scholarly journals Locus coeruleus activity improves cochlear implant performance

Author(s):  
Robert Froemke ◽  
Erin Glennon ◽  
Angela Zhu ◽  
Youssef Zaim Wadghiri ◽  
Mario Svirksy

Abstract Cochlear implants are neuroprosthetic devices that can provide hearing to deaf patients1. Despite significant benefits offered by cochlear implants, there are highly variable outcomes in how quickly hearing is restored and perceptual accuracy after months or years of use2,3. Cochlear implant use is believed to require neuroplasticity within the central auditory system, and differential engagement of neuroplastic mechanisms might contribute to outcome variability4-7. Despite extensive studies on how cochlear implants activate the auditory system4,8-12, our understanding of cochlear implant-related neuroplasticity remains limited. One potent factor enabling plasticity is the neuromodulator norepinephrine from the brainstem locus coeruleus. Here we examined behavioral responses and neural activity in locus coeruleus and auditory cortex of deafened rats fitted with multi-channel cochlear implants. Animals were trained on a reward-based auditory task, with considerable individual differences of learning rates and maximum performance. Photometry from locus coeruleus predicted when implanted subjects would begin responding to sounds and longer-term perceptual accuracy, which were augmented by optogenetic locus coeruleus stimulation. Auditory cortical responses to cochlear implant stimulation reflected behavioral performance, with enhanced responses to rewarded stimuli and decreased distinction between unrewarded stimuli. Adequate engagement of central neuromodulatory systems is thus a potential clinically-relevant target for optimizing neuroprosthetic device use.

2021 ◽  
Author(s):  
Erin Glennon ◽  
Angela Zhu ◽  
Youssef Z. Wadghiri ◽  
Mario A. Svirsky ◽  
Robert C. Froemke

Cochlear implants are neuroprosthetic devices that can provide hearing to deaf patients1. Despite significant benefits offered by cochlear implants, there are highly variable outcomes in how quickly hearing is restored and perceptual accuracy after months or years of use2,3. Cochlear implant use is believed to require neuroplasticity within the central auditory system, and differential engagement of neuroplastic mechanisms might contribute to outcome variability4-7. Despite extensive studies on how cochlear implants activate the auditory system4,8-12, our understanding of cochlear implant-related neuroplasticity remains limited. One potent factor enabling plasticity is the neuromodulator norepinephrine from the brainstem locus coeruleus. Here we examined behavioral responses and neural activity in locus coeruleus and auditory cortex of deafened rats fitted with multi-channel cochlear implants. Animals were trained on a reward-based auditory task, with considerable individual differences of learning rates and maximum performance. Photometry from locus coeruleus predicted when implanted subjects would begin responding to sounds and longer-term perceptual accuracy, which were augmented by optogenetic locus coeruleus stimulation. Auditory cortical responses to cochlear implant stimulation reflected behavioral performance, with enhanced responses to rewarded stimuli and decreased distinction between unrewarded stimuli. Adequate engagement of central neuromodulatory systems is thus a potential clinically-relevant target for optimizing neuroprosthetic device use.


2016 ◽  
Vol 116 (2) ◽  
pp. 844-858 ◽  
Author(s):  
Julia King ◽  
Ina Shehu ◽  
J. Thomas Roland ◽  
Mario A. Svirsky ◽  
Robert C. Froemke

Cochlear implants are neuroprosthetic devices that provide hearing to deaf patients, although outcomes are highly variable even with prolonged training and use. The central auditory system must process cochlear implant signals, but it is unclear how neural circuits adapt—or fail to adapt—to such inputs. The knowledge of these mechanisms is required for development of next-generation neuroprosthetics that interface with existing neural circuits and enable synaptic plasticity to improve perceptual outcomes. Here, we describe a new system for cochlear implant insertion, stimulation, and behavioral training in rats. Animals were first ensured to have significant hearing loss via physiological and behavioral criteria. We developed a surgical approach for multichannel (2- or 8-channel) array insertion, comparable with implantation procedures and depth in humans. Peripheral and cortical responses to stimulation were used to program the implant objectively. Animals fitted with implants learned to use them for an auditory-dependent task that assesses frequency detection and recognition in a background of environmentally and self-generated noise and ceased responding appropriately to sounds when the implant was temporarily inactivated. This physiologically calibrated and behaviorally validated system provides a powerful opportunity to study the neural basis of neuroprosthetic device use and plasticity.


