Use of Functional Near-Infrared Spectroscopy to Predict and Measure Cochlear Implant Outcomes: A Scoping Review.

Outcomes following cochlear implantation vary widely for both adults and children, and behavioral tests are currently relied upon to assess this. However, these behavioral tests rely on subjective judgements that can be unreliable, particularly for infants and young children. The addition of an objective test of outcome following cochlear implantation is therefore desirable. The aim of this scoping review was to comprehensively catalogue the evidence for the potential of functional near infrared spectroscopy (fNIRS) to be used as a tool to objectively predict and measure cochlear implant outcomes. A scoping review of the literature was conducted following the PRISMA extension for scoping review framework. Searches were conducted in the MEDLINE, EMBASE, PubMed, CINAHL, SCOPUS, and Web of Science electronic databases, with a hand search conducted in Google Scholar. Key terms relating to near infrared spectroscopy and cochlear implants were used to identify relevant publications. Eight records met the criteria for inclusion. Seven records reported on adult populations, with five records only including post-lingually deaf individuals and two including both pre- and post-lingually deaf individuals. Studies were either longitudinal or cross-sectional, and all studies compared fNIRS measurements with receptive speech outcomes. This review identified and collated key work in this field. The homogeneity of the populations studied so far identifies key gaps for future research, including the use of fNIRS in infants. By mapping the literature on this important topic, this review contributes knowledge towards the improvement of outcomes following cochlear implantation.

Evaluating cortical responses to speech in children: A functional near-infrared spectroscopy (fNIRS) study.

Functional neuroimaging of speech processing has both research and clinical potential. This work is facilitating an ever-increasing understanding of the complex neural mechanisms involved in the processing of speech. Neural correlates of speech understanding also have potential clinical value, especially for infants and children, in whom behavioural assessments can be unreliable. Such measures would not only benefit normally hearing children experiencing speech and language delay, but also hearing impaired children with and without hearing devices. In the current study, we examined cortical correlates of speech intelligibility in normally hearing paediatric listeners. Cortical responses were measured using functional near-infrared spectroscopy (fNIRS), a non-invasive neuroimaging technique that is fully compatible with hearing devices, including cochlear implants. In nineteen normally hearing children (aged 6 - 13 years) we measured activity in temporal and frontal cortex bilaterally whilst participants listened to both clear- and noise-vocoded sentences targeting four levels of speech intelligibility. Cortical activation in superior temporal and inferior frontal cortex was generally stronger in the left hemisphere than in the right. Activation in left superior temporal cortex grew monotonically with increasing speech intelligibility. In the same region, we identified a trend towards greater activation on correctly vs. incorrectly perceived trials, suggesting a possible sensitivity to speech intelligibility per se, beyond sensitivity to changing acoustic properties across stimulation conditions. Outside superior temporal cortex, we identified other regions in which fNIRS responses varied with speech intelligibility. For example, channels overlying posterior middle temporal regions in the right hemisphere exhibited relative deactivation during sentence processing (compared to a silent baseline condition), with the amplitude of that deactivation being greater in more difficult listening conditions. This finding may represent sensitivity to components of the default mode network in lateral temporal regions, and hence effortful listening in normally hearing paediatric listeners. Our results indicate that fNIRS has the potential to provide an objective marker of speech intelligibility in normally hearing children. Should these results be found to apply to individuals experiencing language delay or to those listening through a hearing device, such as a cochlear implant, fNIRS may form the basis of a clinically useful measure of speech understanding.

Recommended Personal Protective Equipment for Cochlear Implant and Other Mastoid Surgery During the COVID-19 Era.

OBJECTIVES/HYPOTHESIS: The overall aim of this study was to evaluate personal protective equipment (PPE) that may facilitate the safe recommencement of cochlear implantation in the COVID-19 era, with the broader goal of minimizing the period of auditory deprivation in prelingually deaf children and reducing the risk of cochlear ossification in individuals following meningitis. METHODS: The study design comprised 1) an objective assessment of mastoid drilling-induced droplet spread conducted during simulated cochlear implant (CI) surgery and its mitigation via the use of a protective drape tent and 2) an evaluation of three PPE configurations by otologists while performing mastoid drilling on ex vivo temporal bones. The various PPE solutions were assessed in terms of their impact on communication, vital physiological parameters, visual acuity and fields, and acceptability to surgeons using a systematic risk-based approach. RESULTS: Droplet spread during simulated CI surgery extended over 2 m, a distance greater than previously reported. A drape tent significantly reduced droplet spread. The ensemble of a half-face mask and safety spoggles (foam lined safety goggles) had consistently superior performance across all aspects of clinical usability. All other PPE options were found to substantially restrict the visual field, making them unsafe for microsurgery. CONCLUSIONS: The results of this preclinical study indicate that the most viable solution to enable the safe conduct of CI and other mastoid surgery is a combination of a filtering facepiece (FFP3) mask or half-face respirator with safety spoggles as PPE. Prescription spoggles are an option for surgeons who need to wear corrective glasses to operate. A drape tent reduces droplet spread. A multicenter clinical trial to evaluate the effectiveness of PPE should be the next step toward safely performing CI surgery during the COVID-19 era. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:2693-2699, 2020.

Cortical correlates of speech intelligibility measured using functional near-infrared spectroscopy (fNIRS).

