Speech processing method and apparatus
First Claim
1. A signal processing system for converting a speech signal into a data signal for controlling a means for stimulating of a hearing prosthesis for an individual patient, the prosthesis being of the type including an implanted electrode array adapted to stimulate the auditory nerve fibers of a patient by the application of electrical currents to selected electrodes in the array, said processing system comprisingmeans for receiving a speech signal and for generating an electrical input signal having a plurality of components corresponding to a plurality of formant components of the received speech signal,first means for generating from said input signal electrical signals representative of at least one of the amplitude and frequency of the fundamental voicing component FO of said speech signal,second means for generating from said input signal electrical signals representative of at least one of the amplitudes or frequencies of a plurality of formants of said speech signal,programmable means for producing instruction signals for controlling the application of sets of electrical signals selected from said signals generated by said first and second means to selected groups of electrodes in said array with selectable delays between the stimulation of each electrode in each of said groups, said programmable means includingmeans for storing data representative of a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency based on psychophysical testing of the patient and data defining a predetermined relationship between another formant frequency and the delay between stimulation of electrodes in each group,said programmable means further including means for producing instruction signals for determining the level of stimulation of each selected group of electrodes as a function of the amplitude of said formants of said speech signal, andstorage means for generating and storing stimulus signals corresponding to said instructions and for releasing said signals, separated in time by said selectable delays, to said means for stimulating the selected electrodes.
1 Assignment
0 Petitions
Accused Products
Abstract
Signal processing system for converting a speech signal into a data signal for controlling a hearing prosthesis having an implanted electrode array adapted to stimulate the auditory nerve fibers of a patient by the application of electrical currents to selected electrodes in the array. The system generates an input signal current corresponding to a received speech signal. The amplitude and frequency of the fundamental voicing component of the speech signal is approximated as are the amplitude and frequency of at least one formant of the speech signal. A programmable microprocessor produces instructions which cause the application of electrical currents to selected groups of electrodes in the array with or without delays between the stimulation of each electrode in the groups. The microprocessor is programmable with data defining a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency and with data defining a predetermined relationship between another formant frequency and the delay between stimulation of each electrode in each said group based on psychophysical testing of the patient. Selection of electrodes based on the estimated frequency of the formants produces the desired percepts in the auditory-like sensations generated in the patient. The microprocessor is further programmable to produce data which determines the level of stimulation of each selected group of electrodes and determines the delay between stimulation of electrodes in each group dependent on the estimated amplitude of formants of the speech signal as well as on predetermined data relating to the sensitivity of each electrode implanted in the patient.
-
Citations
11 Claims
-
1. A signal processing system for converting a speech signal into a data signal for controlling a means for stimulating of a hearing prosthesis for an individual patient, the prosthesis being of the type including an implanted electrode array adapted to stimulate the auditory nerve fibers of a patient by the application of electrical currents to selected electrodes in the array, said processing system comprising
means for receiving a speech signal and for generating an electrical input signal having a plurality of components corresponding to a plurality of formant components of the received speech signal, first means for generating from said input signal electrical signals representative of at least one of the amplitude and frequency of the fundamental voicing component FO of said speech signal, second means for generating from said input signal electrical signals representative of at least one of the amplitudes or frequencies of a plurality of formants of said speech signal, programmable means for producing instruction signals for controlling the application of sets of electrical signals selected from said signals generated by said first and second means to selected groups of electrodes in said array with selectable delays between the stimulation of each electrode in each of said groups, said programmable means including means for storing data representative of a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency based on psychophysical testing of the patient and data defining a predetermined relationship between another formant frequency and the delay between stimulation of electrodes in each group, said programmable means further including means for producing instruction signals for determining the level of stimulation of each selected group of electrodes as a function of the amplitude of said formants of said speech signal, and storage means for generating and storing stimulus signals corresponding to said instructions and for releasing said signals, separated in time by said selectable delays, to said means for stimulating the selected electrodes.
