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Pastore MT, Pulling KR, Chen C, Yost WA, Dorman MF. Synchronizing Automatic Gain Control in Bilateral Cochlear Implants Mitigates Dynamic Localization Deficits Introduced by Independent Bilateral Compression. Ear Hear 2024:00003446-990000000-00262. [PMID: 38472134 DOI: 10.1097/aud.0000000000001492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
OBJECTIVES The independence of left and right automatic gain controls (AGCs) used in cochlear implants can distort interaural level differences and thereby compromise dynamic sound source localization. We assessed the degree to which synchronizing left and right AGCs mitigates those difficulties as indicated by listeners' ability to use the changes in interaural level differences that come with head movements to avoid front-back reversals (FBRs). DESIGN Broadband noise stimuli were presented from one of six equally spaced loudspeakers surrounding the listener. Sound source identification was tested for stimuli presented at 70 dBA (above AGC threshold) for 10 bilateral cochlear implant patients, under conditions where (1) patients remained stationary and (2) free head movements within ±30° were encouraged. These conditions were repeated for both synchronized and independent AGCs. The same conditions were run at 50 dBA, below the AGC threshold, to assess listeners' baseline performance when AGCs were not engaged. In this way, the expected high variability in listener performance could be separated from effects of independent AGCs to reveal the degree to which synchronizing AGCs could restore localization performance to what it was without AGC compression. RESULTS The mean rate of FBRs was higher for sound stimuli presented at 70 dBA with independent AGCs, both with and without head movements, than at 50 dBA, suggesting that when AGCs were independently engaged they contributed to poorer front-back localization. When listeners remained stationary, synchronizing AGCs did not significantly reduce the rate of FBRs. When AGCs were independent at 70 dBA, head movements did not have a significant effect on the rate of FBRs. Head movements did have a significant group effect on the rate of FBRs at 50 dBA when AGCs were not engaged and at 70 dBA when AGCs were synchronized. Synchronization of AGCs, together with head movements, reduced the rate of FBRs to approximately what it was in the 50-dBA baseline condition. Synchronizing AGCs also had a significant group effect on listeners' overall percent correct localization. CONCLUSIONS Synchronizing AGCs allowed for listeners to mitigate front-back confusions introduced by unsynchronized AGCs when head motion was permitted, returning individual listener performance to roughly what it was in the 50-dBA baseline condition when AGCs were not engaged. Synchronization of AGCs did not overcome localization deficiencies which were observed when AGCs were not engaged, and which are therefore unrelated to AGC compression.
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Affiliation(s)
- M Torben Pastore
- College of Health Solutions, Arizona State University, Tempe, Arizona, USA
| | - Kathryn R Pulling
- College of Health Solutions, Arizona State University, Tempe, Arizona, USA
| | - Chen Chen
- Advanced Bionics, Valencia, California, USA
| | - William A Yost
- College of Health Solutions, Arizona State University, Tempe, Arizona, USA
| | - Michael F Dorman
- College of Health Solutions, Arizona State University, Tempe, Arizona, USA
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Valzolgher C, Capra S, Sum K, Finos L, Pavani F, Picinali L. Spatial hearing training in virtual reality with simulated asymmetric hearing loss. Sci Rep 2024; 14:2469. [PMID: 38291126 PMCID: PMC10827792 DOI: 10.1038/s41598-024-51892-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 01/10/2024] [Indexed: 02/01/2024] Open
Abstract
Sound localization is essential to perceive the surrounding world and to interact with objects. This ability can be learned across time, and multisensory and motor cues play a crucial role in the learning process. A recent study demonstrated that when training localization skills, reaching to the sound source to determine its position reduced localization errors faster and to a greater extent as compared to just naming sources' positions, despite the fact that in both tasks, participants received the same feedback about the correct position of sound sources in case of wrong response. However, it remains to establish which features have made reaching to sound more effective as compared to naming. In the present study, we introduced a further condition in which the hand is the effector providing the response, but without it reaching toward the space occupied by the target source: the pointing condition. We