Effects of Occlusion and Conductive Hearing Loss on Bone-Conducted cVEMP.

OBJECTIVE: To evaluate the effects of conductive hearing loss and occlusion on bone-conducted cervical vestibular evoked myogenic potentials (cVEMPs). STUDY DESIGN: Prospective cohort study conducted in the year 2018. The right ear of each volunteer was evaluated under 3 conditions by using bone-conducted cVEMPs: normal (open external auditory canal), occluded (conductive hearing loss with occlusion effect), and closed (conductive hearing loss without the occlusion effect). SETTING: Single academic center. SUBJECTS AND METHODS: The study comprised 30 healthy volunteers aged 20 to 35 years (16 women, 14 men). All had normal hearing and no vestibular or auditory pathologies. The thresholds and amplitudes of cVEMP responses were recorded for the 3 conditions. The results of each condition for a particular participant were compared. RESULTS: As compared with the open condition, the conductive condition increased thresholds by 2.8 dB (P = .01), and the occluded condition decreased thresholds by 3.8 dB (P = .008). The amplitude in the occluded condition was larger than the normal condition and the conductive condition (mean difference: 20.64 [P = .009] and 31.76 [P < .001], respectively). CONCLUSION: The occlusion effect is present in cVEMP responses. The mechanism is not due to the conductive hearing loss induced. Clinical implications include potentially altering vestibular function with sealed hearing aids and in the surgically modified ears (ie, obliterated ears and open cavity mastoidectomy).

The impact of conductive hearing loss on balance.

BACKGROUND: Balance is a complex process involving the coordinated activities of multiple sensory, motor and biomechanical components. Balance function may be disturbed in subjects suffering from hearing loss but the impairment has been attributed to the pathology underlying the hearing loss. AIM: The purpose of the study was to investigate the possible interference of simulated conductive hearing loss with the ability to maintain postural balance. METHODS: Twenty normal-hearing subjects, 20-30 years old, underwent the computerised dynamic posturography test battery before and after plugging their external ear canals with earplugs, thus simulating a 40dB conductive hearing loss. RESULTS: Eighteen females and two males were tested before and after plugging their ear canals. Average CHL was 40 ± 4.9dB. The composite equilibrium score was significantly diminished after plugging the ears with an average sway score of 73.5% (P < .05, T = 2.27). The fourth test condition was specifically affected with an average sway score of 72.85% with earplugs (P < .05, T = 2.37). CONCLUSIONS: Conductive hearing loss has a negative effect on balance. This can be theoretically explained by the association between hearing loss and saccular dysfunction.

The occlusion effect in bone conducted cVEMP.

BACKGROUND: Vestibular evoked myogenic potentials (VEMP) are transient alteration in tonic activity of muscles elicited by auditory stimulation of the otolithic organs of the ear. VEMP can be triggered by auditory stimulation via air or bone conduction. Occlusion of the external auditory meatus has long been known to decrease thresholds for sound perception medicated by the cochlea. OBJECTIVE: Proof that the occlusion effect is present for bone conducted (BC) cervical VEMPs (cVEMP). METHODS: Measurement of the thresholds and raw amplitudes of BC-VEMPs in twenty healthy adults with the external auditory canal open and occluded. RESULTS: Thresholds for BC-VEMPs were similar for the open vs. the occluded condition. However, amplitudes were statistically significantly higher in the occluded (average 76.34µV) vs. open group (average 69.9µV). CONCLUSIONS: The occlusion effect is present in cVEMPs. This finding, described herein for the first time, has a number of clinical implications such as the surgically altered ear and the use of occluding hearing aids.

Smartphone-based audiometric test for screening hearing loss in the elderly.

Hearing loss is widespread among the elderly. One of the main obstacles to rehabilitation is identifying individuals with potentially correctable hearing loss. Smartphone-based hearing tests can be administered at home, thus greatly facilitating access to screening. This study evaluates the use of a smartphone application as a screening tool for hearing loss in individuals aged ≥ 65 years. Twenty-six subjects aged 84.4 ± 6.73 years (mean ± SD) were recruited. Pure-tone audiometry was administered by both a smartphone application (uHear for iPhone, v1.0 Unitron, Canada) and a standard portable audiometer by trained personnel. Participants also completed a questionnaire on their hearing. Pure-tone thresholds were compared between the two testing modalities and correlated with the questionnaire results. The cutoff point for failing screening tests was a pure tone average of 40 dB for the frequencies 250-6,000 Hz. The smartphone application's pure tone thresholds were higher (poorer hearing) than the audiometric thresholds, with a significant difference in all frequencies but 2,000 Hz. The application and the audiometric values were in agreement for 24 subjects (92 %). The application had a sensitivity of 100 % and specificity of 60 % for screening compared with the audiometer. The questionnaire was significantly less accurate, having assigned a passing score to three participants who failed both the application and audiometric tests. While a smartphone application may not be able to accurately determine the level of hearing impairment, it is useful as a highly accessible portable audiometer substitute for screening for hearing loss in elderly populations.

