Leveraging Technology for Vestibular Assessment and Rehabilitation in the Operational Environment: A Scoping Review.

INTRODUCTION: The vestibular system, essential for gaze and postural stability, can be damaged by threats on the battlefield. Technology can aid in vestibular assessment and rehabilitation; however, not all devices are conducive to the delivery of healthcare in an austere setting. This scoping review aimed to examine the literature for technologies that can be utilized for vestibular assessment and rehabilitation in operational environments. MATERIALS AND METHODS: A comprehensive search of PubMed was performed. Articles were included if they related to central or peripheral vestibular disorders, addressed assessment or rehabilitation, leveraged technology, and were written in English. Articles were excluded if they discussed health conditions other than vestibular disorders, focused on devices or techniques not conducive to the operational environment, or were written in a language other than English. RESULTS: Our search strategy yielded 32 articles: 8 articles met our inclusion and exclusion criteria whereas the other 24 articles were rejected. DISCUSSION: There is untapped potential for leveraging technology for vestibular assessment and rehabilitation in the operational environment. Few studies were found in the peer-reviewed literature that described the application of technology to improve the identification of central and/or peripheral vestibular system impairments; triage of acutely injured patients; diagnosis; delivery and monitoring of rehabilitation; and determination of readiness for return to duty. CONCLUSIONS: This scoping review highlighted technology for vestibular assessment and rehabilitation feasible for use in an austere setting. Such technology may be leveraged for prevention; monitoring exposure to mechanisms of injury; vestibular-ocular motor evaluation; assessment, treatment, and monitoring of rehabilitation progress; and return-to-duty determination after vestibular injury. FUTURE DIRECTIONS: The future of vestibular assessment and rehabilitation may be shaped by austere manufacturing and 3D printing; artificial intelligence; drug delivery in combination with vestibular implantation; organ-on-chip and organoids; cell and gene therapy; and bioprinting.

Department of Defense Medical Examination Review Board Audiogram Screening Comparative Analysis.

INTRODUCTION: The Department of Defense Medical Examination Review Board (DoDMERB) plays a pivotal role in the assessment of medical fitness for aspiring military officers. A crucial component of this process is the screening audiogram, designed to evaluate hearing capabilities. However, recent observations of high disqualification rates following screening audiograms led to concerns about their accuracy. MATERIALS AND METHODS: This quality improvement project, conducted between 2017 and 2019, aimed to assess the concordance between screening audiograms and reference-standard audiometry, as well as to investigate the relationship between disqualification status and hearing thresholds at different frequencies. A sample of 134 candidates, drawn from various locations across the United States, was analyzed. RESULTS: Results revealed that the screening audiogram mean thresholds were twice that of the reference-standard audiogram, particularly in the lower frequencies. Additionally, we found that 84% of candidates were incorrectly disqualified by the screening exam when followed up by the reference-standard. Overall, Bland-Altman analysis revealed significant disagreement between these two tests. This discrepancy prompted a fundamental policy shift in 2020, where candidates who fail screening audiograms now automatically undergo reference-standard audiometry before any disqualification decision. This policy change reflects the commitment of DoDMERB to refining the medical screening process. It reduces the burden on candidates, provides a more comprehensive assessment, and ensures that qualified individuals are not erroneously disqualified.In addition to policy changes, this quality improvement project explored potential courses of action to enhance the screening audiogram process. Among these, improving contract specifications for testing facilities to minimize ambient noise emerged as the most practical and cost-effective approach. CONCLUSION: In conclusion, the project underscores the importance of refining medical screening processes to accurately assess candidates' qualifications while retaining the utility of screening audiograms. These efforts not only benefit aspiring military officers but also contribute to maintaining the high standards required for military service.

The Case Against Stapedectomy as a Core Competency for General Practice: A Study of Care Patterns in the Department of Defense.