tested three groups of participants (naming, pointing, and reaching groups) each while performing a sound localization task in normal and altered listening situations (i.e. mild-moderate unilateral hearing loss) simulated through auditory virtual reality technology. The experiment comprised four blocks: during the first and the last block, participants were tested in normal listening condition, while during the second and the third in altered listening condition. We measured their performance, their subjective judgments (e.g. effort), and their head-related behavior (through kinematic tracking). First, people's performance decreased when exposed to asymmetrical mild-moderate hearing impairment, more specifically on the ipsilateral side and for the pointing group. Second, we documented that all groups decreased their localization errors across altered listening blocks, but the extent of this reduction was higher for reaching and pointing as compared to the naming group. Crucially, the reaching group leads to a greater error reduction for the side where the listening alteration was applied. Furthermore, we documented that, across blocks, reaching and pointing groups increased the implementation of head motor behavior during the task (i.e., they increased approaching head movements toward the space of the sound) more than naming. Third, while performance in the unaltered blocks (first and last) was comparable, only the reaching group continued to exhibit a head behavior similar to those developed during the altered blocks (second and third), corroborating the previous observed relationship between the reaching to sounds task and head movements. In conclusion, this study further demonstrated the effectiveness of reaching to sounds as compared to pointing and naming in the learning processes. This effect could be related both to the process of implementing goal-directed motor actions and to the role of reaching actions in fostering the implementation of head-related motor strategies.
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Affiliation(s)
- Chiara Valzolgher
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Corso Bettini 31, 38068, Rovereto, TN, Italy.
| | - Sara Capra
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Corso Bettini 31, 38068, Rovereto, TN, Italy
| | - Kevin Sum
- Audio Experience Design (www.axdesign.co.uk), Imperial College London, London, UK
| | - Livio Finos
- Department of Statistical Sciences, University of Padova, Padova, Italy
| | - Francesco Pavani
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Corso Bettini 31, 38068, Rovereto, TN, Italy
- Department of Psychology and Cognitive Sciences (DiPSCo), University of Trento, Rovereto, Italy
- Centro Interuniversitario di Ricerca "Cognizione, Linguaggio e Sordità" (CIRCLeS), Rovereto, Italy
| | - Lorenzo Picinali
- Audio Experience Design (www.axdesign.co.uk), Imperial College London, London, UK
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Mai J, Gargiullo R, Zheng M, Esho V, Hussein OE, Pollay E, Bowe C, Williamson LM, McElroy AF, Goolsby WN, Brooks KA, Rodgers CC. Sound-seeking before and after hearing loss in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574475. [PMID: 38260458 PMCID: PMC10802496 DOI: 10.1101/2024.01.08.574475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
How we move our bodies affects how we perceive sound. For instance, we can explore an environment to seek out the source of a sound and we can use head movements to compensate for hearing loss. How we do this is not well understood because many auditory experiments are designed to limit head and body movements. To study the role of movement in hearing, we developed a behavioral task called sound-seeking that rewarded mice for tracking down an ongoing sound source. Over the course of learning, mice more efficiently navigated to the sound. We then asked how auditory behavior was affected by hearing loss induced by surgical removal of the malleus from the middle ear. An innate behavior, the auditory startle response, was abolished by bilateral hearing loss and unaffected by unilateral hearing loss. Similarly, performance on the sound-seeking task drastically declined after bilateral hearing loss and did not recover. In striking contrast, mice with unilateral hearing loss were only transiently impaired on sound-seeking; over a recovery period of about a week, they regained high levels of performance, increasingly reliant on a different spatial sampling strategy. Thus, even in the face of permanent unilateral damage to the peripheral auditory system, mice recover their ability to perform a naturalistic sound-seeking task. This paradigm provides an opportunity to examine how body movement enables better hearing and resilient adaptation to sensory deprivation.
