherein the one or more frequency-multiplexed synthetic stimuli comprises an electrical transmission. 
     
     
         19 . A system for detecting and analyzing electrical brain activity, comprising:
 at least one detector;   a computer processor; and   a non-transitory computer-readable medium storing instructions executable by the computer processor;   wherein said instructions, when executed by the computer processor, perform steps comprising:
 presenting one or more frequency-multiplexed synthetic sound-speech stimuli to a test subject, wherein the stimuli comprise at least one speech corpus that is multiplexed with a train of synthetic sounds such that the stimuli comprise a frequency axis split into two or more bands of speech and synthetic sound; and 
 detecting, with the at least one detector, an electrophysiological response from the test subject to the presented stimuli. 
   
     
     
         20 . The system of  claim 19 , wherein said instructions, when executed by the computer processor, further perform the following step:
 generating the one or more frequency-multiplexed synthetic sound-speech stimuli with steps comprising:
 providing at least one speech corpus having a plurality of utterances; 
 providing a train of synthetic sounds; and 
   multiplexing the train of synthetic sounds with the speech corpus to generate the stimuli; wherein the synthetic sounds are temporally aligned with the utterances of the speech corpus.