OBJECTIVE: Stapedectomy remains a key indicator case reportable to the Accreditation Council of Graduate Medical Education despite the decline in the incidence of otosclerosis over the last half century. This study compared the rates of stapedectomy performed by otolaryngologists at academic and nonacademic centers. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral academic centers, nonacademic centers, and civilian purchased-care across the Department of Defense between 2015 and 2020. PATIENTS: Department of Defense beneficiaries with otosclerosis near a military treatment facility with an otolaryngologist. INTERVENTIONS: Stapedectomy (Current Procedural Terminology codes 69,660, 69,661, and 69,662). MAIN OUTCOME MEASURES: Number of stapedectomies performed by setting. RESULTS: From 2015 to 2020, 426 stapedectomies were performed at or near a military treatment facility with an otolaryngologist (274 directly by military otolaryngologists, 152 by community providers). Military providers performed 94% of stapedectomies at or near military academic centers, versus only 30% at or near nonacademic centers ( p < 0.0001). Among the 60 stapedectomies performed at nonacademic centers, only 30 were performed by general otolaryngologists (7% of all stapedectomies performed; 11% of procedures by military providers) while the rest were performed by fellowship-trained otologist or neurotologist. CONCLUSIONS: Low stapes surgical volume by military general otolaryngologists reinforces recent epidemiologic trends and suggests that few general otolaryngologists graduate residency with sufficient competency to pursue independently performing stapedectomy or have difficulty maintaining competency after graduation.

Noise-Induced Hearing Loss Treatment: Systematic Review and Meta-analysis.

OBJECTIVE: To determine the efficacy of steroid and hyperbaric oxygen therapy (HBOT) in the setting of acute noise-induced hearing loss. METHODS: Systematic review and meta-analysis of noise-induced hearing loss treatment studies that reported on patients who (1) reported individual frequencies up to 8,000 Hz with mean and SDs; (2) were treated only with steroids ± HBOT; and (3) sustained acute acoustic trauma. The Newcastle-Ottawa Scale was used to assess risk of bias across cohorts. Data sources were Embase, Web of Science, Cochrane Databases (via Ovid EBM Reviews), and PubMed. RESULTS: Four studies were of retrospective cohorts and one of a prospective cohort. Only one study examined blast acoustic trauma, and the remaining four examined gunfire acoustic trauma. This meta-analysis used a random-effects model for pure tone average (PTA) (0.5, 1, and 2 kHz) and "high-frequency" PTA (HPTA) (4, 6, and 8 kHz) for the five studies included. Steroid therapy demonstrated a 6.55-dB (95% CI, 0.08-13.17 dB) PTA (n = 55) improvement and a 9.02-dB (95% CI, 1.45-16.59 dB) HPTA (n = 71) improvement. Steroid with HBOT demonstrated a 7.00-dB (95% CI, 0.84-13.17 dB) PTA (n = 133) improvement and a 12.41-dB (95% CI, 3.97-20.86 dB) HPTA (n = 150) improvement. According to our statistical analysis of the pooled studies' heterogeneity, there was moderate inconsistency in the cross-study results of both treatment groups. CONCLUSION: Steroids with or without HBOT appear to improve both low and high hearing thresholds following acoustic trauma. Future studies will require inclusion of control groups, precise definition of acoustic trauma intensity and duration, and genetic polymorphisms.

Guideline Adherence and Hearing Outcomes of Sudden Sensorineural Hearing Loss in the Military Health System.

INTRODUCTION: The American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guideline (CPG) proposes several treatment recommendations regarding sudden sensorineural hearing loss (SSNHL). The treatments for this disorder have been controversial and remain varied. We sought to determine CPG adherence and hearing outcomes of SSNHL within the Military Health System (MHS). MATERIALS AND METHODS: This was a retrospective case series with chart review of the MHS's electronic medical record. Patients with SSNHL (n = 112) were treated between March 1, 2012 and September 30, 2015. Clinical improvement was defined as a 20-dB improvement in pure tone averages or a 20% increase in word recognition scores. RESULTS: Oral steroids were used in 63 (56%) patients, intratympanic (IT) steroids were utilized in 11 (10%) patients, and combination therapy was used in 38 (34%) patients. Average pure tone averages improvements with oral steroids, IT steroids, and combination therapy were 31.2 dB (95% CI, 24.4-38.0), 13.4 dB (95% CI, 0.4-29.6), and 17.3 dB (95% CI, 9.32-25.3), respectively. Average word recognition scores improvements with oral steroids, IT steroids, and combination therapy were 29.64% (95% CI, 19.5-39.7), 14.43% (95% CI, -8.32 to 45.3), and 18.48% (95% CI, 5.48-31.5), respectively. Clinical improvements with oral steroids, IT steroids, and combination therapy were 65, 46, and 50%, respectively. CONCLUSION: The MHS is uniquely positioned to evaluate adherence to CPGs on a national and international level given the robust and standardized electronic medical record. Areas identified for improvement include more timely initiation of treatment, standardization of IT steroid dosing, more accurate coding for diagnosis and treatment, and standardization of audiology evaluation.

