Structural connectivity changes in unilateral hearing loss.

Network connectivity, as mapped by the whole brain connectome, plays a crucial role in regulating auditory function. Auditory deprivation such as unilateral hearing loss might alter structural network connectivity; however, these potential alterations are poorly understood. Thirty-seven acoustic neuroma patients with unilateral hearing loss (19 left-sided and 18 right-sided) and 19 healthy controls underwent diffusion-weighted and T1-weighted imaging to assess edge strength, node strength, and global efficiency of the structural connectome. Edge strength was estimated by pair-wise normalized streamline density from tractography and connectomics. Node strength and global efficiency were calculated through graph theory analysis of the connectome. Pure-tone audiometry and word recognition scores were used to correlate the degree and duration of unilateral hearing loss with node strength and global efficiency. We demonstrate significantly stronger edge strength and node strength through the visual network, weaker edge strength and node strength in the somatomotor network, and stronger global efficiency in the unilateral hearing loss patients. No discernible correlations were observed between the degree and duration of unilateral hearing loss and the measures of node strength or global efficiency. These findings contribute to our understanding of the role of structural connectivity in hearing by facilitating visual network upregulation and somatomotor network downregulation after unilateral hearing loss.

Effects of the BalanCI on Working Memory and Balance in Children and Young Adults With Cochleovestibular Dysfunction.

OBJECTIVES: This study aimed to: (1) determine the interaction between cognitive load and balance in children and young adults with bilateral cochleovestibular dysfunction who use bilateral cochlear implants (CIs) and (2) determine the effect of an auditory balance prosthesis (the BalanCI) on this interaction. Many (20 to 70%) children with sensorineural hearing loss experience some degree of vestibular loss, leading to poorer balance. Poor balance could have effects on cognitive resource allocation which might be alleviated by the BalanCI as it translates head-referenced cues into electrical pulses delivered through the CI. It is hypothesized that children and young adults with cochleovestibular dysfunction will demonstrate greater dual-task costs than typically-developing children during dual balance-cognition tasks, and that BalanCI use will improve performance on these tasks. DESIGN: Study participants were 15 typically-developing children (control group: mean age ± SD = 13.6 ± 2.75 years, 6 females) and 10 children and young adults who use bilateral CIs and have vestibular dysfunction (CI-V group: mean age ± SD=20.6 ± 5.36 years, 7 females). Participants completed two working memory tasks (backward auditory verbal digit span task and backward visuospatial dot matrix task) during three balance conditions: seated, standing in tandem stance with the BalanCI off, and standing in tandem stance with the BalanCI on. Working memory performance was quantified as total number of correct trials achieved. Postural stability was quantified as translational and rotational path length of motion capture markers worn on the head, upper body, pelvis, and feet, normalized by trial time. RESULTS: Relative to the control group, children and young adults in the CI-V group exhibited poorer overall working memory across all balance conditions ( p = 0.03), poorer translational postural stability (larger translational path length) during both verbal and visuospatial working memory tasks ( p < 0.001), and poorer rotational stability (larger rotational path length) during the verbal working memory task ( p = 0.026). The CI-V group also exhibited poorer translational ( p = 0.004) and rotational ( p < 0.001) postural stability during the backward verbal digit span task than backward visuospatial dot matrix task; BalanCI use reduced this stability difference between verbal and visuospatial working memory tasks for translational stability overall ( p > 0.9), as well as for rotational stability during the maximum working memory span (highest load) participants achieved in each task ( p = 0.91). CONCLUSIONS: Balance and working memory were impaired in the CI-V group compared with the control group. The BalanCI offered subtle improvements in stability in the CI-V group during a backward verbal working memory task, without producing a negative effect on working memory outcomes. This study supports the feasibility of the BalanCI as a balance prosthesis for individuals with cochleovestibular impairments.

Importance of early objective auditory testing in the presentation of sudden sensorineural hearing loss in children.