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Affiliation(s)
- Jessica Mai
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Rowan Gargiullo
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Megan Zheng
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Valentina Esho
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Osama E Hussein
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Eliana Pollay
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
| | - Cedric Bowe
- Neuroscience Graduate Program, Emory University, Atlanta GA 30322
| | | | | | - William N Goolsby
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322
| | - Kaitlyn A Brooks
- Department of Otolaryngology - Head and Neck Surgery, Emory University School of Medicine, Atlanta GA 30308
| | - Chris C Rodgers
- Department of Neurosurgery, Emory University School of Medicine, Atlanta GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322
- Department of Biomedical Engineering, Georgia Tech and Emory University School of Medicine, Atlanta GA 30322
- Department of Biology, Emory College of Arts and Sciences, Atlanta GA 30322
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Yost WA. Randomizing spectral cues used to resolve front-back reversals in sound-source localization. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:661-670. [PMID: 37540095 PMCID: PMC10404140 DOI: 10.1121/10.0020563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 07/05/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023]
Abstract
Front-back reversals (FBRs) in sound-source localization tasks due to cone-of-confusion errors on the azimuth plane occur with some regularity, and their occurrence is listener-dependent. There are fewer FBRs for wideband, high-frequency sounds than for low-frequency sounds presumably because the sources of low-frequency sounds are localized on the basis of interaural differences (interaural time and level differences), which can lead to ambiguous responses. Spectral cues can aid in determining sound-source locations for wideband, high-frequency sounds, and such spectral cues do not lead to ambiguous responses. However, to what extent spectral features might aid sound-source localization is still not known. This paper explores conditions in which the spectral profile of two-octave wide noise bands, whose sources were localized on the azimuth plane, were randomly varied. The experiment demonstrated that such spectral profile randomization increased FBRs for high-frequency noise bands, presumably because whatever spectral features are used for sound-source localization were no longer as useful for resolving FBRs, and listeners relied on interaural differences for sound-source localization, which led to response ambiguities. Additionally, head rotation decreased FBRs in all cases, even when FBRs increased due to spectral profile randomization. In all cases, the occurrence of FBRs was listener-dependent.
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Affiliation(s)
- William A Yost
- Spatial Hearing Lab, College of Health Solutions, Arizona State University, Tempe, Arizona 85004, USA
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Morris B, Cosetti M, Kelly J, Yang J, Harel D, Medlin A, Lubetzky AV. Differing postural control patterns in individuals with bilateral and unilateral hearing loss. Am J Otolaryngol 2023; 44:103866. [PMID: 36989756 DOI: 10.1016/j.amjoto.2023.103866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 03/19/2023] [Indexed: 03/30/2023]
Abstract
OBJECTIVES Hearing loss (HL) is associated with imbalance and increased fall risk. The mechanism underlying this relationship and differences across types of hearing loss remains unclear. Head mounted displays (HMD) can shed light on postural control mechanisms via an analysis of head sway. PURPOSE The purpose of this study was to evaluate head sway in response to sensory perturbations in individuals with bilateral (BHL) or unilateral hearing loss (UHL) and compare them to controls. MATERIALS AND METHODS We recruited 36 controls, 23 individuals with UHL and 14 with BHL. An HMD (HTC Vive) measured head sway while participants stood on the floor, hips-width apart. Stimuli included two levels of visuals and sound. Root Mean Square Velocity (RMSV) and Power Spectral Density (PSD) were used to quantify head sway. RESULTS Adjusting for age, individuals with BHL had significantly higher anterior-posterior and medio-lateral RMSV than controls and individuals with UHL. Individuals with UHL demonstrated significantly lower response to visual perturbations in RMSV AP and in all 3 frequency segments of PSD compared to controls. Individuals with UHL showed significantly lower movements at high frequencies compared to controls. Sounds or severity of HL did not impact head sway. CONCLUSIONS Individuals with BHL demonstrated increased sway with visual perturbations and should be clinically assessed for balance performance and fall risk. Individuals with UHL exhibited reduced responses to visual stimuli compared with controls, which may reflect conscious movement processing. Additional studies are needed to further understand the mechanistic relationship between hearing loss and imbalance.
