Hearing and Vestibular Loss with Misuse of Opioids and Illicit Drugs: A Review of the Literature.

BACKGROUND: The purpose of this review was to summarize the literature regarding the effects of opioids and illicit drugs on the auditory and vestibular systems. METHODS: Data were sourced from published papers reporting hearing loss (HL) and/or vestibular loss (VL) following misuse or overdose of opioids or illicit drugs. Most papers consisted of retrospective single-case reports, with few retrospective reviews or prospective cohort studies. Search terms included variations of HL, VL, opioids, and illicit drugs. Search results yielded 51 articles published between 1976 and 2021. A total of 44 articles were reviewed after excluding studies that were not available in English (n = 3), only described acute effects in healthy cohorts (n = 3) or only described general health aspects in a group on methadone maintenance (n = 1). RESULTS: Sixteen studies reported ototoxicity from illicit drugs, 27 from prescription opioids, and 1 was unspecified. This review shows that HL associated with amphetamines and cocaine was typically sudden, bilateral, and temporary. HL from cocaine/crack and heroin often presented with greatest losses in the mid-frequency range. HL associated with opioids was typically sudden, bilateral, moderately severe to profound, and in most cases permanent. The literature is sparse regarding VL from illicit drugs and opioids. CONCLUSION: Practitioners who see patients for sudden or rapidly progressive HL or VL with no apparent cause should inquire about misuse of illicit drugs and opioids, particularly when the HL does not respond to steroid treatment.

Age Effects of Bone Conduction Vibration Vestibular-evoked Myogenic Potentials (VEMPs) Using B81 and Impulse Hammer Stimuli.

OBJECTIVE: Recently developed, the Radioear B81 bone oscillator allows for higher bone conduction vibration output; however, normative data are lacking regarding its use in vestibular-evoked myogenic potential (VEMP) testing. The purpose of this study was to examine the effect of age on cervical and ocular VEMP (c- and oVEMP) responses using the B81 and to compare with air conduction stimuli (ACS) and impulse hammer (IH) VEMP response characteristics. DESIGN: c- and oVEMP were completed with ACS, B81, and IH stimuli in healthy participants (age range = 10 to 87 years, n = 85). RESULTS: Regardless of stimulus type, c- and oVEMP amplitudes and response rates decreased with age. For cVEMP response rates, ACS performed better or equal to B81, which was superior to the IH. For cVEMP corrected amplitude, ACS had significantly higher amplitudes compared with B81 and IH. There was no difference in cVEMP corrected amplitude between B81 and IH. For oVEMP, response rates were comparable between stimuli with the largest disparity in response rates occurring in the oldest groups where IH outperformed both ACS and B81. For oVEMP amplitude, IH had significantly higher amplitudes compared with B81 and ACS. There was no difference in oVEMP amplitude between B81 and ACS. CONCLUSIONS: Age significantly affected c- and oVEMP amplitudes regardless of stimulus type (ACS, B81, IH). All stimuli are appropriate for eliciting c- and oVEMP in the young individuals. While ACS resulted in higher cVEMP corrected amplitudes, either ACS or B81 are appropriate for older individuals. However, for oVEMPs, higher response rates and larger amplitudes were noted for IH followed by B81 and ACS. Overall, the B81 performed well across the lifespan for c- and oVEMPs and may be a reasonable bone conduction vibration option for patients with absent ACS VEMPs, but at this time is not recommended as a replacement to ACS.

Bone Conduction Vibration Vestibular Evoked Myogenic Potential (VEMP) Testing: Reliability in Children, Adolescents, and Young Adults.