2013 ◽  
Vol 22 (4) ◽  
pp. 591-603 ◽  
Author(s):  
David J. Ertmer ◽  
Jongmin Jung ◽  
Diana True Kloiber

PurposeSpeech-like utterances containing rapidly combined consonants and vowels eventually dominate the prelinguistic and early word productions of typically developing (TD) toddlers. It seems reasonable to expect a similar phenomenon in young recipients of cochlear implants (CIs). The authors of this study sought to determine the number of months of robust hearing experience needed to achieve a majority of speech-like utterances in both of these groups.MethodSpeech samples were recorded from CI recipients at 3-month intervals during the first 2 years of CI experience, and from TD children at time points between 6 and 24 months of age. Speech-like utterances were operationally defined as those belonging to the basic canonical syllables (BCS) or advanced forms (AF) levels of the Consolidated Stark Assessment of Early Vocal Development—Revised (Ertmer, Young, & Nathani, 2007).ResultsOn average, the CI group achieved a majority of speech-like utterances after 12 months of robust hearing experience and the TD group after 18 months. The CI group produced greater percentages of speech-like utterances at each interval until 24 months, when both groups approximated 80%.ConclusionAuditory deprivation did not limit progress in vocal development as young CI recipients showed more-rapid-than-typical speech development during the first 2 years of device use. Implications for the infraphonological model of speech development are considered.


2002 ◽  
Vol 33 (3) ◽  
pp. 162-171 ◽  
Author(s):  
Holly F. B. Teagle ◽  
Jan A. Moore

School-based speech, language, and hearing professionals are instrumental in the provision of rehabilitative, consultative, and support services for children with cochlear implants. This article reviews current candidacy requirements as well as factors that are considered when a child is evaluated for a cochlear implant. Following implantation, school professionals play a pivotal role in providing an appropriate educational program that should include auditory training and the integration of listening into the child’s daily routine. The article presents procedures for maintaining and troubleshooting the device, and suggestions for establishing routines for device use and for improving the listening environment for children in classrooms.


2019 ◽  
Vol 28 (4) ◽  
pp. 986-992 ◽  
Author(s):  
Lisa R. Park ◽  
Erika B. Gagnon ◽  
Erin Thompson ◽  
Kevin D. Brown

Purpose The aims of this study were to (a) determine a metric for describing full-time use (FTU), (b) establish whether age at FTU in children with cochlear implants (CIs) predicts language at 3 years of age better than age at surgery, and (c) describe the extent of FTU and length of time it took to establish FTU in this population. Method This retrospective analysis examined receptive and expressive language outcomes at 3 years of age for 40 children with CIs. Multiple linear regression analyses were run with age at surgery and age at FTU as predictor variables. FTU definitions included 8 hr of device use and 80% of average waking hours for a typically developing child. Descriptive statistics were used to describe the establishment and degree of FTU. Results Although 8 hr of daily wear is typically considered FTU in the literature, the 80% hearing hours percentage metric accounts for more variability in outcomes. For both receptive and expressive language, age at FTU was found to be a better predictor of outcomes than age at surgery. It took an average of 17 months for children in this cohort to establish FTU, and only 52.5% reached this milestone by the time they were 3 years old. Conclusions Children with normal hearing can access spoken language whenever they are awake, and the amount of time young children are awake increases with age. A metric that incorporates the percentage of time that children with CIs have access to sound as compared to their same-aged peers with normal hearing accounts for more variability in outcomes than using an arbitrary number of hours. Although early FTU is not possible without surgery occurring at a young age, device placement does not guarantee use and does not predict language outcomes as well as age at FTU.


Author(s):  
C Thomas ◽  
J Westwood ◽  
G F Butt

Abstract Background YouTube is increasingly used as a source of healthcare information. This study evaluated the quality of videos on YouTube about cochlear implants. Methods YouTube was searched using the phrase ‘cochlear implant’. The first 60 results were screened by two independent reviewers. A modified Discern tool was used to evaluate the quality of each video. Results Forty-seven videos were analysed. The mean overall Discern score was 2.0 out of 5.0. Videos scored higher for describing positive elements such as the benefits of a cochlear implant (mean score of 3.4) and scored lower for negative elements such as the risks of cochlear implant surgery (mean score of 1.3). Conclusion The quality of information regarding cochlear implant surgery on YouTube is highly variable. These results demonstrated a bias towards the positive attributes of cochlear implants, with little mention of the risks or uncertainty involved. Although videos may be useful as supplementary information, critical elements required to make an informed decision are lacking. This is of particular importance when patients are considering surgery.


Author(s):  
A. Molisz ◽  
A. Zarowski ◽  
E. Cardinael ◽  
A. Vermeiren ◽  
T. Theunen ◽  
...  

