Joseph Desloge - Academia.edu (original) (raw)

Papers by Joseph Desloge

The Journal of the Acoustical Society of America, 2017

The masking release (i.e., better speech recognition in fluctuating compared to continuous noise ... more The masking release (i.e., better speech recognition in fluctuating compared to continuous noise backgrounds) observed for normal-hearing (NH) listeners is generally reduced or absent in hearingimpaired (HI) listeners. One explanation for this lies in the effects of reduced audibility: elevated thresholds may prevent HI listeners from taking advantage of signals available to NH listeners during the dips of temporally fluctuating noise where the interference is relatively weak. This hypothesis was addressed through the development of a signal-processing technique designed to increase the audibility of speech during dips in interrupted noise. This technique acts to (i) compare shortterm and long-term estimates of energy, (ii) increase the level of short-term segments whose energy is below the average energy, and (iii) normalize the overall energy of the processed signal to be equivalent to that of the original long-term estimate. Evaluations of this energy-equalizing (EEQ) technique included consonant identification and sentence reception in backgrounds of continuous and regularly interrupted noise. For HI listeners, performance was generally similar for processed and unprocessed signals in continuous noise; however, superior performance for EEQ processing was observed in certain regularly interrupted noise backgrounds.

Trends in Hearing, 2017

The masking release (MR; i.e., better speech recognition in fluctuating compared with continuous ... more The masking release (MR; i.e., better speech recognition in fluctuating compared with continuous noise backgrounds) that is evident for listeners with normal hearing (NH) is generally reduced or absent for listeners with sensorineural hearing impairment (HI). In this study, a real-time signal-processing technique was developed to improve MR in listeners with HI and offer insight into the mechanisms influencing the size of MR. This technique compares short-term and long-term estimates of energy, increases the level of short-term segments whose energy is below the average energy, and normalizes the overall energy of the processed signal to be equivalent to that of the original long-term estimate. This signal-processing algorithm was used to create two types of energy-equalized (EEQ) signals: EEQ1, which operated on the wideband speech plus noise signal, and EEQ4, which operated independently on each of four bands with equal logarithmic width. Consonant identification was tested in backgrounds of continuous and various types of fluctuating speech-shaped Gaussian noise including those with both regularly and irregularly spaced temporal fluctuations. Listeners with HI achieved similar scores for EEQ and the original (unprocessed) stimuli in continuous-noise backgrounds, while superior performance was obtained for the EEQ signals in fluctuating background noises that had regular temporal gaps but not for those with irregularly spaced fluctuations. Thus, in noise backgrounds with regularly spaced temporal fluctuations, the energy-normalized signals led to larger values of MR and higher intelligibility than obtained with unprocessed signals.

The Journal of the Acoustical Society of America, 2017

Lou’s early work in the area of improved signal processing for hearing aids included his research... more Lou’s early work in the area of improved signal processing for hearing aids included his research on compression amplification to combat the effects of loudness recruitment in listeners with sensorineural hearing loss. Working with his doctoral students (including Rich Lippmann, Steve De Gennaro, and Diane Bustamante), Lou made major contributions towards an analytical understanding of the benefits and limitations of compression amplification as a component of hearing aids. Recently, Lou has been involved in work on a new signal-processing scheme which operates to equalize the energy in a speech signal over time. This energy-equalization (EEQ) scheme shares a similar goal with compression amplification in that they both attempt to match the range of speech levels into the reduced dynamic range of a listener with sensorineural loss. Their operation, however, is different: while compression amplification is based on the actual sound-pressure level of the signal, the EEQ scheme operates on relative energy ca...

The Journal of the Acoustical Society of America, 2016

Acoustic speech is marked by time-varying changes in the amplitude envelope that may pose difficu... more Acoustic speech is marked by time-varying changes in the amplitude envelope that may pose difficulties for hearing-impaired listeners. Removal of these variations (e.g., by the Hilbert transform) could improve speech reception for such listeners, particularly in fluctuating interference. Léger, Reed, Desloge, Swaminathan, and Braida [(2015b). J. Acoust. Soc. Am. 138, 389-403] observed that a normalized measure of masking release obtained for hearing-impaired listeners using speech processed to preserve temporal fine-structure (TFS) cues was larger than that for unprocessed or envelope-based speech. This study measured masking release for two other speech signals in which level variations were minimal: peak clipping and TFS processing of an envelope signal. Consonant identification was measured for hearing-impaired listeners in backgrounds of continuous and fluctuating speech-shaped noise. The normalized masking release obtained using speech with normal variations in overall level wa...