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Affiliation(s)
- Brittani Morris
- Department of Physical Therapy, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY, United States of America.
| | - Maura Cosetti
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America
| | - Jennifer Kelly
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America; Vestibular Rehabilitations, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America
| | - Junhui Yang
- Department of Mathematics and Statistics, College of Natural Sciences, University of Massachusetts Amherst, Amherst, MA, United States of America
| | - Daphna Harel
- Department of Applied Statistics, Social Science and Humanities, Steinhardt School of Culture Education and Human Development, New York University, New York, NY, United States of America
| | - Andrew Medlin
- Department of Physical Therapy, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY, United States of America
| | - Anat V Lubetzky
- Department of Physical Therapy, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY, United States of America
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Gordon KA, Alemu R, Papsin BC, Negandhi J, Cushing SL. Effects of Age at Implantation on Outcomes of Cochlear Implantation in Children with Short Durations of Single-Sided Deafness. Otol Neurotol 2023; 44:233-240. [PMID: 36728258 PMCID: PMC9924958 DOI: 10.1097/mao.0000000000003811] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Children with single-sided deafness (SSD) show reduced language and academic development and report hearing challenges. We aim to improve outcomes in children with SSD by providing bilateral hearing through cochlear implantation of the deaf ear with minimal delay. STUDY DESIGN Prospective cohort study of 57 children with SSD provided with cochlear implant (CI) between May 13, 2013, and June 25, 2021. SETTING Tertiary children's hospital. PARTICIPANTS Children with early onset (n = 40) or later onset of SSD (n = 17) received CIs at ages 2.47 ± 1.58 years (early onset group) and 11.67 ± 3.91 years (late onset group) (mean ± SD). Duration of unilateral deafness was limited (mean ± SD = 1.93 ± 1.56 yr). INTERVENTION Cochlear implantation of the deaf ear. MAIN OUTCOMES/MEASURES Evaluations of device use (data logging) and hearing (speech perception, effects of spatial release from masking on speech detection, localization of stationary and moving sound, self-reported hearing questionnaires). RESULTS Results indicated that daily device use is variable (mean ± SD = 5.60 ± 2.97, range = 0.0-14.7 h/d) with particular challenges during extended COVID-19 lockdowns, including school closures (daily use reduced by mean 1.73 h). Speech perception with the CI alone improved (mean ± SD = 65.7 ± 26.4 RAU) but, in the late onset group, remained poorer than in the normal hearing ear. Measures of spatial release from masking also showed asymmetric hearing in the late onset group ( t13 = 5.14, p = 0.001). Localization of both stationary and moving sound was poor (mean ± SD error = 34.6° ± 16.7°) but slightly improved on the deaf side with CI use ( F1,36 = 3.95, p = 0.05). Decreased sound localization significantly correlated with poorer self-reported hearing. CONCLUSIONS AND RELEVANCE Benefits of CI in children with limited durations of SSD may be more restricted for older children/adolescents. Spatial hearing challenges remain. Efforts to increase CI acceptance and consistent use are needed.