OBJECTIVES: Bone conduction vibration (BCV) vestibular evoked myogenic potentials (VEMP) are clinically desirable in children for multiple reasons. However, no accepted standard exists for stimulus type and the reliability of BCV devices has not been investigated in children. The objective of the current study was to determine which BCV VEMP method (B-71, impulse hammer, or Mini-shaker) yields the highest response rates and reliability in a group of adults, adolescents, and children. It was hypothesized that the Mini-shaker would yield the highest response rates and reliability because it provides frequency specificity, higher output levels without distortion, and the most consistent force output as compared to the impulse hammer and B-71. DESIGN: Participants included 10 child (ages 5 to 10), 11 adolescent (ages 11 to 18), and 11 young adult (ages 23 to 39) normal controls. Cervical VEMP (cVEMP) and ocular VEMP (oVEMP) were measured in response to suprathreshold air-conducted, 500 Hz tone bursts and 3 types of BCV (B-71, impulse hammer, and Mini-shaker) across 2 test sessions to assess reliability. RESULTS: For cVEMP, response rates were 100% for all methods in all groups with the exception of the adult group in response to the impulse hammer (95%). For oVEMP, response rates varied by group and BCV method. For cVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the impulse hammer, and in children using the B-71. For oVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the Mini-shaker or impulse hammer, and in children using the impulse hammer. Age positively correlated with air-conducted oVEMP amplitude, but not cVEMP amplitude or cVEMP corrected amplitude. Age negatively correlated with all BCV VEMP amplitudes with the exception of cVEMP corrected amplitude in response to the Mini-shaker. CONCLUSIONS: All BCV methods resulted in consistent cVEMP responses (response rates 95 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) for all groups. Similarly, all BCV methods resulted in consistent oVEMP responses (89 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) except for the B-71 in adults.

Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children, Adolescents, and Young Adults: Thresholds, Frequency Tuning, and Effects of Sound Exposure.

OBJECTIVES: Pediatric vestibular evaluations incorporate cervical and ocular vestibular evoked myogenic potential (c- and oVEMP, respectively) testing; however, in children, c- and oVEMP thresholds have been minimally investigated and frequency tuning is unknown. Children are also at risk for unsafe sound exposure secondary to VEMP. While it is unknown if VEMP threshold testing leads to cochlear changes, it is possible that this risk increases due to the increased number of trials needed to obtain a threshold. Obtaining VEMP thresholds at various frequencies in children provides further information for pediatric normative VEMP data. Assessing for cochlear changes after VEMP threshold testing would provide information on the safety of threshold VEMP testing in children. The objectives of this study were to (1) characterize c- and oVEMP thresholds in children, adolescents, and young adults with normal hearing using 500 and 750 Hz tone burst (TB) stimuli, (2) compare frequency tuning of 500 and 750 Hz TB, and (3) assess whether cochlear changes exist after VEMP threshold testing. It is hypothesized that children, adolescents, and young adults would not show age-related changes to the vestibular system. Therefore, reliable VEMP thresholds would be seen below maximum acoustical stimulation levels (e.g., <125 dB SPL) and frequency tuning will be similar for 500 and 750 Hz TB stimuli. DESIGN: Ten children (age 4-9), 10 adolescents (age 10-19), and 10 young adults (age 20-29) with normal hearing and tympanometry participated. All subjects received c- and oVEMP testing at maximum stimulation and threshold. To address frequency tuning, but not exceed recommended sound exposure allowance, subjects received a 500 Hz TB stimulus in one ear and a 750 Hz TB stimulus in the other ear. Subjects completed tympanometry pre-VEMP, and audiometric threshold testing, distortion product otoacoustic emission testing, and subjective questionnaire pre- and post-VEMP to study the effect of VEMP exposure on cochlear function for each stimulus frequency. RESULTS: (1) cVEMP thresholds were determined for both stimulus frequencies for children (500 Hz = 106 dB SPL; 750 Hz = 106 dB SPL), adolescents (500 Hz = 107.5 dB SPL; 750 Hz = 109.5 dB SPL), and young adults (500 Hz = 111.5 dB SPL; 750 Hz = 112 dB SPL). oVEMP thresholds were also obtained in response to both stimulus frequencies for children (500 Hz = 111.1 dB SPL; 750 Hz = 112.2 dB SPL), adolescents (500 Hz = 112.5 dB SPL; 750 Hz = 114.5 dB SPL), and young adults (500 Hz = 116 dB SPL; 750 Hz = 117 dB SPL). Similar thresholds were found between groups except for children who had significantly lower thresholds compared with adults for cVEMP (500 Hz: p = 0.002; 750 Hz: p = 0.004) and oVEMP (500 Hz: p = 0.01; 750 Hz: p = 0.02). In addition, equivalent ear-canal volume and VEMP thresholds were linearly correlated. (2) There was no significant effect of stimulus frequency on VEMP response rates, latencies, peak to peak amplitudes, or thresholds, suggesting similar frequency tuning for 500 and 750 Hz. (3) There were no significant effects of VEMP threshold testing on cochlear function for either stimulus frequency. CONCLUSIONS: Children, adolescents, and young adults show VEMP thresholds below high stimulation levels and had similar frequency tuning between 500 and 750 Hz. Use of 750 Hz could be regarded as the safer stimuli due to its shorter duration and thus reduced sound exposure. Children with smaller ear-canal volume had present responses at maximum stimulation and lower thresholds, suggesting that VEMP testing could be initiated at lower acoustic levels to minimize sound exposure and optimize testing.

