Tinnitus is a common auditory disorder in which patients experience noise in the absence of an external source. It is a consequence of irreversible cochlear damage. This study examined the distortion product otoacoustic emissions and P300 components of event-related potentials.

This study included a control group of 25 normal-hearing adults not complaining of tinnitus and a study group that consisted of 45 normal-hearing adults complaining of tinnitus. Measures included patient history, basic audiological evaluation, the Arabic version of Tinnitus Handicap Inventory, distortion product otoacoustic emissions testing and P300 recording.

The study group showed significantly higher hearing thresholds at all frequencies as well as delayed latencies and reduced amplitude of P300. The Tinnitus Handicap Inventory showed mean scores of 35.2 ± 16.9, and the distortion product gram showed higher amplitudes in the control group.

Patients with tinnitus might have neural dysfunction at either peripheral or central levels of the auditory pathway.

This study aimed to research risk factors of hearing loss among neonates in the neonatal intensive care unit.

Hearing screening tests were performed on 572 neonates in the neonatal intensive care unit. Those who failed screening tests were referred for diagnostic tests.

The pass rates for automated auditory brainstem response, distortion product otoacoustic emission and acoustic impedance tests at first hearing screening were 69.93 per cent, 70.02 per cent and 92.92 per cent for 1144 ears. Failure in the first screening correlated with preterm birth, very low birth weight, revised advanced maternal age, neonatal hyperbilirubinaemia and Activity, Pulse, Grimace, Appearance, Respiration score less than 8. Thirty cases failed in diagnostic hearing tests for brainstem auditory evoked potentials, 28 failed in otoacoustic emissions and 33 failed in acoustic impedance, which correlated with preterm birth, very low birth weight, twins, advanced maternal age and revised advanced maternal age.

Abnormalities in the hearing levels of most neonates who needed hearing retests were completely or partially reversible. Preterm birth, very low birth weight, twins and advanced maternal age are potential risk factors for hearing impairment.

Otological complications are considered early symptoms of severe acute respiratory syndrome coronavirus-2; however, it is unknown how long these symptoms last and whether the virus leaves any hearing disorders post-recovery.

This prospective cohort study comprised 31 mild or moderate confirmed coronavirus disease 2019 patients and 26 age-matched control peers (21–50 years old). Patients were questioned about their otological symptoms, and their hearing status was assessed during one month post-diagnosis.

Patients showed a significantly higher rate of otological symptoms (hearing loss, ear fullness, ear pain, dizziness or vertigo, communication difficulties, and hyperacusis) versus the control group (p ≤ 0.022). The symptoms resolved early, between 2 and 8 days after their appearance. No significant differences were observed between the two groups in pure tone and extended high-frequency audiometry, transient evoked otoacoustic emissions, distortion product otoacoustic emissions, or auditory brainstem response following recovery.

The findings indicate that, in mild to moderate coronavirus disease 2019 cases, otological symptoms resolve within a week, and the virus has no lasting impact on the auditory system.

To measure the output sound pressure levels of personal music systems and evaluate their effect on hearing.

Output sound pressure levels at preferred volume settings and listening environment were measured using a manikin. Effects of personal music system use on hearing were evaluated using pure tone audiometry (in conventional and extended high frequency ranges), transient evoked otoacoustic emissions, syllable identification in noise, intensity discrimination, frequency discrimination and temporal modulation transfer function.

Results showed, alarmingly, that large proportions of young adults are using personal music systems at levels higher than the safety limits set by regulatory bodies. Individuals who listened to personal music systems at levels higher than 80 dB LAeq exhibited poorer extended high frequency thresholds, reduced transient evoked otoacoustic emission amplitudes, poorer frequency discrimination, reduced modulation detection thresholds at 32 Hz modulation frequency, and reduced syllable identification in noise at −5 dB signal-to-noise ratio. Listening levels were significantly correlated with extended high frequency thresholds and transient evoked otoacoustic emission amplitudes.