BACKGROUND: Functional hearing loss can be due to an auditory manifestation of functional neurological disorder, previously known as conversion disorder. METHODS: This is a case series of 3 pediatric patients with a diagnosis of idiopathic SSNHL who ultimately were found to have functional neurological disorder. RESULTS: Average age was 12.7 years at presentation (range 10-14 years). All three patients underwent invasive interventions prior to their initial clinic visit. All patients demonstrated profound SNHL on behavioural audiogram, but normal otoacoustic emissions (OAE) and auditory brainstem response testing. With counselling, both patients demonstrated significant hearing improvement. CONCLUSIONS: Early use of OAE's in the workup of SSNHL can avoid unnecessary and potentially harmful therapies and expedite access to counselling services which may help lead to symptom resolution.

Longitudinal Effects of Simultaneous and Sequential Bilateral Cochlear Implantation on Cortical Auditory-Evoked Potentials Recorded at Cz in a Large Cohort of Children.

OBJECTIVES: Auditory development after bilateral cochlear implantation in children has been measured using source localization of multi-channel late latency responses. It is not clear, however, whether this development can be tracked using a more clinically feasible method of recording from one active recording electrode placed at mid-line center of the head (Cz). DESIGN: In this prospective cohort study, cortical auditory-evoked potential responses (CAEPs) were recorded from Cz referenced to each earlobe (Cz-CAEP) from 222 children with bilateral cochlear implant (CI); 128 (mean ± SD age: 2.78 ± 3.30 years) received both CIs in the same surgery (simultaneous group) and 94 (aged 7.72 ± 4.45 years) received a second CI after 4.21 ± 2.98 years of unilateral CI use. We sought to (1) identify cortical development over the first couple of years of bilateral CI use; (2) measure known asymmetries in auditory development between the CIs; and (3) detect the effects of bilateral rather than unilateral CI use. 4556 Cz-CAEPs were recorded across the cohort over 33.50 ± 7.67 months duration of bilateral CI use. Given concerns related to peak picking, amplitude areas were measured across two response time windows (50 to 199 ms and 200 to 400 ms). RESULTS: Results indicated that small response amplitudes occur at initial CI use and amplitudes increase in the negative or positive direction rapidly over the first months of CI use in both time windows. Asymmetries between Cz-CAEPs evoked by each CI were found in the sequential group and reduced with bilateral CI use, particularly in the first time window; these differences increased with longer inter-implant delay. Bilaterally evoked Cz-CAEPs were larger in amplitude than unilateral responses from either CI in the simultaneous group. In the sequential group, bilateral responses were similar to responses from the first implanted side but increased in relative amplitude with bilateral CI use. The Cz-CAEP measures were not able to predict asymmetries or bilateral benefits in speech perception measures. CONCLUSIONS: The Cz-CAEP was able to indicate cortical detection of CI input and showed gross morphological changes with bilateral CI use. Findings indicate Cz-CAEPs can be used to identify gross changes in auditory development in children with bilateral CIs, but they are less sensitive to tracking the remaining abnormalities that are measured by multi-channel CAEPs and speech perception testing.

Predicting Wrist Posture during Occupational Tasks Using Inertial Sensors and Convolutional Neural Networks.

Current methods for ergonomic assessment often use video-analysis to estimate wrist postures during occupational tasks. Wearable sensing and machine learning have the potential to automate this tedious task, and in doing so greatly extend the amount of data available to clinicians and researchers. A method of predicting wrist posture from inertial measurement units placed on the wrist and hand via a deep convolutional neural network has been developed. This study has quantified the accuracy and reliability of the postures predicted by this system relative to the gold standard of optoelectronic motion capture. Ten participants performed 3 different simulated occupational tasks on 2 occasions while wearing inertial measurement units on the hand and wrist. Data from the occupational task recordings were used to train a convolutional neural network classifier to estimate wrist posture in flexion/extension, and radial/ulnar deviation. The model was trained and tested in a leave-one-out cross validation format. Agreement between the proposed system and optoelectronic motion capture was 65% with κ = 0.41 in flexion/extension and 60% with κ = 0.48 in radial/ulnar deviation. The proposed system can predict wrist posture in flexion/extension and radial/ulnar deviation with accuracy and reliability congruent with published values for human estimators. This system can estimate wrist posture during occupational tasks in a small fraction of the time it takes a human to perform the same task. This offers opportunity to expand the capabilities of practitioners by eliminating the tedium of manual postural assessment.

Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents.

Unilateral auditory deprivation in early childhood can lead to cortical strengthening of inputs from the stimulated side, yet the impact of this on bilateral processing when inputs are later restored beyond an early sensitive period is unknown. To address this, we conducted a longitudinal study with 13 bilaterally profoundly deaf adolescents who received unilateral access to sound via a cochlear implant (CI) in their right ear in early childhood before receiving bilateral access to sound a decade later via a second CI in their left ear. Auditory-evoked cortical responses to unilateral and bilateral stimulation were measured repeatedly using electroencephalogram from 1 week to 14 months after activation of their second CI. Early cortical responses from the newly implanted ear and bilateral stimulation were atypically lateralized to the left ipsilateral auditory cortex. Duration of unilateral deafness predicted an unexpectedly stronger representation of inputs from the newly implanted, compared to the first implanted ear, in left auditory cortex. Significant initial reductions in responses were observed, yet a left-hemisphere bias and unequal weighting of inputs favoring the long-term deaf ear did not converge to a balanced state observed in the binaurally developed system. Bilateral response enhancement was significantly reduced in left auditory cortex suggesting deficits in ipsilateral response inhibition of new, dominant, inputs during bilateral processing. These findings paradoxically demonstrate the adaptive capacity of the adolescent auditory system beyond an early sensitive period for bilateral input, as well as restrictions on its potential to fully reverse cortical imbalances driven by long-term unilateral deafness.

Effects of Sequential Bilateral Cochlear Implantation in Children: Evidence from Speech-Evoked Cortical Potentials and Tests of Speech Perception.

INTRODUCTION: Benefits of bilateral cochlear implants (CI) may be compromised by delays to implantation of either ear. This study aimed to evaluate the effects of sequential bilateral CI use in children who received their first CI at young ages, using a clinical set-up. METHODS: One-channel cortical auditory evoked potentials and speech perception in quiet and noise were evoked at repeated times (0, 3, 6, 12 months of bilateral CI use) by unilateral and bilateral stimulation in 28 children with early-onset deafness. These children were unilaterally implanted before 3.69 years of age (mean ± SD of 1.98 ± 0.73 years) and received a second CI after 5.13 ± 2.37 years of unilateral CI use. Comparisons between unilaterally evoked responses were used to measure asymmetric function between the ears and comparisons between bilateral responses and each unilateral response were used to measure the bilateral benefit. RESULTS: Chronic bilateral CI promoted changes in cortical auditory responses and speech perception performance; however, large asymmetries were present between the two unilateral responses despite ongoing bilateral CI use. Persistent cortical differences between the two sides at 1 year of bilateral stimulation were predicted by increasing age at the first surgery and inter-implant delay. Larger asymmetries in speech perception occurred with longer inter-implant delays. Bilateral responses were more similar to the unilateral responses from the first rather than the second CI. CONCLUSION: These findings are consistent with the development of the aural preference syndrome and reinforce the importance of providing bilateral CIs simultaneously or sequentially with very short delays.

Vestibular Perceptual Thresholds in Older Adults With and Without Age-related Hearing Loss.