Abstract Background Fitting cochlear implants in babies and noncooperative patients is cumbersome and time consuming. Therefore, objective parameters have been sought in order to predict the subjective threshold (T) and maximum comfort (C) levels. Measurements of the electrically evoked compound action potentials (ECAPs) have been widely used for this purpose, yet the correlation between these objective measures and the subjective T/C levels is weak to moderate. Purpose This article aims (1) to evaluate correlations between the subjective parameters of the fitting maps such as thresholds (T level) and maximum comfort levels (C level), the impedance of the electrode contacts, and the ECAP thresholds, and (2) to compare the value of the electrode impedances and the ECAP measures for prediction of the T/C levels. Research Design Case review study in a quaternary otologic referral center. Study Sample Ninety-eight consecutive CI patients were enrolled. The average age of the patients was 49 years. All patients were users of the Nucleus 24RECA (Freedom, Contour Advance-of-Stylet electrode) cochlear implant. Data Collection and Analysis Data on impedance of the electrode contacts and the behavioral T/C levels at the first fitting session (2–5 weeks after surgery) and at the 5th fitting session (4–6 months after surgery) have been retrospectively collected in 98 consecutive CI patients. Additionally, the intraoperative impedance values and the ECAP thresholds (tNRT) have been recorded. Results Impedances of electrode contacts show significant strong negative correlations with the stabilized T/C levels at 4 to 6 months after implantation and are an important predictor for the behavioral T/C levels. They can explain R 2 = 28 to 41% of the variability of the behavioral T/C levels. In multiple regression analysis electrode contact impedances can explain twice as much of the variability of the stabilized T/C levels than the tNRT values. The electrode impedances together with the tNRT values are able to explain R 2 = 37 to 40% of the global variability of the T/C levels while the tNRT thresholds solely are able to explain only R 2 = 5 to 14% of the T/C levels variability. Conclusion Impedances of electrode contacts correlate strongly with the stabilized behavioral T/C levels and may be used as an objective measure for fitting of cochlear implants.


2016 ◽  
Vol 21 (03) ◽  
pp. 206-212 ◽  
Author(s):  
Grace Ciscare ◽  
Erika Mantello ◽  
Carla Fortunato-Queiroz ◽  
Miguel Hyppolito ◽  
Ana Reis

Introduction A cochlear implant in adolescent patients with pre-lingual deafness is still a debatable issue. Objective The objective of this study is to analyze and compare the development of auditory speech perception in children with pre-lingual auditory impairment submitted to cochlear implant, in different age groups in the first year after implantation. Method This is a retrospective study, documentary research, in which we analyzed 78 reports of children with severe bilateral sensorineural hearing loss, unilateral cochlear implant users of both sexes. They were divided into three groups: G1, 22 infants aged less than 42 months; G2, 28 infants aged between 43 to 83 months; and G3, 28 older than 84 months. We collected medical record data to characterize the patients, auditory thresholds with cochlear implants, assessment of speech perception, and auditory skills. Results There was no statistical difference in the association of the results among groups G1, G2, and G3 with sex, caregiver education level, city of residence, and speech perception level. There was a moderate correlation between age and hearing aid use time, age and cochlear implants use time. There was a strong correlation between age and the age cochlear implants was performed, hearing aid use time and age CI was performed. Conclusion There was no statistical difference in the speech perception in relation to the patient's age when cochlear implant was performed. There were statistically significant differences for the variables of auditory deprivation time between G3 - G1 and G2 - G1 and hearing aid use time between G3 - G2 and G3 - G1.


1996 ◽  
Vol 39 (3) ◽  
pp. 604-610 ◽  
Author(s):  
Nancy Tye-Murray ◽  
Linda Spencer ◽  
Elizabeth Gilbert Bedia ◽  
George Woodworth

Twenty children who have worn a Cochlear Corporation cochlear implant for an average of 33.6 months participated in a device-on/off experiment. They spoke 14 monosyllabic words three times each after having not worn their cochlear implant speech processors for several hours. They then spoke the same speech sample again with their cochlear implants turned on. The utterances were phonetically transcribed by speech-language pathologists. On average, no difference between speaking conditions on indices of vowel height, vowel place, initial consonant place, initial consonant voicing, or final consonant voicing was found. Comparisons based on a narrow transcription of the speech samples revealed no difference between the two speaking conditions. Children who were more intelligible were no more likely to show a degradation in their speech production in the device-off condition than children who were less intelligible. In the device-on condition, children sometimes nasalized their vowels and inappropriately aspirated their consonants. Their tendency to nasalize vowels and aspirate initial consonants might reflect an attempt to increase proprioceptive feedback, which would provide them with a greater awareness of their speaking behavior.


2018 ◽  
Author(s):  
Eline Verschueren ◽  
Ben Somers ◽  
Tom Francart

ABSTRACTThe speech envelope is essential for speech understanding and can be reconstructed from the electroencephalogram (EEG) recorded while listening to running speech. This so-called neural envelope tracking has been shown to relate to speech understanding in normal hearing listeners, but has barely been investigated in persons wearing cochlear implants (CI). We investigated the relation between speech understanding and neural envelope tracking in CI users.EEG was recorded in 8 CI users while they listened to a story. Speech understanding was varied by changing the intensity of the presented speech. The speech envelope was reconstructed from the EEG using a linear decoder and then correlated with the envelope of the speech stimulus as a measure of neural envelope tracking which was compared to actual speech understanding.This study showed that neural envelope tracking increased with increasing speech understanding in every participant. Furthermore behaviorally measured speech understanding was correlated with participant specific neural envelope tracking results indicating the potential of neural envelope tracking as an objective measure of speech understanding in CI users. This could enable objective and automatic fitting of CIs and pave the way towards closed-loop CIs that adjust continuously and automatically to individual CI users.


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