These results suggest that listening to music through personal music systems at higher volume levels may be hazardous to hearing.

To explain a clinical observation: a notch in the stimulus spectrum during transient evoked otoacoustic emission measurement in ears with secretory otitis media.

The effects of tympanic under-pressure were investigated using a pressure chamber. A model of the ear canal was also studied.

Tympanic membrane reflectance increased as a consequence of increased stiffness, causing a notch in the stimulus spectrum. In an adult, the notch could be clearly distinguished at an under-pressure of approximately −185 daPa. The sound frequency of the notch corresponded to a wavelength four times the ear canal length. The ear canal of infants was too short to cause a notch within the displayed frequency range. The notch was demonstrated using both Otodynamics and Madsen equipment.

A notch in the otoacoustic emission stimulus spectrum can be caused by increased stiffness of the tympanic membrane, raising suspicion of low middle-ear pressure or secretory otitis media. This finding is not applicable to infants.

Description of a female patient with diagnosed Kjer's disease and sensorineural hearing loss, who specifically complained of a progressive inability to understand speech in noisy situations.

Case report.

A 30-year-old, Caucasian woman with Kjer's disease.

Audiological assessment showed low-frequency sensorineural hearing loss and a disproportionate deterioration in speech discrimination. This inconsistency gave rise to suspicion of possible aggravation. Follow-up testing showed that brainstem responses were absent, while clear otoacoustic emissions and cochlear microphonics were present. Hearing aids were fitted but no improvement was shown.

This case shows a combination of auditory neuropathy and Kjer's optic neuropathy. It also illustrates that the combination of unexplained hearing loss and apparently inconsistent audiometric outcomes may be associated with auditory neuropathy. Such unexpected hearing evaluation outcomes may be due to other neurological conditions, such as Kjer's disease.

To investigate the correlation between cochlear processing and brainstem processing.

Transient evoked otoacoustic emissions and speech-evoked auditory brainstem responses were recorded in 40 ears of normal-hearing individuals aged 18 to 23 years. Correlation analyses compared transient evoked otoacoustic emission parameters with speech-evoked auditory brainstem response parameters.

There was a significant correlation between speech-evoked auditory brainstem response wave V latency and transient evoked otoacoustic emission global emission strength; there were no other significant correlations between the two tests.

Tests for transient evoked otoacoustic emissions and speech-evoked auditory brainstem responses provide unique and functionally independent information about the integrity and sensitivity of the auditory system. Therefore, combining both tests will provide a more sensitive clinical battery with which to identify the location of different disorders (e.g. language-based learning impairments and hearing impairments).

Allergic rhinitis is associated with excess specific immunoglobulin E. Inner ear involvement (via both cellular and humoral immunity) is poorly understood, but appears to arise from the endolymphatic sac and duct.

To assess the otological and audiological status of patients with allergic rhinitis.

Thirty allergic rhinitis patients (14 men, 16 women; age 17–45 years, mean 31 years) and 20 controls (12 men, eight women; age 21–42 years, mean 27 years) underwent audiological investigation.

All study group patients had sensorineural (rather than conductive) hearing loss, worse at high frequencies. All had abnormal transient evoked otoacoustic emissions and 27 had abnormal distortion product otoacoustic emissions. All had a statistically significantly prolonged wave I latency, and shortened absolute wave I–III and I–V interpeak latencies, compared with controls.

Allergic rhinitis patients had a higher prevalence of hearing loss and otoacoustic emission abnormalities than controls. The endolymphatic sac can process antigens and produce its own local antibody response; the resulting inflammatory mediators and toxic products may interfere with hair cell function. Additional research is needed to determine the clinical value of audiometry and otoacoustic emission testing in allergic rhinitis.

This study aimed to evaluate the sensitivity of transient evoked otoacoustic emission testing as a screening tool for hearing loss in children, after grommet insertion.