The Hearing Journal, 2007

Journal of the Acoustical Society of America, 2015

ABSTRACT

The Journal of the Acoustical Society of America, 2015

Consonant-identification ability was examined in normal-hearing (NH) and hearing-impaired (HI) li... more Consonant-identification ability was examined in normal-hearing (NH) and hearing-impaired (HI) listeners in the presence of steady-state and 10-Hz square-wave interrupted speech-shaped noise. The Hilbert transform was used to process speech stimuli (16 consonants in a-C-a syllables) to present envelope cues, temporal fine-structure (TFS) cues, or envelope cues recovered from TFS speech. The performance of the HI listeners was inferior to that of the NH listeners both in terms of lower levels of performance in the baseline condition and in the need for higher signal-to-noise ratio to yield a given level of performance. For NH listeners, scores were higher in interrupted noise than in steady-state noise for all speech types (indicating substantial masking release). For HI listeners, masking release was typically observed for TFS and recovered-envelope speech but not for unprocessed and envelope speech. For both groups of listeners, TFS and recovered-envelope speech yielded similar lev...

Proceedings of the 2001 IEEE Workshop on the Applications of Signal Processing to Audio and Acoustics (Cat. No.01TH8575)

Empirical transfer functions were measured for a manikin head as a function of source position (r... more Empirical transfer functions were measured for a manikin head as a function of source position (re: the listener) and listener position (re: the room) for sources within a meter of the listener. Empirical results are compared to room simulations using a standard image-method model combined with anechoic, distance-dependent head-related transfer functions (HRTFs). Results suggest that the biggest discrepancies between measured and modeled impulse responses arise due to interactions of the head with the source, which cannot be ignored for sources this close to the listener. Results give insight into the importance of the acoustic effects of the head and room on the total signal reaching a listener and have implications for understanding spatial perception in rooms and developing realistic 3-D spatial auditory displays.

African journal of computing and ICT, 2013

In this research, we explored the effect of noise interruption rate on speech intelligibility. Sp... more In this research, we explored the effect of noise interruption rate on speech intelligibility. Specifically, we used the Hearing In Noise Test (HINT) procedure with the original HINT stimuli (English) and Igbo stimuli to assess speech reception ability in interrupted noise. For a given noise level, the HINT test provides an estimate of the signal-to-noise ratio (SNR) required for 50%-correct speech intelligibility. The SNR for 50%-correct intelligibility changes depending upon the interruption rate of the noise. This phenomenon (called Masking Release) has been studied extensively in English but not for Igbo - which is an African tonal language spoken predominantly in South Eastern Nigeria. This experiment explored and compared the phenomenon of Masking Release for (i) native English speakers listening to English, (ii) native Igbo speakers listening to English, and (iii) native Igbo speakers listening to Igbo. Since Igbo is a tonal language and English is a non-tonal language, this ...

The Journal of the Acoustical Society of America, 2014

This article introduces and provides an assessment of a spatial-filtering algorithm based on two ... more This article introduces and provides an assessment of a spatial-filtering algorithm based on two closely-spaced (∼1 cm) microphones in a behind-the-ear shell. The evaluated spatial-filtering algorithm used fast (∼10 ms) temporal-spectral analysis to determine the location of incoming sounds and to enhance sounds arriving from straight ahead of the listener. Speech reception thresholds (SRTs) were measured for eight cochlear implant (CI) users using consonant and vowel materials under three processing conditions: An omni-directional response, a dipole-directional response, and the spatial-filtering algorithm. The background noise condition used three simultaneous time-reversed speech signals as interferers located at 90°, 180°, and 270°. Results indicated that the spatial-filtering algorithm can provide speech reception benefits of 5.8 to 10.7 dB SRT compared to an omni-directional response in a reverberant room with multiple noise sources. Given the observed SRT benefits, coupled wi...