OBJECTIVES: Older adults with age-related hearing loss (ARHL) are at greater risk of falling and have greater mobility problems than older adults with normal hearing (NH). The underlying cause of these associations remains unclear. One possible reason is that age-related declines in the vestibular system could parallel those observed in the auditory system within the same individuals. Here, we compare the sensitivity of vestibular perceptual abilities (psychophysics), vestibular end-organ functioning (vestibular evoked myogenic potentials and video head impulse tests), and standing balance (posturography) in healthy older adults with and without ARHL. DESIGN: A total of 46 community-dwelling older adults, 23 with ARHL and 23 with NH, were passively translated in heave (up and down) and rotated in pitch (tilted forward and backward) in the dark using a motion platform. Using an adaptive staircase psychophysical procedure, participants' heave and pitch detection and discrimination thresholds were determined. In a posturography task, participants' center of pressure (COP) path length was measured as they stood on a forceplate with eyes open and closed, on firm and compliant surfaces, with and without sound suppression. Baseline motor, cognitive, and sensory functioning, including vestibular end-organ function, were measured. RESULTS: Individuals with ARHL were less sensitive at discriminating pitch movements compared to older adults with NH. Poorer self-reported hearing abilities were also associated with poorer pitch discrimination. In addition to pitch discrimination thresholds, lower pitch detection thresholds were significantly associated with hearing loss in the low-frequency range. Less stable standing balance was significantly associated with poorer vestibular perceptual sensitivity. DISCUSSION: These findings provide evidence for an association between ARHL and reduced vestibular perceptual sensitivity.

Accuracy of a Low-Cost 3D-Printed Wearable Goniometer for Measuring Wrist Motion.

Wrist motion provides an important metric for disease monitoring and occupational risk assessment. The collection of wrist kinematics in occupational or other real-world environments could augment traditional observational or video-analysis based assessment. We have developed a low-cost 3D printed wearable device, capable of being produced on consumer grade desktop 3D printers. Here we present a preliminary validation of the device against a gold standard optical motion capture system. Data were collected from 10 participants performing a static angle matching task while seated at a desk. The wearable device output was significantly correlated with the optical motion capture system yielding a coefficient of determination (R2) of 0.991 and 0.972 for flexion/extension (FE) and radial/ulnar deviation (RUD) respectively (p < 0.0001). Error was similarly low with a root mean squared error of 4.9° (FE) and 3.9° (RUD). Agreement between the two systems was quantified using Bland-Altman analysis, with bias and 95% limits of agreement of 3.1° ± 7.4° and -0.16° ± 7.7° for FE and RUD, respectively. These results compare favourably with current methods for occupational assessment, suggesting strong potential for field implementation.

Interhemispheric auditory connectivity requires normal access to sound in both ears during development.

Despite early bilateral cochlear implantation, children with congenital deafness do not develop accurate spatial hearing; we thus asked whether auditory brain networks are disrupted in these children. EEG responses were evoked unilaterally and bilaterally in 13 children with normal hearing and 16 children receiving bilateral cochlear implants simultaneously. Active cortical areas were estimated by the Time Restricted Artifact and Coherent source Suppression (TRACS) beamformer and connected cortical areas were identified by measuring coherence between source responses. A whole-brain analysis of theta band coherence revealed the strongest connections between the temporal areas in all conditions at early latencies. Stronger imaginary coherence in activity between the two auditory cortices to bilateral than unilateral input was found in children with normal hearing reflecting facilitation in the auditory network during bilateral hearing. The opposite effect, depressed coherence, was found during bilateral stimulation in children using cochlear implants. Children with cochlear implants also showed a unique auditory network in response to bilateral stimulation which was marked by increased connectivity between occipital and frontal areas. These findings suggest that cortical networks for sound processing are normally facilitated by bilateral input but are disrupted in children who hear through two independent cochlear implants. Efforts to improve hearing in children with congenital deafness must thus include corrections to potential mismatches in bilateral input to support brain development.

BalanCI: Head-Referenced Cochlear Implant Stimulation Improves Balance in Children with Bilateral Cochleovestibular Loss.