Functional neuroimaging has identified that the temporal, frontal and parietal cortex support core aspects of speech processing. An objective measure of speech intelligibility based on cortical activation in these brain regions would be extremely useful to speech communication and hearing device applications. In the current study, we used noise-vocoded speech to examine cortical correlates of speech intelligibility in normally-hearing listeners using functional near-infrared spectroscopy (fNIRS), a non-invasive, neuroimaging technique that is fully-compatible with hearing devices, including cochlear implants. In twenty-three normally-hearing adults we measured (1) activation in superior temporal, inferior frontal and inferior parietal cortex bilaterally and (2) behavioural speech intelligibility. Listeners heard noise-vocoded sentences targeting five equally spaced levels of intelligibility between 0 and 100% correct. Activation in superior temporal regions increased linearly with intelligibility. This relationship appears to have been driven in part by changing acoustic properties across stimulation conditions, rather than solely by intelligibility per se. Superior temporal activation was also predictive of individual differences in intelligibility in a challenging listening condition. Beyond superior temporal cortex, we identified regions in which activation varied non-linearly with intelligibility. For example, in left inferior frontal cortex, activation peaked in response to heavily degraded, yet still somewhat intelligible, speech. Activation in this region was linearly related to response time on a simultaneous behavioural task, suggesting it may contribute to decision making. Our results indicate that fNIRS has the potential to provide an objective measure of speech intelligibility in normally-hearing listeners. Should these results be found to apply similarly in the case of individuals listening through a cochlear implant, fNIRS would demonstrate potential for a clinically useful measure not only of speech intelligibility, but also of listening effort.

Surgical Management of the Drooling Child.

PURPOSE OF REVIEW: Our goal is to present the most up-to-date options in the surgical management of drooling in the paediatric population. While the clinical assessment of the drooling child and conservative management options are discussed, this review focuses on the most recent evidence for surgical interventions to treat drooling in children. RECENT FINDINGS: In terms of advances in the management of drooling, further experience and outcomes with the use of botulinum toxin injections is discussed. Moreover, the latest evidence-base for salivary duct ligation and relocation procedures are presented. Finally, the trans-oral approach to submandibular gland excision for the management of drooling may gain popularity through the aim of reducing surgical morbidity. SUMMARY: The drooling child should be managed with an evidence-based stepwise approach delivered by a multidisciplinary team (MDT). Children with normal neurological development should be treated conservatively through parental reassurance. There are numerous interventions available for the drooling child with impaired neuromuscular development. When conservative measures fail, treatment options include botulinum toxin injections and surgical procedures such as salivary duct ligation, salivary duct relocation and salivary gland excision. Management must be targeted to the individual needs and comorbidities of the child to maximise treatment outcomes.

Hold your horses: A comparison of human laryngomalacia with analogous equine airway pathology.

OBJECTIVES: Laryngomalacia is the most common cause of stridor in infants. Dynamic airway collapse is also a well-recognised entity in horses and an important cause of surgical veterinary intervention. We compare the aetiology, clinical features and management of human laryngomalacia with equine dynamic airway collapse. METHODS: A structured review of the PubMed, the Ovid Medline and the Cochrane Collaboration databases (Cochrane Central Register of Controlled Trials, Cochrane Database of Systemic Reviews). RESULTS: There are numerous equine conditions that cause dynamic airway collapse defined specifically by the anatomical structures involved. Axial Deviation of the Aryepiglottic Folds (ADAF) is the condition most clinically analogous to laryngomalacia in humans, and is likewise most prevalent in the immature equine airway. Both conditions are managed either conservatively, or if symptoms require it, with surgical intervention. The operative procedures performed for ADAF and laryngomalacia are technically comparable. CONCLUSION: Dynamic collapse of the equine larynx, especially ADAF, is clinically similar to human laryngomalacia, and both are treated in a similar fashion.

Pediatric septoplasy: a review of the literature.

OBJECTIVES: Controversy has surrounded the procedure of pediatric septoplasty since the 1950s due to concerns over an adverse effect on nasal and facial growth. However, more recent evidence has demonstrated that septoplasty can be safely performed without affecting nasal and facial development in the appropriately selected pediatric patient. The purpose of this article is to establish the impact of pediatric septoplasty on nasal and facial growth and review the clinical indications and evidence for timing of surgery according to the most recent literature. METHODS: A structured review of the PubMed, Ovid Medline and Cochrane Collaboration databases (Cochrane Central Register of Controlled Trials, Cochrane Database of Systemic Reviews) was undertaken, using the terms: pediatric, childhood, septoplasty, nasal septum, indications, nasal growth and facial growth. RESULTS: Three long term follow up studies using anthropometric measurements were identified which concluded that pediatric septoplasty does not interfere with normal nasal or facial development. A further similar study concluded that external septoplasty does not affect most aspects of nasal and facial growth, but may negatively influence growth of the nasal dorsum. Furthermore, one study demonstrated that a group of children with symptomatic uncorrected deviated nasal septum had a statistically significant increased occurrence of facial and dental anomalies compared with age and sex matched controls, therefore supporting a role for septoplasty. CONCLUSIONS: Evidence exists to support that pediatric septoplasty can be performed without affecting most aspects of nasal and facial growth. Furthermore, not performing or delaying septoplasty when indicated may adversely affect nasal and facial growth with compounding adverse effects in terms of deformity and asymmetry. Despite the majority advocating the timing of septal surgery to be 6 years and older, more clinical studies are required that may provide further evidence for correction of septal deviations in younger children, perhaps even at birth.