Trends in amplification, 2012

Functional simulation of sensorineural hearing impairment is an important research tool that can ... more Functional simulation of sensorineural hearing impairment is an important research tool that can elucidate the nature of hearing impairments and suggest or eliminate compensatory signal-processing schemes. The objective of the current study was to evaluate the capability of an audibility-based functional simulation of hearing loss to reproduce the auditory-filter characteristics of listeners with sensorineural hearing loss. The hearing-loss simulation used either threshold-elevating noise alone or a combination of threshold-elevating noise and multiband expansion to reproduce the audibility-based characteristics of the loss (including detection thresholds, dynamic range, and loudness recruitment). The hearing losses of 10 listeners with bilateral, mild-to-severe hearing loss were simulated in 10 corresponding groups of 3 age-matched normal-hearing listeners. Frequency selectivity was measured using a notched-noise masking paradigm at five probe frequencies in the range of 250 to 400...

The Journal of the Acoustical Society of America, 2014

ABSTRACT

The Journal of the Acoustical Society of America, 2015

Narrowband speech can be separated into fast temporal cues [temporal fine structure (TFS)], and s... more Narrowband speech can be separated into fast temporal cues [temporal fine structure (TFS)], and slow amplitude modulations (envelope). Speech processed to contain only TFS leads to envelope recovery through cochlear filtering, which has been suggested to account for TFS-speech intelligibility for normal-hearing listeners. Hearing-impaired listeners have deficits with TFS-speech identification, but the contribution of recovered-envelope cues to these deficits is unknown. This was assessed for hearing-impaired listeners by measuring identification of disyllables processed to contain TFS or recovered-envelope cues. Hearing-impaired listeners performed worse than normalhearing listeners, but TFS-speech intelligibility was accounted for by recovered-envelope cues for both groups. V

The Journal of the Acoustical Society of America, 2010

The Journal of the Acoustical Society of America, 2009

Gap‐detection thresholds were measured in listeners with real and simulated hearing loss under co... more Gap‐detection thresholds were measured in listeners with real and simulated hearing loss under conditions of auditory or tactile presentation. The audiometric thresholds of each of ten listeners with sensorineural hearing loss (21–69 years of age) were simulated in groups of age‐matched normal‐hearing listeners through a combination of spectrally shaped masking noise and multiband expansion. The leading and trailing markers for the gap‐detection task were 250‐ and 400‐Hz sinusoids with a nominal duration of 100 ms. Gap‐detection thresholds for a nominal baseline gap of 0 ms were measured for four different combinations of leading and trailing markers (250–250, 250–400, 400–250, and 400–400 Hz) using a 3I, 2AFC procedure. Auditory measurements were obtained for monaural presentation over headphones using a marker level set to be equal to the maximum of 70 dB SPL or 10 dB SL. Tactile measurements were obtained using sinusoids presented to the left middle finger through an Alpha‐M AV‐6 vibrator at a level of 25 dB SL. Results are discussed in terms of (a) spectral‐disparity effects of leading and trailing markers; (b) relation of thresholds for auditory versus tactile presentation; and (c) comparisons of results from listeners with real and simulated hearing loss. [Work supported by NIH‐NIDCD R01 DC00117.]

The Journal of the Acoustical Society of America, 2009

Forward‐masking functions were obtained in eight listeners with moderate to severe sensorineural ... more Forward‐masking functions were obtained in eight listeners with moderate to severe sensorineural hearing loss (aged 21–69 years). The hearing loss of each impaired listener was simulated in a group of three age‐matched normal‐hearing listeners through a combination of spectrally shaped masking noise and multiband expansion. Forward masking was measured in both groups of listeners for probe signals at frequencies of 500, 1000, 2000, and 4000 Hz using an on‐frequency masker and two off‐frequency maskers (0.55 and 1.15 times the signal frequency) under a 3I, 2AFC procedure. The probe signal was presented at 5 dB SL; signals and maskers were gated with 5‐m on/off times with a steady‐state duration of 0 ms for probe signals and 100 ms for maskers; and values of masker‐offset time to signal‐onset time were in the range of 0 to 100 ms. Findings will be described in terms of the slopes of the masking functions for each combination of probe and masker frequency and the ratio of the slopes obtained with on‐ relativ...