INTRODUCTION: To determine the impact of a head-referenced cochlear implant (CI) stimulation system, BalanCI, on balance and postural control in children with bilateral cochleovestibular loss (BCVL) who use bilateral CI. METHODS: Prospective, blinded case-control study. Balance and postural control testing occurred in two settings: (1) quiet clinical setting and (2) immersive realistic virtual environment (Challenging Environment Assessment Laboratory [CEAL], Toronto Rehabilitation Institute). Postural control was assessed in 16 and balance in 10 children with BCVL who use bilateral CI, along with 10 typically developing children. Children with neuromotor, cognitive, or visual deficits that would prevent them from performing the tests were excluded. Children wore the BalanCI, which is a head-mounted device that couples with their CIs through the audio port and provides head-referenced spatial information delivered via the intracochlear electrode array. Postural control was measured by center of pressure (COP) and time to fall using the WiiTM (Nintendo, WA, USA) Balance Board for feet and the BalanCI for head, during the administration of the Modified Clinical Test of Sensory Interaction in Balance (CTSIB-M). The COP of the head and feet were assessed for change by deviation, measured as root mean square around the COP (COP-RMS), rate of deviation (COP-RMS/duration), and rate of path length change from center (COP-velocity). Balance was assessed by the Bruininks-Oseretsky Test of Motor Proficiency 2, balance subtest (BOT-2), specifically, BOT-2 score as well as time to fall/fault. RESULTS: In the virtual environment, children demonstrated more stable balance when using BalanCI as measured by an improvement in BOT-2 scores. In a quiet clinical setting, the use of BalanCI led to improved postural control as demonstrated by significant reductions in COP-RMS and COP-velocity. With the use of BalanCI, the number of falls/faults was significantly reduced and time to fall increased. CONCLUSIONS: BalanCI is a simple and effective means of improving postural control and balance in children with BCVL who use bilateral CI. BalanCI could potentially improve the safety of these children, reduce the effort they expend maintaining balance and allow them to take part in more complex balance tasks where sensory information may be limited and/or noisy.

Can Differences in Early Hearing Development Be Distinguished by the LittlEARs Auditory Questionnaire?

OBJECTIVE: This study asks whether the LittlEARs Auditory Questionnaire (LEAQ), a caregiver measure, can differentiate between the early auditory development of children with bilateral cochlear implants (CIs), bilateral hearing aids (HAs), and children with Auditory Neuropathy Spectrum Disorder (ANSD) who wear CIs or HAs. The LEAQ is sensitive to impaired auditory development but has not previously been used to distinguish developmental changes between groups of children using different hearing technologies or with different types of hearing loss. DESIGN: We collected retrospective longitudinal LEAQ results from 43 children with HAs, 43 with CIs, and 18 with ANSD. The children with ANSD wore hearing technology. They were a similar age to the children without ANSD (23 months; SD = 15), while the CI group (14 months; SD = 8) was younger than the HA group (24 months; SD = 18) [F(2,98.48) = 3.4; p = 0.04]. The CI group often participated in their first LEAQ pretreatment. Participants completed between one and seven LEAQs. Scores ranged between zero and 35 (mean = 18.36). We conducted a linear mixed-effects analysis, which included age or time since device fitting, hearing type (HA, CI, or ANSD), and presence of a comorbidity as fixed effects. A secondary analysis assessed effects of device audibility, measured by the Speech Intelligibility Index or Articulation Index, and consistency of device use obtained from device datalogs. RESULTS: Children with CIs progressed faster than their peers with HAs or ANSD [χ2(8) = 24.51; p = 0.002]. However, within a subsample that included consistency of device use (ß7 = -0.20 ± 0.38, t = -0.52; ß8 = 0.93 ± 0.82, t = 1.13) and audibility (ß6 = -0.70 ± 1.45, t = -1.87; ß7 = 0.87 ± 0.89, t = 0.98), study group did not significantly influence rate of improvement on the LEAQ. In addition, children with developmental delays in all three study groups demonstrated significantly slower LEAQ score improvement [χ2(6) = 23.60; p < 0.001] and a trend toward decreased consistency of device use [F(1) = 3.31; p = 0.07]. As we expected, children in the CI and HA groups were more likely to achieve auditory skills indicated in early rather than later LEAQ questions. There was less variability in the responses of the ANSD group [CI: interquartile range (IQR) = 9; HA: IQR = 8; ANSD: IQR = 1]. There was no connection between LEAQ growth and speech perception outcomes in a subsample [r(6) = 0.42; p = 0.30]. CONCLUSIONS: The LEAQ is a useful tool for monitoring initial auditory development in very young children and can inform early treatment decisions.