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Affiliation(s)
- Karen A. Gordon
- Department of Otolaryngology–Head and Neck Surgery, University of Toronto
- Archie’s Cochlear Implant Laboratory, The Hospital for Sick Children
- Department of Communication Disorders, The Hospital for Sick Children
| | - Robel Alemu
- Archie’s Cochlear Implant Laboratory, The Hospital for Sick Children
| | - Blake C. Papsin
- Department of Otolaryngology–Head and Neck Surgery, University of Toronto
- Archie’s Cochlear Implant Laboratory, The Hospital for Sick Children
- Department of Otolaryngology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jaina Negandhi
- Archie’s Cochlear Implant Laboratory, The Hospital for Sick Children
| | - Sharon L. Cushing
- Department of Otolaryngology–Head and Neck Surgery, University of Toronto
- Archie’s Cochlear Implant Laboratory, The Hospital for Sick Children
- Department of Otolaryngology, The Hospital for Sick Children, Toronto, ON, Canada
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Tolisano AM, Pillion EM, Dirks CE, Ryan MT, Bernstein JGW. Quality of Life Impact of Cochlear Implantation for Single-Sided Deafness: Assessing the Interrelationship of Objective and Subjective Measures. Otol Neurotol 2023; 44:e125-e132. [PMID: 36728614 DOI: 10.1097/mao.0000000000003783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine the effect on quality of life (QOL) of cochlear implantation (CI) for single-sided deafness (SSD) and asymmetric hearing loss (AHL) using the first psychometrically developed CI-specific QOL tool for English-speaking patients and to assess its relationship to objective perceptual measures. STUDY DESIGN Retrospective cohort study. SETTING Tertiary-care medical center. PATIENTS English-speaking adults with SSD or AHL. INTERVENTIONS Unilateral CI. MAIN OUTCOME MEASURES Cochlear Implant Quality of Life (CIQOL) score, CI-alone speech-in-quiet (SIQ) score (CNC and AzBio), binaural speech-in-noise (SIN) threshold, binaural azimuthal sound localization (SL) error. RESULTS At the most recent postoperative evaluation (median, 9.3 months postimplantation), 25 of 28 subjects (89%) had a CIQOL improvement, with the improvement considered clinically beneficial (>3 points) for 18 of 28 subjects (64%). Group-mean CIQOL improvement was observed at the first postoperative visit and did not change significantly thereafter. Objective perceptual measures (SL, SIQ, SIN) continued to improve over 12 months after implantation. Linear mixed-model regression analyses showed a moderate positive correlation between SIN and SIQ improvements (r = 0.50 to 0.59, p < 0.0001) and a strong positive correlation between the improvement in the two SIQ measures (r = 0.89, p < 0.0001). No significant relationships were observed ( p > 0.05) among QOL or the objective perceptual measures. CONCLUSIONS QOL improved for the majority of subjects implanted for SSD and AHL. Different time courses for improvement in QOL and audiologic tests, combined with the lack of significant relationships among them, suggest that QOL outcomes reflect different aspects of the CI experience than those captured by speech-understanding and localization measures. SIQ may substitute for SIN when clinical constraints exist.
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Affiliation(s)
| | - Elicia M Pillion
- Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland
| | - Coral E Dirks
- Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland
| | - Matthew T Ryan
- Department of Otolaryngology-Head and Neck Surgery, Walter Reed National Military Medical Center, Bethesda, Maryland
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McLachlan G, Majdak P, Reijniers J, Mihocic M, Peremans H. Dynamic spectral cues do not affect human sound localization during small head movements. Front Neurosci 2023; 17:1027827. [PMID: 36816108 PMCID: PMC9936143 DOI: 10.3389/fnins.2023.1027827] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Natural listening involves a constant deployment of small head movement. Spatial listening is facilitated by head movements, especially when resolving front-back confusions, an otherwise common issue during sound localization under head-still conditions. The present study investigated which acoustic cues are utilized by human listeners to localize sounds using small head movements (below ±10° around the center). Seven normal-hearing subjects participated in a sound localization experiment in a virtual reality environment. Four acoustic cue stimulus conditions were presented (full spectrum, flattened spectrum, frozen spectrum, free-field) under three movement conditions (no movement, head rotations over the yaw axis and over the pitch axis). Localization performance was assessed using three metrics: lateral and polar precision error and front-back confusion rate. Analysis through mixed-effects models showed that even small yaw rotations provide a remarkable decrease in front-back confusion rate, whereas pitch rotations did not show much of an effect. Furthermore, MSS cues improved localization performance even in the presence of dITD cues. However, performance was similar between stimuli with and without dMSS cues. This indicates that human listeners utilize the MSS cues before the head moves, but do not rely on dMSS cues to localize sounds when utilizing small head movements.