Effects of High Sound Exposure During Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children and Young Adults.

OBJECTIVES: Vestibular evoked myogenic potential (VEMP) testing is increasingly utilized in pediatric vestibular evaluations due to its diagnostic capability to identify otolith dysfunction and feasibility of testing. However, there is evidence demonstrating that the high-intensity stimulation level required to elicit a reliable VEMP response causes acoustic trauma in adults. Despite utility of VEMP testing in children, similar findings are unknown. It is hypothesized that increased sound exposure may exist in children because differences in ear-canal volume (ECV) compared with adults, and the effect of stimulus parameters (e.g., signal duration and intensity) will alter exposure levels delivered to a child's ear. The objectives of this study are to (1) measure peak to peak equivalent sound pressure levels (peSPL) in children with normal hearing (CNH) and young adults with normal hearing (ANH) using high-intensity VEMP stimuli, (2) determine the effect of ECV on peSPL and calculate a safe exposure level for VEMP, and (3) assess whether cochlear changes exist after VEMP exposure. DESIGN: This was a 2-phase approach. Fifteen CNH and 12 ANH participated in phase I. Equivalent ECV was measured. In 1 ear, peSPL was recorded for 5 seconds at 105 to 125 dB SPL, in 5-dB increments for 500- and 750-Hz tone bursts. Recorded peSPL values (accounting for stimulus duration) were then used to calculate safe sound energy exposure values for VEMP testing using the 132-dB recommended energy allowance from the 2003 European Union Guidelines. Fifteen CNH and 10 ANH received cervical and ocular VEMP testing in 1 ear in phase II. Subjects completed tympanometry, pre- and postaudiometric threshold testing, distortion product otoacoustic emissions, and questionnaire addressing subjective otologic symptoms to study the effect of VEMP exposure on cochlear function. RESULTS: (1) In response to high-intensity stimulation levels (e.g., 125 dB SPL), CNH had significantly higher peSPL measurements and smaller ECVs compared with ANH. (2) A significant linear relationship between equivalent ECV (as measured by diagnostic tympanometry) and peSPL exists and has an effect on total sound energy exposure level; based on data from phase I, 120 dB SPL was determined to be an acoustically safe stimulation level for testing in children. (3) Using calculated safe stimulation level for VEMP testing, there were no significant effect of VEMP exposure on cochlear function (as measured by audiometric thresholds, distortion product otoacoustic emission amplitude levels, or subjective symptoms) in CNH and ANH. CONCLUSIONS: peSPL sound recordings in children's ears are significantly higher (~3 dB) than that in adults in response to high-intensity VEMP stimuli that are commonly practiced. Equivalent ECV contributes to peSPL delivered to the ear during VEMP testing and should be considered to determine safe acoustic VEMP stimulus parameters; children with smaller ECVs are at risk for unsafe sound exposure during routine VEMP testing, and stimuli should not exceed 120 dB SPL. Using 120 dB SPL stimulus level for children during VEMP testing yields no change to cochlear function and reliable VEMP responses.

Vestibular-Evoked Myogenic Potential Outcomes Associated with Pediatric Sports-Related Concussion.

OBJECTIVES/HYPOTHESIS: To 1) characterize vestibular-evoked myogenic potential responses in children and young adults with sports-related concussion (SRC) histories as compared with a normal healthy control group, and 2) correlate VEMP characteristics to SRC/sport history outcomes. STUDY DESIGN: Prospective cohort study. METHODS: Seventy-six children and young adults with and without a history of SRC received cervical and ocular VEMP testing using a 500 Hz tone burst air conduction stimuli. VEMP response parameters (response rates, peak latencies, and peak-to-peak amplitudes) were assessed. Other clinical vestibular measures were performed. In the SRC group, sport history outcomes including number of SRC sustained over a lifetime, years of playing contact sports, and length of time playing contact sports were collected via in-person questionnaire. RESULTS: Children and young adults with SRC had significantly reduced oVEMP responses and peak-to-peak amplitudes and greater amplitude response asymmetries between left and right ear. There was no effect of group on cVEMP findings. A greater frequency of SRCs sustained throughout a lifetime, a greater number of contact sports played, and a longer duration of playing a contact sport correlated with significantly poorer VEMP response characteristics. CONCLUSIONS: Our results suggest that SRC and repeated subclinical head impact events have an effect on oVEMP outcomes. SRC may affect the utricle, superior vestibular nerve, and/or brainstem-mediated vestibular-ocular-reflex pathway. The prevalence of post-concussion-related dizziness is becoming increasingly common in a pediatric-otology clinic, thus performing VEMP testing in youth post-SRC provides an objective, noninvasive, and cost-effective method for monitoring the effects of sports-related impact on the vestibular system and related neural pathways. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:436-442, 2022.