Self-directed down-regulation of auditory cortex activity mediated by real-time fMRI neurofeedback augments attentional processes, resting cerebral perfusion, and auditory activation.

In this work, we investigated the use of real-time functional magnetic resonance imaging (fMRI) with neurofeedback training (NFT) to teach volitional down-regulation of the auditory cortex (AC) using directed attention strategies as there is a growing interest in the application of fMRI-NFT to treat neurologic disorders. Healthy participants were separated into two groups: the experimental group received real feedback regarding activity in the AC; the control group was supplied sham feedback yoked from a random participant in the experimental group and matched for fMRI-NFT experience. Each participant underwent five fMRI-NFT sessions. Each session contained 2 neurofeedback runs where participants completed alternating blocks of "rest" and "lower" conditions while viewing a continuously-updated bar representing AC activation and listening to continuous noise. Average AC deactivation was extracted from each closed-loop neuromodulation run and used to quantify the control over AC (AC control), which was found to significantly increase across training in the experimental group. Additionally, behavioral testing was completed outside of the MRI on sessions 1 and 5 consisting of a subjective questionnaire to assess attentional control and two quantitative tests of attention. No significant changes in behavior were observed; however, there was a significant correlation between changes in AC control and attentional control. Also, in a neural assessment before and after fMRI-NFT, AC activity in response to continuous noise stimulation was found to significantly decrease across training while changes in AC resting perfusion were found to be significantly greater in the experimental group. These results may be useful in formulating effective therapies outside of the MRI, specifically for chronic tinnitus which is often characterized by hyperactivity of the primary auditory cortex and altered attentional processes. Furthermore, the modulation of attention may be useful in developing therapies for other disorders such as chronic pain.

Aural Blast Injury/Acoustic Trauma and Hearing Loss.

Hearing is a critical sense to military performance. The ability to detect, identify, and localize sounds, the ability to maintain spatial awareness on the battlefield and the awareness to control one's own noise production can be vital to troop's stealth, survivability, and lethality. Hazardous noise is an environmental public health threat encountered in training at war, and in many off-duty activities. The risk to hearing and the resultant damage from any of these hazardous exposures is generally invisible, insidious and cumulative. Regardless of the source of injury, hearing loss degrades the sensor that integrates Service Members with their environment, provides for unity of effort, and ensures command and control.Acoustic trauma-induced hear loss and tinnitus are the two most prevalent disabilities in veterans, with over 765,000 cases in the Gulf War era alone. To counter this threat, it is necessary to push for early identification and early intervention through a trusted surveillance system. Success will require advocacy, education, and encouragement of self-reporting for evaluation following symptomatic noise exposures. This Clinical Practice Guideline (CPG) is a step to ensure the hearing health, readiness, protection, and care of Service Members. This will in turn optimize troop performance and minimize injury risk and mishap.

Sudden Sensorineural Hearing Loss in the Department of Defense.