Sensitivity of the Automated Auditory Brainstem Response in Neonatal Hearing Screening.

BACKGROUND: In a 2-stage neonatal hearing screening protocol, if an infant fails the first-stage abstract screening with an otoacoustic emissions test, an automated auditory brainstem response (ABR)test is performed. The purpose of this study was to estimate the rate of hearing loss detected byfirst-stage otoacoustic emissions test but missed by second-stage automated ABR testing. METHODS: The data of 17 078 infants who were born at Lis Maternity Hospital between January 2013 and June 2014 were reviewed. Infants who failed screening with a transient evoked otoacoustic emissions (TEOAE) test and infants admitted to the NICU for more than 5 days underwent screening with an automated ABR test at 45 decibel hearing level (dB HL). All infants who failed screening with TEOAE were referred to a follow-up evaluation at the hearing clinic. RESULTS: Twenty-four percent of the infants who failed the TEOAE and passed the automated ABR hearing screening tests were eventually diagnosed with hearing loss by diagnostic ABR testing (22/90). They comprised 52% of all of the infants in the birth cohort who were diagnosed with permanent or persistent hearing loss .25 dB HL in 1 or both ears (22/42).Hearing loss .45 dB HL, which is considered to be in the range of moderate to profound severity, was diagnosed in 36% of the infants in this group (8/22), comprising 42% of the infants with hearing loss of this degree (8/19). CONCLUSIONS: The sensitivity of the diverse response detection methods of automated ABR devices needs to be further empirically evaluated.

Smartphone-based hearing test as an aid in the initial evaluation of unilateral sudden sensorineural hearing loss.

Sudden sensorineural hearing loss (SSNHL) can cause significant morbidity. Treatment with steroids can improve outcome. Delay in initiation of treatment reduces the chance to regain hearing. For this reason SSNHL is considered an emergency. Diagnosis is based on history, physical examination and a standard audiogram, the latter requiring specialized equipment and personnel. Standard audiogram may not be available at the time and place of patient presentation. A smartphone or tablet computer-based hearing test may aid in the decision to prescribe steroids in this setting. In this study the uHear™ hearing test application was utilized. The output of this ear-level air conduction hearing test is reported in hearing grades for 6 frequencies ranging from 250 to 6000 Hz. A total of 32 patients with unilateral SSNHL proven by a standard audiogram were tested. The results of standard and iPod hearing tests were compared. Based on the accepted criterion of SSNHL (at least 30 dB loss - or 2 hearing grades - in 3 consecutive frequencies) the test had a sensitivity of 0.76 and specificity of 0.91. Using a less stringent criterion of a loss of 2 hearing grades over at least 2 frequencies the sensitivity was 0.96 and specificity 0.86. The correlation coefficient for the comparison of the average hearing grade across the 6 measured frequencies of the study and standard audiogram was 0.83. uHear more accurately reflected hearing thresholds at mid and high tones. Similarly to previously published data, low frequency thresholds could be artificially elevated. In conclusion, uHear can be useful in the initial evaluation of patients with single-sided SSNHL by providing important information guiding the decision to initiate treatment before a standard audiogram is available.

Blast injury of the ear in a confined space explosion: auditory and vestibular evaluation.

BACKGROUND: The ear is the most frequent organ affected during an explosion. Recognition of possible damage to its auditory and vestibular components, and particularly the recovery time of the incurred damage, may help in planning the optimal treatment strategies for the otologic manifestations of blast injury and preventing deleterious consequences. OBJECTIVE: To report the results of the oto-vestibular initial evaluation and follow-up of 17 survivors of a suicide terrorist attack on a municipal bus. METHODS: These 17 patients underwent periodic ear inspections and pure tone audiometry for 6 months. Balance studies, consisting of electronystagmography and computerized dynamic posturography were performed at the first time possible. RESULTS: Complaints of earache, aural fullness and tinnitus resolved, whereas dizziness persisted in most of the patients. By the end of the follow-up, 15 (55.6%) of the eardrum perforations had healed spontaneously. Hearing impairment was detected in 33 of the 34 tested ears. Recovery of hearing was complete in 6 ears and partial in another 11. ENG and CDP were performed in 13 patients: 5 had abnormal results on CDP while the ENG was normal in all the patients. Of the seven patients who complained of vertigo, only one improved and was free of symptoms 1 month after the explosion. CONCLUSION: Exposure to a high powered explosion in a confined space may result in severe auditory and vestibular damage. Awareness of these possible ear injuries may prevent many of the deleterious consequences of such injuries.