Vestibular Evoked Myogenic Potential (VEMP) Test-retest Reliability in Children.

OBJECTIVE: Vestibular evoked myogenic potentials (VEMPs) are short-latency muscle potentials measured from the neck (cervical VEMP; cVEMP) or under the eyes (ocular VEMP; oVEMP), which provide information regarding function of the saccule and utricle, respectively. VEMPs are reliable when performed in adults; however, reliability of VEMPs in children is unknown. Therefore, the purpose of the study was to determine the test-retest reliability of c- and oVEMP testing in normal control children. STUDY DESIGN: Prospective. SETTING: Hospital. PATIENTS: Ten adults, 14 adolescent children and 13 young children with normal hearing. INTERVENTIONS: c- and oVEMP testing were completed across two test sessions in response to air-conduction 500 Hz tone-burst and impulse hammer stimuli. Additionally, oVEMP was completed using eyes-open and eyes-closed conditions. MAIN OUTCOME MEASURES: Intraclass correlation coefficients were calculated to determine the reliability of c- and oVEMP outcomes. RESULTS: When using air-conduction stimuli, c- and oVEMP amplitudes are reliable across test sessions in normal control children and adults. With impulse hammer stimuli, cVEMP amplitudes showed high reliability; however, oVEMP amplitudes showed low reliability in both eyes-open and eyes-closed conditions. Comparison between eyes-open and eyes-closed oVEMP conditions revealed shorter latencies and higher peak-to-peak amplitudes in the eyes-open condition. CONCLUSIONS: In this small cohort of normal control children, cVEMPs are reliable using air-conduction and impulse hammer stimuli and oVEMPs are reliable using air-conduction stimuli in the eyes-open condition. oVEMP in eyes-closed conditions were less reliable compared with eyes-open conditions and resulted in a large number of absent responses.

Optimization of Cervical and Ocular Vestibular Evoked Myogenic Potential Testing Using an Impulse Hammer in Adults, Adolescents, and Children.

OBJECTIVE: To characterize cervical and ocular vestibular evoked myogenic potential (c- and oVEMP) responses using an impulse hammer (IH) in adults and pediatrics at standardized force levels and evaluate: the relationship of force level on VEMP amplitude, sternocleidomastoid (SCM) contraction on cVEMP amplitude, required number of tap stimuli, and subject comfort. Using these data, optimal testing parameters were selected. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Seventy-eight healthy adults, adolescents, and children with no hearing or vestibular deficits. INTERVENTIONS: All subjects received c- and oVEMP testing using IH and 500 Hz tone burst air conduction stimuli. Adults received hard, medium, and soft force levels. Adolescents and children received medium and soft force levels. A comfort questionnaire was administered pre- and post-testing. MAIN OUTCOME MEASURES: IH VEMP response parameters (response rates, latency, cVEMP pre-stimulus SCM Electromyography [EMG], and peak-to-peak amplitude) were assessed per force level. Subjective reporting for patient comfort was also assessed. RESULTS: VEMP response rates ranged from 92 to 100%. Force had a linear relationship with VEMP amplitude. SCM contraction had a linear relationship with raw cVEMP amplitude; however, dissipated with amplitude normalization. Force level did not impact the number of taps needed. A minimum peak force of 15 to 20 N, accounting for SCM contraction, and using a lower EMG monitoring limit for cVEMP is recommended to elicit reliable responses. CONCLUSIONS: Overall, IH VEMP is appropriate and comfortable to use in adults and pediatrics and can be useful when an air conduction stimulus is contraindicated or not preferred.

Quantitative Vestibular Function Testing in the Pediatric Population.