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Affiliation(s)
- Glen McLachlan
- Department of Engineering Management, University of Antwerp, Antwerp, Belgium,*Correspondence: Glen McLachlan ✉
| | - Piotr Majdak
- Acoustics Research Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Jonas Reijniers
- Department of Engineering Management, University of Antwerp, Antwerp, Belgium
| | - Michael Mihocic
- Acoustics Research Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Herbert Peremans
- Department of Engineering Management, University of Antwerp, Antwerp, Belgium
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Dirks CE, Nelson PB, Oxenham AJ. No Benefit of Deriving Cochlear-Implant Maps From Binaural Temporal-Envelope Sensitivity for Speech Perception or Spatial Hearing Under Single-Sided Deafness. Ear Hear 2022; 43:310-322. [PMID: 34291758 PMCID: PMC8770730 DOI: 10.1097/aud.0000000000001094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES This study tested whether speech perception and spatial acuity improved in people with single-sided deafness and a cochlear implant (SSD+CI) when the frequency allocation table (FAT) of the CI was adjusted to optimize frequency-dependent sensitivity to binaural disparities. DESIGN Nine SSD+CI listeners with at least 6 months of CI listening experience participated. Individual experimental FATs were created to best match the frequency-to-place mapping across ears using either sensitivity to binaural temporal-envelope disparities or estimated insertion depth. Spatial localization ability was measured, along with speech perception in spatially collocated or separated noise, first with the clinical FATs and then with the experimental FATs acutely and at 2-month intervals for 6 months. Listeners then returned to the clinical FATs and were retested acutely and after 1 month to control for long-term learning effects. RESULTS The experimental FAT varied between listeners, differing by an average of 0.15 octaves from the clinical FAT. No significant differences in performance were observed in any of the measures between the experimental FAT after 6 months and the clinical FAT one month later, and no clear relationship was found between the size of the frequency-allocation shift and perceptual changes. CONCLUSION Adjusting the FAT to optimize sensitivity to interaural temporal-envelope disparities did not improve localization or speech perception. The clinical frequency-to-place alignment may already be sufficient, given the inherently poor spectral resolution of CIs. Alternatively, other factors, such as temporal misalignment between the two ears, may need to be addressed before any benefits of spectral alignment can be observed.
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Affiliation(s)
- Coral E Dirks
- Department of Speech-Language-Hearing Sciences, University of Minnesota, Minneapolis, Minnesota, USA
- Center for Applied and Translational Sensory Sciences, Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Peggy B Nelson
- Department of Speech-Language-Hearing Sciences, University of Minnesota, Minneapolis, Minnesota, USA
- Center for Applied and Translational Sensory Sciences, Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew J Oxenham
- Center for Applied and Translational Sensory Sciences, Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
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Arras T, Snapp H, Sangen A, Snels C, Kuntz I, Theunen T, Kheirkhah K, Zarowski A, Wesarg T, van Wieringen A, Agterberg MJH. Instant improvement in monaural spatial hearing abilities through cognitive feedback. Exp Brain Res 2022; 240:1357-1369. [PMID: 35238954 PMCID: PMC9038864 DOI: 10.1007/s00221-022-06333-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 02/09/2022] [Indexed: 11/04/2022]
Abstract
Several studies report that sound localization performance of acute and chronic monauralized normal-hearing listeners can improve through training. Typically, training sessions are administered daily for several days or weeks. While this intensive training is effective, it may also be that monaural localization abilities improve instantly after providing explicit top-down information about the direction dependent change in timbre and level. The aim of the present study was to investigate whether cognitive feedback (i.e., top-down information) could instantly improve sound localization in naive acutely monauralized listeners. Forty-three normal-hearing listeners (experimental group), divided over five different centers, were tested. Two control groups, consisting of, respectively, nine and eleven normal-hearing listeners, were tested in one center. Broadband sounds (0.5-20 kHz) were presented from visible loudspeakers, positioned in azimuth (- 90° to 90°). Participants in the experimental group received explicit information about the noticeable difference in timbre and the poor localization in the monauralized listening condition, resulting in an instant improvement in sound localization abilities. With subsequent roving of stimulus level (20 dB), sound localization performance deteriorated immediately. The reported improvement is related to the context of the localization test. The results provide important implications for studies investigating sound localization in a clinical setting, especially during closed-set testing, and indicate the importance of top-down information.