The Journal of the Acoustical Society of America, 2009

The Journal of the Acoustical Society of America, 2017

The masking release (i.e., better speech recognition in fluctuating compared to continuous noise ... more The masking release (i.e., better speech recognition in fluctuating compared to continuous noise backgrounds) observed for normal-hearing (NH) listeners is generally reduced or absent in hearingimpaired (HI) listeners. One explanation for this lies in the effects of reduced audibility: elevated thresholds may prevent HI listeners from taking advantage of signals available to NH listeners during the dips of temporally fluctuating noise where the interference is relatively weak. This hypothesis was addressed through the development of a signal-processing technique designed to increase the audibility of speech during dips in interrupted noise. This technique acts to (i) compare shortterm and long-term estimates of energy, (ii) increase the level of short-term segments whose energy is below the average energy, and (iii) normalize the overall energy of the processed signal to be equivalent to that of the original long-term estimate. Evaluations of this energy-equalizing (EEQ) technique included consonant identification and sentence reception in backgrounds of continuous and regularly interrupted noise. For HI listeners, performance was generally similar for processed and unprocessed signals in continuous noise; however, superior performance for EEQ processing was observed in certain regularly interrupted noise backgrounds.

Trends in Hearing, 2017

The masking release (MR; i.e., better speech recognition in fluctuating compared with continuous ... more The masking release (MR; i.e., better speech recognition in fluctuating compared with continuous noise backgrounds) that is evident for listeners with normal hearing (NH) is generally reduced or absent for listeners with sensorineural hearing impairment (HI). In this study, a real-time signal-processing technique was developed to improve MR in listeners with HI and offer insight into the mechanisms influencing the size of MR. This technique compares short-term and long-term estimates of energy, increases the level of short-term segments whose energy is below the average energy, and normalizes the overall energy of the processed signal to be equivalent to that of the original long-term estimate. This signal-processing algorithm was used to create two types of energy-equalized (EEQ) signals: EEQ1, which operated on the wideband speech plus noise signal, and EEQ4, which operated independently on each of four bands with equal logarithmic width. Consonant identification was tested in backgrounds of continuous and various types of fluctuating speech-shaped Gaussian noise including those with both regularly and irregularly spaced temporal fluctuations. Listeners with HI achieved similar scores for EEQ and the original (unprocessed) stimuli in continuous-noise backgrounds, while superior performance was obtained for the EEQ signals in fluctuating background noises that had regular temporal gaps but not for those with irregularly spaced fluctuations. Thus, in noise backgrounds with regularly spaced temporal fluctuations, the energy-normalized signals led to larger values of MR and higher intelligibility than obtained with unprocessed signals.

The Journal of the Acoustical Society of America, 2017

Lou’s early work in the area of improved signal processing for hearing aids included his research... more Lou’s early work in the area of improved signal processing for hearing aids included his research on compression amplification to combat the effects of loudness recruitment in listeners with sensorineural hearing loss. Working with his doctoral students (including Rich Lippmann, Steve De Gennaro, and Diane Bustamante), Lou made major contributions towards an analytical understanding of the benefits and limitations of compression amplification as a component of hearing aids. Recently, Lou has been involved in work on a new signal-processing scheme which operates to equalize the energy in a speech signal over time. This energy-equalization (EEQ) scheme shares a similar goal with compression amplification in that they both attempt to match the range of speech levels into the reduced dynamic range of a listener with sensorineural loss. Their operation, however, is different: while compression amplification is based on the actual sound-pressure level of the signal, the EEQ scheme operates on relative energy ca...

The Journal of the Acoustical Society of America, 2016

Acoustic speech is marked by time-varying changes in the amplitude envelope that may pose difficu... more Acoustic speech is marked by time-varying changes in the amplitude envelope that may pose difficulties for hearing-impaired listeners. Removal of these variations (e.g., by the Hilbert transform) could improve speech reception for such listeners, particularly in fluctuating interference. Léger, Reed, Desloge, Swaminathan, and Braida [(2015b). J. Acoust. Soc. Am. 138, 389-403] observed that a normalized measure of masking release obtained for hearing-impaired listeners using speech processed to preserve temporal fine-structure (TFS) cues was larger than that for unprocessed or envelope-based speech. This study measured masking release for two other speech signals in which level variations were minimal: peak clipping and TFS processing of an envelope signal. Consonant identification was measured for hearing-impaired listeners in backgrounds of continuous and fluctuating speech-shaped noise. The normalized masking release obtained using speech with normal variations in overall level wa...