Cochlear Implant Use Remains Consistent Over Time in Children With Single-Sided Deafness.

OBJECTIVES: To measure the acceptance of a cochlear implant by children with single-sided deafness (SSD) using datalogging technology in the cochlear implant processor. DESIGN: Datalogs from follow-up clinical audiology appointments for 23 children with SSD were extracted from their cochlear implant processors ranging from 1 to 8 visits (M = 3.74, SD = 1.79). The number of hours the cochlear implant was in use per day, the number of times the coil disconnected from the internal device, and the percentage of daily cochlear implant use in different auditory environments were collected from the datalogs. Linear mixed-effects regressions were used to analyze the relationship between age, hearing experience, cochlear implant use, and coil-offs per day. Nonlinear regressions were conducted to evaluate cochlear implant use in different environments. RESULTS: Children with SSD wore their cochlear implants for 6.22 (SD = 2.81; range = 0.0004 to 14.74) hours per day on average. No significant change in cochlear implant use was seen as the children grew older or gained more hearing experience. As hearing experience increased, the number of coil-offs per day was reduced. Preschoolers spent more time in "music" and "speech" and less time in "noise" and "quiet" than older and younger children while older children spent more time in "speech-in-noise." CONCLUSIONS: Children with SSD consistently wear their cochlear implants. However, the auditory environments to which they are exposed vary over time. Regular cochlear implant use by this population suggests that it does not detract from a normal-hearing ear and that children with SSD appreciate access to bilateral input.

"Aural Patching" After Bilateral Cochlear Implantation Is Challenging for Children With Prior Long-Term Unilateral Implant Experience.

OBJECTIVES: To assess the use of "aural patching" as a strategy to potentially reduce the known persistence of aural preference in children receiving bilateral cochlear implants (CIs) with long inter-implant delays by removing the first device to increase stimulation to the second implanted side. DESIGN: Children/adolescents who received a second CI at 12.8 ± 3.5 years of age after 9.4 ± 2.9 years of unilateral CI use were asked to remove their first CI for regular periods daily (aural patching). Their compliance was monitored, and asymmetries in speech perception were measured at the end of the study period. RESULTS: Partial adherence to aural patching over the first few months of bilateral hearing use markedly declined with time. As expected, the group demonstrated asymmetries in speech perception that were not significantly affected by the limited aural patching. CONCLUSIONS: The aural patching protocol was a challenge to maintain for most children and families studied, reflecting both the expected aural preference for the first implanted ear and their challenges to reverse it.

Binaural hearing is impaired in children with hearing loss who use bilateral hearing aids.

This paper asked whether children fitted with bilateral hearing aids (BHA) develop normal perception of binaural cues which are the basis of spatial hearing. Data from children with BHA (n = 26, age = 12.6 ± 2.84 years) were compared to data from a control group (n = 12, age = 12.36 ± 2.83 years). Stimuli were 250 Hz click-trains of 36 ms and a 40 ms consonant-vowel /da/ at 1 Hz presented through ER3A insert-earphones unilaterally or bilaterally. Bilateral stimuli were presented at different interaural level difference (ILD) and interaural timing difference (ITD) conditions. Participants indicated whether the sound came from the left or right side (lateralization) or whether one sound or two could be heard (binaural fusion). BHA children lateralized ILDs similarly to the control group but had impaired lateralization of ITDs. Longer response times relative to controls suggest that lateralization of ITDs was challenging for children with BHA. Most, but not all, of the BHA group were able to fuse click and speech sounds similarly to controls. Those unable to fuse showed particularly poor ITD lateralization. Results suggest that ITD perception is abnormal in children using BHAs, suggesting persistent effects of hearing loss that are not remediated by present clinical rehabilitation protocols.

3D strain in native medial meniscus is comparable to medial meniscus allograft transplant.