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Affiliation(s)
- Tine Arras
- Department of Neurosciences, Experimental ORL, KU Leuven, University of Leuven, Leuven, Belgium
| | - Hillary Snapp
- Department of Otolaryngology, University of Miami, Miami, FL, USA
| | - Anouk Sangen
- Department of Neurosciences, Experimental ORL, KU Leuven, University of Leuven, Leuven, Belgium
| | - Chantal Snels
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands.,Department of Otorhinolaryngology, University Ghent, Ghent, Belgium
| | - Iris Kuntz
- Department of Otorhinolaryngology-Head and Neck Surgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Tinne Theunen
- ENT Department Sint-Augustinus Antwerp, European Institute For ORL, Antwerp, Belgium
| | - Kiana Kheirkhah
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Andrzej Zarowski
- ENT Department Sint-Augustinus Antwerp, European Institute For ORL, Antwerp, Belgium
| | - Thomas Wesarg
- Department of Otorhinolaryngology-Head and Neck Surgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Astrid van Wieringen
- Department of Neurosciences, Experimental ORL, KU Leuven, University of Leuven, Leuven, Belgium
| | - Martijn J H Agterberg
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands. .,Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
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Kim JH, Shim L, Bahng J, Lee HJ. Proficiency in Using Level Cue for Sound Localization Is Related to the Auditory Cortical Structure in Patients With Single-Sided Deafness. Front Neurosci 2021; 15:749824. [PMID: 34707477 PMCID: PMC8542703 DOI: 10.3389/fnins.2021.749824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Spatial hearing, which largely relies on binaural time/level cues, is a challenge for patients with asymmetric hearing. The degree of the deficit is largely variable, and better sound localization performance is frequently reported. Studies on the compensatory mechanism revealed that monaural level cues and monoaural spectral cues contribute to variable behavior in those patients who lack binaural spatial cues. However, changes in the monaural level cues have not yet been separately investigated. In this study, the use of the level cue in sound localization was measured using stimuli of 1 kHz at a fixed level in patients with single-sided deafness (SSD), the most severe form of asymmetric hearing. The mean absolute error (MAE) was calculated and related to the duration/age onset of SSD. To elucidate the biological correlate of this variable behavior, sound localization ability was compared with the cortical volume of the parcellated auditory cortex. In both SSD patients (n = 26) and normal controls with one ear acutely plugged (n = 23), localization performance was best on the intact ear side; otherwise, there was wide interindividual variability. In the SSD group, the MAE on the intact ear side was worse than that of the acutely plugged controls, and it deteriorated with longer duration/younger age at SSD onset. On the impaired ear side, MAE improved with longer duration/younger age at SSD onset. Performance asymmetry across lateral hemifields decreased in the SSD group, and the maximum decrease was observed with the most extended duration/youngest age at SSD onset. The decreased functional asymmetry in patients with right SSD was related to greater cortical volumes in the right posterior superior temporal gyrus and the left planum temporale, which are typically involved in auditory spatial processing. The study results suggest that structural plasticity in the auditory cortex is related to behavioral changes in sound localization when utilizing monaural level cues in patients with SSD.