The Hearing Journal, 2007

Journal of the Acoustical Society of America, 2015

ABSTRACT

The Journal of the Acoustical Society of America, 2015

Consonant-identification ability was examined in normal-hearing (NH) and hearing-impaired (HI) li... more Consonant-identification ability was examined in normal-hearing (NH) and hearing-impaired (HI) listeners in the presence of steady-state and 10-Hz square-wave interrupted speech-shaped noise. The Hilbert transform was used to process speech stimuli (16 consonants in a-C-a syllables) to present envelope cues, temporal fine-structure (TFS) cues, or envelope cues recovered from TFS speech. The performance of the HI listeners was inferior to that of the NH listeners both in terms of lower levels of performance in the baseline condition and in the need for higher signal-to-noise ratio to yield a given level of performance. For NH listeners, scores were higher in interrupted noise than in steady-state noise for all speech types (indicating substantial masking release). For HI listeners, masking release was typically observed for TFS and recovered-envelope speech but not for unprocessed and envelope speech. For both groups of listeners, TFS and recovered-envelope speech yielded similar lev...

Proceedings of the 2001 IEEE Workshop on the Applications of Signal Processing to Audio and Acoustics (Cat. No.01TH8575)

Empirical transfer functions were measured for a manikin head as a function of source position (r... more Empirical transfer functions were measured for a manikin head as a function of source position (re: the listener) and listener position (re: the room) for sources within a meter of the listener. Empirical results are compared to room simulations using a standard image-method model combined with anechoic, distance-dependent head-related transfer functions (HRTFs). Results suggest that the biggest discrepancies between measured and modeled impulse responses arise due to interactions of the head with the source, which cannot be ignored for sources this close to the listener. Results give insight into the importance of the acoustic effects of the head and room on the total signal reaching a listener and have implications for understanding spatial perception in rooms and developing realistic 3-D spatial auditory displays.

African journal of computing and ICT, 2013

In this research, we explored the effect of noise interruption rate on speech intelligibility. Sp... more In this research, we explored the effect of noise interruption rate on speech intelligibility. Specifically, we used the Hearing In Noise Test (HINT) procedure with the original HINT stimuli (English) and Igbo stimuli to assess speech reception ability in interrupted noise. For a given noise level, the HINT test provides an estimate of the signal-to-noise ratio (SNR) required for 50%-correct speech intelligibility. The SNR for 50%-correct intelligibility changes depending upon the interruption rate of the noise. This phenomenon (called Masking Release) has been studied extensively in English but not for Igbo - which is an African tonal language spoken predominantly in South Eastern Nigeria. This experiment explored and compared the phenomenon of Masking Release for (i) native English speakers listening to English, (ii) native Igbo speakers listening to English, and (iii) native Igbo speakers listening to Igbo. Since Igbo is a tonal language and English is a non-tonal language, this ...

The Journal of the Acoustical Society of America, 2014

This article introduces and provides an assessment of a spatial-filtering algorithm based on two ... more This article introduces and provides an assessment of a spatial-filtering algorithm based on two closely-spaced (∼1 cm) microphones in a behind-the-ear shell. The evaluated spatial-filtering algorithm used fast (∼10 ms) temporal-spectral analysis to determine the location of incoming sounds and to enhance sounds arriving from straight ahead of the listener. Speech reception thresholds (SRTs) were measured for eight cochlear implant (CI) users using consonant and vowel materials under three processing conditions: An omni-directional response, a dipole-directional response, and the spatial-filtering algorithm. The background noise condition used three simultaneous time-reversed speech signals as interferers located at 90°, 180°, and 270°. Results indicated that the spatial-filtering algorithm can provide speech reception benefits of 5.8 to 10.7 dB SRT compared to an omni-directional response in a reverberant room with multiple noise sources. Given the observed SRT benefits, coupled wi...