Objective The American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guideline (CPG) proposes recommendations regarding sudden sensorineural hearing loss (SSNHL). SSNHL is managed by primary care, emergency medicine, and otolaryngology providers in the Department of Defense (DoD). However, their adherence to this CPG is unknown. We sought to determine provider compliance and identify areas for improvement. Study Design Case series with chart review. Setting DoD's electronic medical record. Subjects and Methods Patients with SSNHL (N = 204) were treated between March 1, 2012, and September 30, 2015. Time from onset of symptoms to evaluation by primary care, emergency department, audiology, and otolaryngology providers and treatments were analyzed. Results The average interval from onset of symptoms to evaluation by a primary care or emergency department provider was 4.86 days (95% CI, 3.46-6.26). Time from presentation to ear, nose, and throat and audiologic evaluation was 15.26 days (95% CI, 12.34-18.20) and 14.16 days (95% CI, 11.31-17.01), respectively. Diagnostic workup included magnetic resonance imaging (n = 150, 73.5%), computed tomography (n = 28, 13.7%), and laboratory testing (n = 50, 24.5%). Oral steroids were used in 137 (67.2%) patients, with 78.8% treated with the recommended dose. Intratympanic steroids were utilized in 65 (31.9%) patients, with variable dosing. Conclusion The DoD is uniquely positioned to evaluate adherence to CPGs on national and international levels given the robust and standardized electronic medical record. Areas of improvement include timely identification of SSNHL with rapid referral to ear, nose, and throat and audiology providers; minimizing unnecessary imaging, laboratory testing, and medications; and correct dosing of oral and intratympanic steroids.

Vestibular evoked myogenic potentials in young children: test parameters and normative data.

OBJECTIVE: The vestibular evoked myogenic potential (VEMP) is a test of the vestibulocollic reflex that has been extensively studied in adults. Much is known about the normal values in adults as well as their changes with age. In children, the expected test values and their possible changes in development have not yet been described nor has the feasibility of reliable testing in this group. The aim of this prospective study is to accumulate normative data and to verify the viability of testing in young children. The study focused on optimal test parameters, reproducibility, and subject compliance in a pediatric population. METHODS: Thirty normal-hearing children (60 ears) ages 3 to 11 completed VEMP testing and audiograms for analysis. VEMP testing was performed with alternating clicks at three intensities (80-, 85-, and 90-dB normalized hearing level) using averaged, unrectified electromyograms recorded by surface electrode on the sternocleidomastoid muscle ipsilateral to the stimulus. VEMP latencies, amplitude, compliance, and length of testing were recorded for each patient, as well as their feedback on the testing session. The subjects were divided into four age groups for analysis. RESULTS: All but one of the subjects attempting VEMP testing was able to finish. Of 30 children completing VEMP tests, bilateral reflexes were recorded for all subjects with symmetric responses in 28 of 30 subjects (93%). The mean peak latencies (+/- standard deviation [SD]) of pI and nII were 11.3 msec (1.3 ms) and 17.6 msec (1.4 ms), respectively. The mean pI-nII amplitude (+/- SD) was 122 muV (68 muV). There was a significantly shorter nII mean peak latency of group I (ages 3-5) left ear in comparison to other groups, with an absolute shorter mean latency nII in the right ear of group I (not significant). Average test time was 15 minutes with two researchers testing, and subjects were highly compliant. CONCLUSIONS: VEMP is a well-tolerated test for screening vestibular function in young children, performed with minimal test time and reproducible results. Mean latencies in this study suggested a shorter initial negative peak (nII) than in adult studies, consistent with prolongation seen in previous research on the effects of age. Ninety-decibel normalized hearing level clicks were adequate for uniform response rates. Expected latency and amplitude values in single-channel VEMP-unrectified electromyograms were established. This is the first study describing expected latencies and optimal testing parameters in children.

Comparison of facial nerve function results after translabyrinthine and retrosigmoid approach in medium-sized tumors.