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Affiliation(s)
- Ja Hee Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Chuncheon, South Korea.,Laboratory of Brain & Cognitive Sciences for Convergence Medicine, Hallym University College of Medicine, Anyang, South Korea
| | - Leeseul Shim
- Laboratory of Brain & Cognitive Sciences for Convergence Medicine, Hallym University College of Medicine, Anyang, South Korea
| | - Junghwa Bahng
- Department of Audiology and Speech-Language Pathology, Hallym University of Graduate Studies, Seoul, South Korea
| | - Hyo-Jeong Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Chuncheon, South Korea.,Laboratory of Brain & Cognitive Sciences for Convergence Medicine, Hallym University College of Medicine, Anyang, South Korea
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Single-Sided Deafness Cochlear Implant Sound-Localization Behavior With Multiple Concurrent Sources. Ear Hear 2021; 43:206-219. [PMID: 34320529 DOI: 10.1097/aud.0000000000001089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES For listeners with one deaf ear and the other ear with normal/near-normal hearing (single-sided deafness [SSD]) or moderate hearing loss (asymmetric hearing loss), cochlear implants (CIs) can improve speech understanding in noise and sound-source localization. Previous SSD-CI localization studies have used a single source with artificial sounds such as clicks or random noise. While this approach provides insights regarding the auditory cues that facilitate localization, it does not capture the complex nature of localization behavior in real-world environments. This study examined SSD-CI sound localization in a complex scenario where a target sound was added to or removed from a mixture of other environmental sounds, while tracking head movements to assess behavioral strategy. DESIGN Eleven CI users with normal hearing or moderate hearing loss in the contralateral ear completed a sound-localization task in monaural (CI-OFF) and bilateral (CI-ON) configurations. Ten of the listeners were also tested before CI activation to examine longitudinal effects. Two-second environmental sound samples, looped to create 4- or 10-sec trials, were presented in a spherical array of 26 loudspeakers encompassing ±144° azimuth and ±30° elevation at a 1-m radius. The target sound was presented alone (localize task) or concurrently with one or three additional sources presented to different loudspeakers, with the target cued by being added to (Add) or removed from (Rem) the mixture after 6 sec. A head-mounted tracker recorded movements in six dimensions (three for location, three for orientation). Mixed-model regression was used to examine target sound-identification accuracy, localization accuracy, and head movement. Angular and translational head movements were analyzed both before and after the target was switched on or off. RESULTS Listeners showed improved localization accuracy in the CI-ON configuration, but there was no interaction with test condition and no effect of the CI on sound-identification performance. Although high-frequency hearing loss in the unimplanted ear reduced localization accuracy and sound-identification performance, the magnitude of the CI localization benefit was independent of hearing loss. The CI reduced the magnitude of gross head movements used during the task in the azimuthal rotation and translational dimensions, both while the target sound was present (in all conditions) and during the anticipatory period before the target was switched on (in the Add condition). There was no change in pre- versus post-activation CI-OFF performance. CONCLUSIONS These results extend previous findings, demonstrating a CI localization benefit in a complex listening scenario that includes environmental and behavioral elements encountered in everyday listening conditions. The CI also reduced the magnitude of gross head movements used to perform the task. This was the case even before the target sound was added to the mixture. This suggests that a CI can reduce the need for physical movement both in anticipation of an upcoming sound event and while actively localizing the target sound. Overall, these results show that for SSD listeners, a CI can improve localization in a complex sound environment and reduce the amount of physical movement used.
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Pastore MT, Pulling KR, Chen C, Yost WA, Dorman MF. Effects of Bilateral Automatic Gain Control Synchronization in Cochlear Implants With and Without Head Movements: Sound Source Localization in the Frontal Hemifield. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2021; 64:2811-2824. [PMID: 34100627 PMCID: PMC8632503 DOI: 10.1044/2021_jslhr-20-00493] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/31/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Purpose For bilaterally implanted patients, the automatic gain control (AGC) in both left and right cochlear implant (CI) processors is usually neither linked nor synchronized. At high AGC compression ratios, this lack of coordination between the two processors can distort interaural level differences, the only useful interaural difference cue available to CI patients. This study assessed the improvement, if any, in the utility of interaural level differences for sound source localization in the frontal hemifield when AGCs were synchronized versus independent and when listeners were stationary versus allowed to move their heads. Method Sound source identification of broadband noise stimuli was tested for seven bilateral CI patients using 13 loudspeakers in the frontal hemifield, under conditions where AGCs were linked and unlinked. For half the conditions, patients remained stationary; in the other half, they were encouraged to rotate or reorient their heads within a range of approximately ± 30° during sound presentation. Results In general, those listeners who already localized reasonably well with independent AGCs gained the least from AGC synchronization, perhaps because there was less room for improvement. Those listeners who performed worst with independent AGCs gained the most from synchronization. All listeners performed as well or better with synchronization than without; however, intersubject variability was high. Head movements had little impact on the effectiveness of synchronization of AGCs. Conclusion Synchronization of AGCs offers one promising strategy for improving localization performance in the frontal hemifield for bilaterally implanted CI patients. Supplemental Material https://doi.org/10.23641/asha.14681412.
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