A prospective study was conducted of 48 children (91 ears) aged three to 16 years who had undergone grommet insertion for glue ear. At post-operative review, pure tone audiometry was performed followed by transient evoked otoacoustic emission testing. Outcomes for both tests, in each ear, were compared.

The pure tone audiometry threshold was ≤20 dB in 85 ears (93.4 per cent), 25 dB in two ears (2.2 per cent) and ≥30 dB in four ears (4.4 per cent). Transient evoked otoacoustic emissions were detected in 69 ears (75.8 per cent). The sensitivity of transient evoked otoacoustic emission testing for detecting hearing loss was 100 per cent for ≥30 dB loss but only 66.7 per cent for ≥25 dB loss.

Transient evoked otoacoustic emission testing offers a sensitive means of detecting hearing loss of ≥30 dB following grommet insertion in children. However, the use of such testing as a screening tool may miss some cases of mild hearing loss.

High sodium salicylate doses can cause reversible hearing loss and tinnitus, possibly due to reduced outer hair cell electromotility. Sodium salicylate is known to alter outer hair cell structure and function. This study determined the reversibility and cochlear recovery time after administration of an ototoxic sodium salicylate dose to guinea pigs with normal cochlear function.

Prospective experimental investigation.

All animals received a single 500 mg sodium salicylate dose, but with different durations of action. Function was evaluated before drug administration and immediately before sacrifice. Cochleae were processed and viewed using scanning electron microscopy.

Changes in outer hair cell function were observed to be present 2 hours after drug administration, with recovery of normal anatomy beginning after 24 hours. Subsequently, derangement and distortion of cilia reduced, with effects predominantly in row three. At 168 hours, cilia were near-normal but with mild distortions which interfered with normal cochlear physiology.

Ciliary changes persisted for up to 168 hours after ototoxic sodium salicylate administration.

To study the effects of the electromagnetic field emitted by cellular telephones upon the inner ear of rats, using distortion product otoacoustic emissions.

Forty Wistar Albino rats were used. Twenty newborn and 20 adult rats were divided into two groups of 10, one to participate in the study and one as a control. The rats were exposed to the electromagnetic field for 6 hours per day, for 30 consecutive days. Before and after the 30 day exposure period, distortion product otoacoustic emissions were measured in each group and a signal-to-noise ratio calculated, which was later used in statistical analysis.

For both the newborn and adult rat groups, there was no significant difference in distortion product otoacoustic emissions recorded before and after exposure to the cellular telephone electromagnetic field (p > 0.05).

Exposure to the electromagnetic field emitted by cellular telephones, for 6 hours a day for 30 consecutive days, had no effect on the hearing of newborn or adult rats, at the outer ear, middle ear or cochlear level.

Auditory neuropathy is a disorder characterised by preservation of outer hair cell function, with normal otoacoustic emissions and/or cochlear microphonics, but an absent or distorted auditory brainstem response.

This study aimed to objectively assess hearing thresholds in patients with auditory neuropathy, using the auditory steady state response.

Thirteen patients with auditory neuropathy and 15 normal hearing subjects were examined. Audiological evaluation included basic audiological tests, otoacoustic emissions, auditory brainstem response and auditory steady state response.

In the auditory neuropathy patients, the auditory brainstem response was absent in 11 patients, while the auditory steady state response was absent in only three.

The auditory steady state response may serve as a valuable objective measure for assessing the hearing threshold across different frequencies in patients with auditory neuropathy. We recommend that auditory steady state response be used to complete the evaluation of patients with auditory neuropathy.

Prospective, case–control study.

The study included 26 randomised patients with systemic lupus erythematosus (52 ears) and 30 healthy control subjects (60 ears). Pure tone audiometry was performed at 250 and 500 Hz and at 1, 2, 4, 6, 8, 10, 12, 14 and 16 kHz. Distortion product otoacoustic emissions and transient evoked otoacoustic emissions were measured using Biologic System equipment with Scout Acoustic Emissions System software.