OBJECTIVE: To compare postoperative facial nerve function results according to surgical approach. STUDY DESIGN: Retrospective case review study. SETTING: All surgical procedures were conducted in collaboration with a neurosurgery team in teaching hospitals with an academic affiliation. PATIENTS: Patients with medium to large vestibular schwannomas, with the tumor size ranging from 2 to 3 cm. Ninety-eight patients were identified from an "Acoustic Neuroma Database" (date range of search, 1983-2000). MAIN OUTCOME MEASURES: The House-Brackmann scale was used for grading facial function in the immediate postoperative period and 1 year after. Guidelines of the American Academy of Otolaryngology-Head and Neck Surgery were used for classification of hearing preservation. RESULTS: Of the 98 patients, 17 were operated on through a retrosigmoid approach and 81 through the translabyrinthine route. The mean +/- SD ages of these 2 groups of patients were 46 +/- 13 and 51 +/- 14 years, respectively; mean +/- SD tumor sizes were 2.5 +/- 0.27 and 2.6 +/- 0.28 cm, respectively. One year after tumor removal via retrosigmoid approach, 10 (59%) of the 17 patients had good (grade I-II) facial functions and 2 (12%) had poor (grade V-VI) function. In the translabyrinthine group, 54 (68%) of 79 patients (2 patients had subtotal total tumor removal) had good facial nerve function at the end of the 1-year follow-up, and 13 (17%) continued to have poor facial function. The difference between these groups was not statistically significant (P>.05). Hearing was preserved in 4 (24%) of the 17 patients in the retrosigmoid group. CONCLUSION: Although the translabyrinthine approach may offer better long-term facial function compared with the retrosigmoid approach in patients with medium-sized tumors, the difference between these 2 groups was not significant enough to favor one approach over the other.

Long-term results of small fenestra stapedectomy compared with large fenestra technique.

OBJECTIVES/HYPOTHESIS: A comparison is made of the postoperative long-term hearing results of small fenestra stapedectomy versus large fenestra techniques. Several reports in the literature favor improved hearing results in small fenestra stapedectomy compared with large fenestration and/or total stapedectomy. METHODS: A retrospective review of 34 patients who had stapedectomy performed by the same surgeon between 1982 and 1992. All patients have been followed for up to 10 years postoperatively. RESULTS: In 18 ears of 17 patients, surgery was performed with small fenestra technique, and 17 ears of 17 patients had total stapedectomy or posterior-half fenestration. After small fenestra stapedectomy, initial average air-bone gap at 500, 1000, and 2000 Hz was 9 dB hearing loss. Hearing thresholds at 4000 Hz deteriorated to 4% over the study period. Speech reception thresholds declined 15%. After total or posterior-half stapedectomy the average air-bone gap at 500, 1000, and 2000 Hz was 5 dB hearing loss. Hearing thresholds at 4000 Hz deteriorated 8% and 18% for the small fenestra and large fenestra groups, respectively, over time. Statistically, there was no difference in hearing deterioration rate between these two groups. CONCLUSIONS: An experienced surgeon can obtain excellent results using either large or small fenestra technique for otosclerosis. After initial successful closure of the air-bone gaps at all measured frequencies, hearing thresholds over the study period were stable for both groups.

Translabyrinthine approach for the management of large and giant vestibular schwannomas.

BACKGROUND: The removal of large vestibular schwannomas through the translabyrinthine approach is still controversial. MATERIALS AND METHODS: A retrospective review was performed of 81 patients (58 men and 23 women) with vestibular schwannomas 3 cm or greater, who underwent tumor removal via the translabyrinthine approach between 1985 and 2000. The mean tumor size was 3.7 +/- 0.81 cm, and the mean age of the patients was 47 +/- 16.1 years. The largest tumor was 6 cm. All surgical procedures were performed in collaboration with a neurosurgery team. RESULTS: Total tumor removal was accomplished in 77 cases (95.1%). The facial nerve was preserved anatomically in 69 (85.2%) of the patients. In 4 patients, divided nerves were repaired by primary anastomosis. Facial nerve function was assessed immediately after surgery and 1 year or more after discharge. Good function (House-Brackmann facial nerve Grade I or II) was present in 45% of patients and acceptable function (Grades I-IV) in 80% of patients 1 year after resection of the tumor. Cerebrospinal fluid leakage occurred in 12 patients (17%), meningitis developed in 3 patients (4%), and 1 patient experienced a stroke immediately after surgery. There were no deaths caused by surgery in this series. CONCLUSION: The translabyrinthine approach offers an excellent anatomical view of the cerebellopontine angle and a direct approach to the tumor with functional preservation of the facial nerve. Total removal is accomplished in most cases, with minimum incidence of morbidity and no incidence of mortality.