PURPOSE: Injury or degeneration of the meniscus has been associated with the development of osteoarthritis of the knee joint. Meniscal allograft transplant (MAT) has been shown to reduce pain and restore function in patients who remain symptomatic following meniscectomy. The purpose of this study is to evaluate and compare the three-dimensional (3D) strain in native medial menisci compared to allograft-transplanted medial menisci in both the loaded and unloaded states. METHODS: Ten human cadaveric knees underwent medial MAT, utilizing soft-tissue anterior and posterior root fixation via transosseous sutures tied over an anterolateral proximal tibial cortical bone bridge. The joint was imaged first in the non-loaded state, then was positioned at 5° of flexion and loaded to 1× body weight (650 ± 160 N) during MR image acquisition. Anatomical landmarks were chosen from each image to create a tibial coordinate system, which were then input into a custom-written program (Matlab R2014a) to calculate the 3D strain from the unloaded and loaded marker positions. Six independent strains were obtained: three principal strains and three shearing strains. RESULTS: No statistically significant difference was found between the middle and posterior strains in the native knee compared to the meniscus allograft. This would suggest that soft-tissue fixation of meniscal allografts results in similar time zero principal and shear strains in comparison to the native meniscus. CONCLUSION: These results suggest that time zero MAT performs in a similar manner to the native meniscus. Optimizing MAT strain behavior may lead to potential improvements in its chondroprotective effect.

Peripheral fixation of meniscal allograft does not reduce coronal extrusion under physiological load.

PURPOSE: Meniscal graft extrusion is a concern following meniscal allograft transplantation (MAT). MAT surgical techniques continue to evolve in an effort to reduce extrusion; however, improvements remain difficult to measure in vivo. A novel MRI-compatible in vitro loading device capable of applying physiologically relevant loads has been developed, allowing for the measurement of extrusion under a variety of controllable conditions. The objective of this study was to compare maximal medial MAT extrusion (1) with and (2) without an additional peripheral third point of fixation on the tibial plateau. METHODS: Twelve human cadaveric knees underwent medial MAT, utilizing soft tissue anterior and posterior root fixation via transosseous suture, with a third transosseous suture tied over a button providing peripheral fixation on the tibial plateau. The joint was positioned at 5 degrees of flexion and loaded to 1 × body weight (647.7 ± 159.0 N) during MR image acquisition, with and without peripheral fixation. The joint was then positioned at 30 degrees of flexion and the process was repeated. Maximal coronal extrusion was measured. RESULTS: An increase in maximal coronal meniscal extrusion was noted between the unloaded and loaded states. At 30 degrees of flexion, with the addition of a peripheral fixation point, a statistically significant difference in absolute extrusion (p = 0.02) and relative percent extrusion (p = 0.04) between the unloaded and loaded state was found. The addition of a peripheral fixation suture resulted in an overall mean percent difference of - 2.49% (SD 14.1; 95% CI - 11.95, 6.97; n.s.) in extrusion at 5 degrees of flexion and a mean percent difference of - 0.95% (SD 7.3; 95% CI - 5.62, 3.71; n.s.) in extrusion at 30 degrees of flexion. These differences were not statistically significant. CONCLUSION: These results suggest that the addition of a peripheral anchor in medial MAT does not reduce the amount of maximal coronal extrusion and, therefore, may not confer any clinical benefit. Surgical techniques utilized to reduce MAT extrusion need further investigation to understand if the added technical difficulty and potential expense is warranted.

Cortical Representation of Interaural Time Difference Is Impaired by Deafness in Development: Evidence from Children with Early Long-term Access to Sound through Bilateral Cochlear Implants Provided Simultaneously.