The distortion product otoacoustic emission signal responses were significantly different only at 750 Hz, while the distortion product otoacoustic emission signal–noise ratios were significantly different at 750 Hz and 6 kHz (p < 0.05), comparing patients and controls. The transient evoked otoacoustic emission signal–noise ratios were significantly different at 2 and 3 kHz, comparing patients and controls (p < 0.05). The transient evoked otoacoustic emission total signal–noise ratios were significantly different, comparing patients and controls (p < 0.05). In addition, the pure tone audiometry thresholds were significantly different at 250 and 500 Hz and at 1, 2, 10 and 12 kHz, comparing patients and controls (p < 0.05).

Our findings do not completely agree with those of previous temporal bone histopathological studies. However, our results do support a general picture of low frequency hearing loss in systemic lupus erythematosus patients. We consider these results to be related to endolymphatic and cochlear hydrops, and we suggest that electrocochleography could be performed in further studies for clarification of this subject.

To evaluate distortion product otoacoustic emissions following stapes surgery in patients with otosclerosis, and to compare in this respect two surgical techniques used in our department.

This retrospective study included 17 stapedectomy and 23 stapedotomy patients aged 16–68 years who had been followed up for at least 12 months. Distortion product otoacoustic emission results at 2, 3, 4 and 5 kHz (i.e. =f2, with 2f1 − f2 = 0.6f2) were obtained pre-operatively and four weeks post-operatively. The control group included 13 volunteers aged 18–50 years with normal hearing and normal otoscopic findings.

Distortion product otoacoustic emissions were detected pre-operatively in 34.8 per cent of stapedotomy patients and 29.4 per cent of stapedectomy patients, and post-operatively in 91.3 per cent of stapedotomy patients and 88.2 per cent of stapedectomy patients. The differences between the stapedotomy and stapedectomy groups were statistically insignificant for each tested frequency, both pre- and post-operatively. The patients' post-operative distortion product otoacoustic emission amplitudes were less than those of normal hearing individuals, even in patients with complete air–bone gap closure and a significant improvement in hearing.

Distortion product otoacoustic emissions were detected in most of our patients following successful stapes surgery, and appeared to be unaffected by the surgical technique or prosthesis used.

Hearing sensitivity usually diminishes with noise exposure. In the present study, we examined the effect of 93 dB(A) wide band noise on cochlear micromechanical sensitivity in awake guinea pigs.

Animals were randomly assigned to groups receiving either single or repeated noise exposure. Distortion product otoacoustic emission amplitudes were recorded before, during and after noise exposure.

Ninety-three decibel(A) wide band noise reduced the distortion product otoacoustic emission amplitudes at all tested frequencies. The distortion product otoacoustic emission amplitudes for higher frequencies showed a permanent reduction, whereas those for lower frequencies showed a temporary reduction. Distortion product otoacoustic emission amplitudes for middle frequencies showed prolonged enhancement after repeated noise exposure.

Our results suggest that (1) it is likely that there are intermediate stages between permanent threshold shift and temporary threshold shift, and (2) long-term enhancement of distortion product otoacoustic emission amplitudes may be an indication of tinnitus generation.

To study the effects of hypobaric pressure chamber exposure on the cochlear frequency selectivity of subjects with monaural, fluctuating, low-frequency hearing loss, such as occurs in Ménière's disease.

We used a hypobaric pressure chamber to create relative underpressure in the ear canal, in order to impose positive pressure gradients on the inner ear. Psychophysical tuning curves, transiently evoked otoacoustic emissions and speech recognition scores in noise were measured in 10 subjects with fluctuating, low-frequency hearing loss, before and after pressure exposure.

After the exposure, subjects’ overall pure tone averages showed no improvement, but individual results showed improved speech recognition scores in noise (six subjects), increased transiently evoked otoacoustic emission strength (three subjects) and increased psychophysical tuning curve steepness (two subjects). Deteriorations were also seen, mainly in psychophysical tuning curves. No association could be established between the different tests, and the measured parameters could not predict subjective improvement.