-
5. A method of producing electrical current signals for selective application to electrodes in an array of electrodes implanted in a patient forming a hearing prosthesis in response to a speech signal to thereby stimulate the auditory nerve fibers of a patient comprising
forming an electrical input signal corresponding to the speech signal, producing from the input signal a fundamental signal representative of the voicing frequency of the speech signal, producing from the input signal a first signal representative of the amplitude and frequency characteristics of a first formant of the speech signal, defining a predetermined relationship between each of a plurality of groups of electrodes and a selected frequency band of the formant frequency and storing data representative thereof, producing from the input signal a second signal representative of the amplitude and frequency of a second formant of the speech signal, defining a predetermined relationship between the frequency characteristics of the second signal and the electrode sharpness response determined by psychophysical testing of the patient and storing data representative thereof, selecting electrodes to be stimulated based on the correlation between the frequency of the first and second signals and the electrode response so that stimulation thereof can produce desired percepts in the auditory-like sensations generated in the patient, determining the level of stimulation of each selected group of electrodes as a function of the amplitudes of the formant signals and the loudness the auditory-like sensation generated in the patient, and the delay to be used between stimulation of electrodes in each group as a function of the formant signal frequencies and the sharpness response of each electrode implanted in the patient and storing data representative thereof, and applying current signals at a rate proportional to the voicing frequency to the selected electrode groups in accordance with the stored data and with the defined delay factors between stimulation of individual electrodes in each group.
-
6. A signal processing system for converting a speech signal into a data signal for controlling a means for stimulating of a hearing prosthesis for an individual patient, the prosthesis being of the type including an implanted electrode array adapted to stimulate the auditory nerve fibers of a patient by the application of electrical currents to selected electrodes in the array, said processing system comprising
means for receiving a speech signal and for generating an electrical input signal having a plurality of formant components corresponding to the formant components of the received speech signal, first means for generating from said input signal electrical signals representative of at least one of the amplitude and frequency of the fundamental voicing component FO of said speech signal, second means for generating from said input signal electrical signals representative of at least one of the amplitudes and frequencies of a plurality of formants of said speech signal, programmable means for producing instruction signals for controlling the application of sets of electrical signals in a manner determined by said signals generated by said first and second means to selected groups of electrodes in said array with selectable delays between the stimulation of electrodes in each of said groups, said programmable means including means for storing data representative of a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency and data defining a predetermined relationship between another formant frequency and the delay between stimulations of electrodes in each said group based on psychophysical testing of the patient, and selection logic means for selecting the electrodes to be stimulated as a function of the approximated frequency of said formants to produce the desired percepts in the auditory-like sensations generated in the patient, said programmable means further including means for producing and supplying to said means for stimulating instruction signals for determining the level of stimulation of each selected group of electrodes as a function of the amplitude of said formants of said speech signal and determining the delay between the stimulation of individual electrodes in each said group as a function of the formant signal frequencies.
-
7. A signal processing system for converting a speech signal into a data signal for controlling a means for stimulating of a hearing prosthesis for an individual patient, the prosthesis being of the type including an implanted electrode array adapted to stimulate the auditory nerve fibers of a patient by the application of sets of electrical currents to selected electrodes in the array, said processing system comprising
means for receiving a speech signal and for generating an electrical input corresponding to the received speech signal; -
means for generating from said input signal electrical signals characterizing acoustic features of the speech signal; programmable means for obtaining from said electrical signals and storing data representative of a relationship between said acoustic features as represented by said signals and sets of electric current stimuli to be applied to said electrode array; and means for producing instruction signals for controlling the application of said sets of stimuli by said means for stimulating wherein a stimulus set comprises at least two current pulse stimuli applied sequentially to at least two electrodes, and wherein said sets of stimuli are applied at a rate derived from the voicing frequency of the speech signal for voiced utterances and at a rate independent of the voicing frequency for unvoiced utterances. - View Dependent Claims (8, 9, 10, 11)
-
Specification