Accurate use of interaural time differences (ITDs) for spatial hearing may require access to bilateral auditory input during sensitive periods in human development. Providing bilateral cochlear implants (CIs) simultaneously promotes symmetrical development of bilateral auditory pathways but does not support normal ITD sensitivity. Thus, although binaural interactions are established by bilateral CIs in the auditory brainstem, potential deficits in cortical processing of ITDs remain. Cortical ITD processing in children with simultaneous bilateral CIs and normal hearing with similar time-in-sound was explored in the present study. Cortical activity evoked by bilateral stimuli with varying ITDs (0, ±0.4, ±1 ms) was recorded using multichannel electroencephalography. Source analyses indicated dominant activity in the right auditory cortex in both groups but limited ITD processing in children with bilateral CIs. In normal-hearing children, adult-like processing patterns were found underlying the immature P1 (∼100 ms) response peak with reduced activity in the auditory cortex ipsilateral to the leading ITD. Further, the left cortex showed a stronger preference than the right cortex for stimuli leading from the contralateral hemifield. By contrast, children with CIs demonstrated reduced ITD-related changes in both auditory cortices. Decreased parieto-occipital activity, possibly involved in spatial processing, was also revealed in children with CIs. Thus, simultaneous bilateral implantation in young children maintains right cortical dominance during binaural processing but does not fully overcome effects of deafness using present CI devices. Protection of bilateral pathways through simultaneous implantation might be capitalized for ITD processing with signal processing advances, which more consistently represent binaural timing cues.SIGNIFICANCE STATEMENT Multichannel electroencephalography demonstrated impairment of binaural processing in children who are deaf despite early access to bilateral auditory input by first finding that foundations for binaural hearing are normally established during early stages of cortical development. Although 4- to 7-year-old children with normal hearing had immature cortical responses, adult patterns in cortical coding of binaural timing cues were measured. Second, children receiving two cochlear implants in the same surgery maintained normal-like input from both ears, but this did not support significant effects of binaural timing cues in either auditory cortex. Deficits in parieto-occiptal areas further suggested impairment in spatial processing. Results indicate that cochlear implants working independently in each ear do not fully overcome deafness-related binaural processing deficits, even after long-term experience.

Cortical hemispheric asymmetries are present at young ages and further develop into adolescence.

Specialization of the auditory cortices for pure tone listening may develop with age. In adults, the right hemisphere dominates when listening to pure tones and music; we thus hypothesized that (a) asymmetric function between auditory cortices increases with age and (b) this development is specific to tonal rather than broadband/non-tonal stimuli. Cortical responses to tone-bursts and broadband click-trains were recorded by multichannel electroencephalography in young children (5.1 ± 0.8 years old) and adolescents (15.2 ± 1.7 years old) with normal hearing. Peak dipole moments indicating activity strength in right and left auditory cortices were calculated using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer. Monaural click-trains and tone-bursts in young children evoked a dominant response in the contralateral right cortex by left ear stimulation and, similarly, a contralateral left cortex response to click-trains in the right ear. Responses to tone-bursts in the right ear were more bilateral. In adolescents, peak activity dominated in the right cortex in most conditions (tone-bursts from either ear and to clicks from the left ear). Bilateral activity was evoked by right ear click stimulation. Thus, right hemispheric specialization for monaural tonal stimuli begins in children as young as 5 years of age and becomes more prominent by adolescence. These changes were marked by consistent dipole moments in the right auditory cortex with age in contrast to decreases in dipole activity in all other stimulus conditions. Together, the findings reveal increasingly asymmetric function for the two auditory cortices, potentially to support greater cortical specialization with development into adolescence.

Public Health Response to an Avian Influenza A(H7N8) Virus Outbreak in Commercial Turkey Flocks - Indiana, 2016.

In January 2016, highly pathogenic avian influenza (HPAI) A(H7N8) virus and low pathogenicity avian influenza (LPAI) A(H7N8) virus were detected in commercial turkey flocks in Dubois County, Indiana. The Indiana State Department of Health (ISDH) and the Dubois County Health Department (DCHD) coordinated the public health response to this outbreak, which was the first detection of HPAI A(H7N8) in any species (1). This response was the first to fully implement unpublished public health monitoring procedures for HPAI responders that were developed by the U.S. Department of Agriculture (USDA) and CDC in 2015 (Sonja Olsen, CDC, personal communication, October 2017). No cases of zoonotic avian influenza infection in humans were detected during the outbreak.