The results suggest variable effects of hypobaric pressure exposure on inner-ear physiology.

The characteristics of otoacoustic emissions that make them ideally suited for universal newborn hearing loss screening could potentially be useful for the screening of older children. This study was performed in order to assess the role of otoacoustic emissions in a screening programme for middle-ear disorders and hearing loss in school-age children.

Cross-sectional, preliminary screening study.

Primary schools of Argolida municipality, south-east Greece, between December 2004 and March 2005.

All the primary school students of Argolida were invited, by press releases and individually by their teachers, to attend a session of otological and audiological screening.

One hundred and ninety-six children were evaluated using transient evoked otoacoustic emissions. Twenty per cent failed in both ears, while in 32 per cent otoacoustic emissions could not be produced in at least one ear. Younger children had higher rates of absent transient evoked otoacoustic emissions. The absence of otoacoustic emissions was highly correlated with tympanic membrane changes seen on otoscopy and the presence of a type B tympanogram. As a single screening modality, otoacoustic emissions had a 100 per cent sensitivity in diagnosing hearing loss worse than 30 dB, and a 90 per cent sensitivity and 64 per cent specificity in diagnosing hearing loss worse than 25 dB, which did not improve by adding tympanometry to the screening protocol.

These results strongly suggest the potential usefulness of otoacoustic emission testing in screening school-age children for hearing loss. Further studies, taking into account cost-effectiveness issues, are indicated.

To assess contralateral suppression of transiently evoked otoacoustic emissions in patients with fibromyalgia syndrome and normal hearing.

Twenty-four female patients with fibromyalgia syndrome and 24 healthy female controls with normal hearing were assessed using pure tone audiometry and transiently evoked otoacoustic emissions.

All patients with fibromyalgia syndrome and all controls had normal hearing on pure tone audiometry. In the patients with fibromyalgia syndrome, the mean transiently evoked otoacoustic emission amplitude was 15.5 ± 4.8 dB. The mean transiently evoked otoacoustic emission amplitudes after contralateral suppression was 15.5 ± 4.9 dB. There was no statistically significant difference between the transiently evoked otoacoustic emission amplitudes measured before and after contralateral suppression (p > 0.05). In the controls, the mean transiently evoked otoacoustic emission amplitude was 12 ± 5 dB. The mean transiently evoked otoacoustic emission amplitudes after contralateral suppression was 11 ± 4.7 dB. There was a statistically significant decrease in transiently evoked otoacoustic emission amplitudes after contralateral suppression (p < 0.01).

The mechanisms related to contralateral suppression of transiently evoked otoacoustic emissions seem dysfunctional in fibromyalgia syndrome. This dysfunction may be at the brain stem level, where the medial superior olivary complex is located, or at the synapses of medial superior olivary complex fibres with the outer hair cells in the cochlea. Demonstration of lack of contralateral suppression of transiently evoked otoacoustic emissions can be used as a diagnostic tool in patients with fibromyalgia syndrome.

We report a rare case of otological presentation of craniopharyngioma.

Case report and review of world literature concerning presentations of craniopharyngioma.

A six-year-old girl was referred to our department with unilateral hearing loss. This appeared to be a complete sensorineural hearing loss. Otoacoustic emissions were reproducible on both sides. Magnetic resonance scanning revealed a massive, cystic craniopharyngioma exerting pressure on the patient's ventricular system and brainstem and also invading the internal acoustic canal. The mass was resected via a craniotomy. The patient's hearing loss completely recovered, and she experienced no neurological or endocrinological side effects of the treatment. Craniopharyngioma have a prevalence of 0.13–2:100 000.

Craniopharyngioma is a rare disease. First presentation with otological symptoms is extremely rare. Otoacoustic emissions can differentiate between cochlear and retrocochlear causes of sensorineural hearing loss.