Trends in amplification, 2012

Functional simulation of sensorineural hearing impairment is an important research tool that can ... more Functional simulation of sensorineural hearing impairment is an important research tool that can elucidate the nature of hearing impairments and suggest or eliminate compensatory signal-processing schemes. The objective of the current study was to evaluate the capability of an audibility-based functional simulation of hearing loss to reproduce the auditory-filter characteristics of listeners with sensorineural hearing loss. The hearing-loss simulation used either threshold-elevating noise alone or a combination of threshold-elevating noise and multiband expansion to reproduce the audibility-based characteristics of the loss (including detection thresholds, dynamic range, and loudness recruitment). The hearing losses of 10 listeners with bilateral, mild-to-severe hearing loss were simulated in 10 corresponding groups of 3 age-matched normal-hearing listeners. Frequency selectivity was measured using a notched-noise masking paradigm at five probe frequencies in the range of 250 to 400...

The Journal of the Acoustical Society of America, 2014

ABSTRACT

The Journal of the Acoustical Society of America, 2015

Narrowband speech can be separated into fast temporal cues [temporal fine structure (TFS)], and s... more Narrowband speech can be separated into fast temporal cues [temporal fine structure (TFS)], and slow amplitude modulations (envelope). Speech processed to contain only TFS leads to envelope recovery through cochlear filtering, which has been suggested to account for TFS-speech intelligibility for normal-hearing listeners. Hearing-impaired listeners have deficits with TFS-speech identification, but the contribution of recovered-envelope cues to these deficits is unknown. This was assessed for hearing-impaired listeners by measuring identification of disyllables processed to contain TFS or recovered-envelope cues. Hearing-impaired listeners performed worse than normalhearing listeners, but TFS-speech intelligibility was accounted for by recovered-envelope cues for both groups. V

The Journal of the Acoustical Society of America, 2010

The Journal of the Acoustical Society of America, 2009

Gap‐detection thresholds were measured in listeners with real and simulated hearing loss under co... more Gap‐detection thresholds were measured in listeners with real and simulated hearing loss under conditions of auditory or tactile presentation. The audiometric thresholds of each of ten listeners with sensorineural hearing loss (21–69 years of age) were simulated in groups of age‐matched normal‐hearing listeners through a combination of spectrally shaped masking noise and multiband expansion. The leading and trailing markers for the gap‐detection task were 250‐ and 400‐Hz sinusoids with a nominal duration of 100 ms. Gap‐detection thresholds for a nominal baseline gap of 0 ms were measured for four different combinations of leading and trailing markers (250–250, 250–400, 400–250, and 400–400 Hz) using a 3I, 2AFC procedure. Auditory measurements were obtained for monaural presentation over headphones using a marker level set to be equal to the maximum of 70 dB SPL or 10 dB SL. Tactile measurements were obtained using sinusoids presented to the left middle finger through an Alpha‐M AV‐6 vibrator at a level of 25 dB SL. Results are discussed in terms of (a) spectral‐disparity effects of leading and trailing markers; (b) relation of thresholds for auditory versus tactile presentation; and (c) comparisons of results from listeners with real and simulated hearing loss. [Work supported by NIH‐NIDCD R01 DC00117.]

The Journal of the Acoustical Society of America, 2009

Forward‐masking functions were obtained in eight listeners with moderate to severe sensorineural ... more Forward‐masking functions were obtained in eight listeners with moderate to severe sensorineural hearing loss (aged 21–69 years). The hearing loss of each impaired listener was simulated in a group of three age‐matched normal‐hearing listeners through a combination of spectrally shaped masking noise and multiband expansion. Forward masking was measured in both groups of listeners for probe signals at frequencies of 500, 1000, 2000, and 4000 Hz using an on‐frequency masker and two off‐frequency maskers (0.55 and 1.15 times the signal frequency) under a 3I, 2AFC procedure. The probe signal was presented at 5 dB SL; signals and maskers were gated with 5‐m on/off times with a steady‐state duration of 0 ms for probe signals and 100 ms for maskers; and values of masker‐offset time to signal‐onset time were in the range of 0 to 100 ms. Findings will be described in terms of the slopes of the masking functions for each combination of probe and masker frequency and the ratio of the slopes obtained with on‐ relativ...

The Journal of the Acoustical Society of America, 2009