Quantitative tests of vestibular function include the caloric test, cervical and ocular vestibular evoked myogenic potential (VEMP), rotary chair, and head impulse test, either at the bedside or utilizing video head impulse test (vHIT). The purpose of this article is to provide an overview of how to perform these tests in children, including which tests are recommended based on the child's age and any modifications or considerations that can be made. A variety of clinical measures have been recommended as screening measures for vestibular loss, which will be reviewed. Symptom questionnaires designed to assess the functional impact of dizziness and vestibular loss in children will also be discussed. If a child complains of dizziness or if vestibular loss is suspected (either by case history or positive screening measure), vestibular function testing is warranted. For vestibular function testing, children aged 0 to 2 years typically receive rotary chair, cervical VEMP, and vHIT if a remote system is available. For children aged 3 to 7 years, vHIT, cervical VEMP, and ocular VEMP are completed, and for children aged 8+ years, vHIT, caloric testing if vHIT is normal, and cervical and ocular VEMP are completed. For all children, modifications to testing can be made, as needed.

Impact of Target Distance, Target Size, and Visual Acuity on the Video Head Impulse Test.

The video head impulse test (vHIT) assesses the vestibulo-ocular reflex. Few have evaluated whether environmental factors or visual acuity influence the vHIT. The purpose of this study was to evaluate the influence of target distance, target size, and visual acuity on vHIT outcomes. Thirty-eight normal controls and 8 subjects with vestibular loss (VL) participated. vHIT was completed at 3 distances and with 3 target sizes. Normal controls were subdivided on the basis of visual acuity. Corrective saccade frequency, corrective saccade amplitude, and gain were tabulated. In the normal control group, there were no significant effects of target size or visual acuity for any vHIT outcome parameters; however, gain increased as target distance decreased. The VL group demonstrated higher corrective saccade frequency and amplitude and lower gain as compared with controls. In conclusion, decreasing target distance increases gain for normal controls but not subjects with VL. Preliminarily, visual acuity does not affect vHIT outcomes.

Importance of an Interprofessional Team Approach in Achieving Improved Management of the Dizzy Patient.

BACKGROUND: Because of its multifaceted nature, dizziness is difficult for clinicians to diagnose and manage independently. Current treatment trends suggest that patients are often referred to the otolaryngologist for intervention despite having a nonotologic disorder. Additionally, many individuals with atypical presentations are often misdiagnosed and spend a significant amount of time waiting for consultation by the otolaryngologist. Few studies have alluded that implementation of an interprofessional team approach in the diagnosis and management of the dizzy patient can improve clinical decision-making. However, to the authors' knowledge, there is no information specifically quantifying the outcomes and potential benefits of using an interprofessional balance care team approach. PURPOSE: To compare dizziness diagnoses trends and referral practices with and without the use of an interprofessional management approach within a university healthcare system. RESEARCH DESIGN: Over the course of a 3-yr period, a retrospective review of the diagnosis and management of dizziness was performed with and without implementation of an interprofessional team. To observe potential differences, year 3 incorporated the interprofessional management approach while years 1-2 did not. The two periods were then compared to each other. STUDY SAMPLE: A total of 134 patients referred to a university hearing clinic for a vestibular and balance function evaluation. DATA COLLECTION AND ANALYSIS: Diagnoses and management trends were examined with descriptive statistics (percentages and frequencies). Fisher's exact tests, analysis of contingency tables, were conducted to evaluate the influence of interprofessional management on dizziness diagnoses and treatment patterns. RESULTS: Results demonstrated that before implementation of an interprofessional team approach, (1) referring clinicians used unspecific dizziness diagnosis codes (e.g., dizziness and giddiness), (2) a low number of patients with dizziness were referred for balance function testing, (3) diagnoses remained unspecific following the balance function assessment, and (4) the most frequently occurring vestibular diagnoses were unilateral vestibular hypofunction and benign paroxysmal positional vertigo. Following the use of an interprofessional management approach, it was determined that (1) disease-specific diagnoses increased, (2) patients with dizziness were referred for balance function testing mainly by otolaryngologists, (3) dizziness was considered to be multifaceted for a greater number of patients, (4) a larger percentage of patients were referred to a specialist other than the otolaryngologist as a result of their diagnosis, and (5) patients reported reduction or resolution of their symptoms. CONCLUSIONS: An interprofessional management approach for the dizzy patient can lead to more specific diagnoses and provide alternative referral pathways to other health-care professionals (e.g., audiologists, physical therapists, and pharmacists) in an effort to reduce over-referral to one specialist. Future studies should address the utility of an interprofessional team approach in the overall management of patients with dizziness.