Presence of ipsilateral acoustic reflex artifact may result in clinical misidentification.

OBJECTIVE: Upon calibration of a specific commercially available immittance device, an artifact was consistently measured in a calibration cavity when in ipsilateral acoustic reflex mode. These results were replicated in a controlled fashion, raising concerns about how clinical results might potentially be misinterpreted. DESIGN: Responses were measured from an Interacoustics Titan and Grason-Stadler Tympstar Pro immittance device coupled to a 0.2 cc and, separately, to a 1.0 cc calibration cavity when in ipsilateral acoustic reflex mode. The procedure was repeated with the same outcomes. RESULTS: Clinically significant responses ordinarily associated with presence of an ipsilateral acoustic reflex were obtained in a 0.2 cc and 1 cc coupler with stimuli presented at 0.5 kHz, 1 kHz, and 2 kHz with one of the Interacoustics Titan, but were not obtained in the same conditions with the Grason-Stadler Tympstar Pro. CONCLUSIONS: A commercially available immittance device yielded clinically-significant responses to ipsilateral acoustic reflex stimuli within calibration cavities of various sizes. Results suggest that false-positive responses may be obtained when certain immittance devices are used clinically, producing possible misleading or incorrect clinical impressions and assessment.

Auditory adaptation testing as a tool for investigating tinnitus origin: two patients with vestibular schwannoma.

OBJECTIVE: To enhance the understanding of tinnitus origin by disseminating two case studies of vestibular schwannoma (VS) involving behavioural auditory adaptation testing (AAT). DESIGN: Retrospective case study. STUDY SAMPLE: Two adults who presented with unilateral, non-pulsatile subjective tinnitus and bilateral normal-hearing sensitivity. At the initial evaluation, the otolaryngologic and audiologic findings were unremarkable, bilaterally. Upon retest, years later, VS was identified. RESULTS: At retest, the tinnitus disappeared in one patient and was slightly attenuated in the other patient. In the former, the results of AAT were positive for left retrocochlear pathology; in the latter, the results were negative for the left ear although a moderate degree of auditory adaptation was present despite bilateral normal-hearing sensitivity. Imaging revealed a small VS in both patients, confirmed surgically. CONCLUSION: Behavioural AAT in patients with tinnitus furnishes a useful tool for exploring tinnitus origin. Decrease or disappearance of tinnitus in patients with auditory adaptation suggests that the tinnitus generator is the cochlea or the cochlear nerve adjacent to the cochlea. Patients with unilateral tinnitus and bilateral, symmetric, normal-hearing thresholds, absent other audiovestibular symptoms, should be routinely monitored through otolaryngologic and audiologic re-evaluations. Tinnitus decrease or disappearance may constitute a red flag for retrocochlear pathology.

Temporal integration of the contralateral acoustic reflex threshold for a 1000 hz tonal activator and its age-related changes.

BACKGROUND: Previous research has noted an age effect on the temporal integration of the acoustic reflex for a noise activator. PURPOSE: To determine whether the age effect earlier noted for a noise activator will be noted for a tonal activator. RESEARCH DESIGN: Comparison of ARTs of younger and older groups at activating stimulus durations of 12, 25, 50, 100, 200, 300, 500, and 1000 msec. STUDY SAMPLE: Two groups of adults with normal-hearing sensitivity: one group of 20 young adults (ten males and ten females, ages 18-29 years, with a mean age of 24 years) and one group of 20 older adults (ten males and ten females, ages 59-75 years, with a mean age of 67.5 years). RESULTS: A significant main effect for duration was obtained. That is, as the duration increased, the acoustic reflex threshold for the 1000 Hz tonal activator decreased. The interactions of duration x age group and duration x hearing level were not significant. There was a nonsignificant main effect (p = .889) for the between-subjects factor of age. CONCLUSION: Results contradict the findings for broadband noise.

Technical report: distortion product otoacoustic emissions that are not outer hair cell emissions.

PURPOSE: To present a case study in order to alert clinicians to the possibility of occurrence of intermodulation distortion during otoacoustic emissions testing that arises from the cavity formed by the external auditory meatus and tympanic membrane rather than from the inner ear, compromising the reliability and validity of otoacoustic emissions testing. RESEARCH DESIGN: Prospective case study. STUDY SAMPLE: A young (26-year-old) female adult with a longstanding, bilateral, essentially moderate to severe sensorineural hearing loss presented with robust distortion product otoacoustic emissions. RESULTS: Repeat otoacoustic emissions testing with another device of the same model revealed essentially absent distortion product otoacoustic emissions and transient otoacoustic emissions. Calibration of both otoacoustic emissions devices using a 1 cc membranous cavity indicated present intermodulation distortion for the device that yielded robust distortion product otoacoustic emissions for the patient but absent intermodulation distortion for the device that revealed absent distortion product otoacoustic emissions and absent transient evoked otoacoustic emissions for the patient. The calibration findings for the device yielding intermodulation distortion in the cavity were confirmed by an engineer of a technical instrumentation company. The device was shipped back to the manufacturer of the device for repair. The manufacturer's engineers diagnosed the problem as an interruption in the relay system. Following repair, calibration revealed the absence of intermodulation distortion in the 1 cc membranous cavity. CONCLUSIONS: The findings have implications for the reliability and validity of otoacoustic emissions. Clinicians should routinely calibrate otoacoustic emissions devices using 1.0 and 0.5 cc membranous cavities to rule out intermodulation distortion that could produce artifactual otoacoustic emissions in patients.

Auditory deprivation in adults with asymmetric, sensorineural hearing impairment.

The purpose of this investigation was to prospectively examine performance on the pure-tone air-conduction threshold, speech-recognition threshold, and suprathreshold word-recognition tests over time in 21 monaurally aided (experimental group) and 28 unaided adults (control group) with asymmetric, sensorineural hearing impairment. The results revealed significant declines on the mean suprathreshold word-recognition scores over time at one and two years post-baseline for the worse ears of the control participants; no declines occurred in the worse ears of the experimental participants or in the better ears of either group. A slight, significant increase in the pure-tone average occurred for the better ears of both groups. The findings are consistent with the presence of an auditory deprivation effect on suprathreshold word-recognition ability in the control group, suggesting that lack of amplification leads to decline in word-recognition performance over time in the worse ears of adults with asymmetric sensorineural hearing impairment.

Temporal integration of the contralateral acoustic-reflex threshold and its age-related changes.

Although numerous studies have investigated temporal integration of the acoustic-reflex threshold (ART), research is lacking on the effect of age on temporal integration of the ART. Therefore the effect of age on temporal integration of the ART was investigated for a broad-band noise (BBN) activator. Subjects consisted of two groups of adults with normal-hearing sensitivity: one group of 20 young adults (ten males and ten females, ages 18-29 years, with a mean age of 24 years) and one group of 20 older adults (ten males and ten females, ages 59-75 years, with a mean age of 67.5 years). Activating stimulus durations were 12, 25, 50, 100, 200, 300, 500, and 1000 ms. Significant main effects for duration and age were obtained. That is, as the duration increased, the acoustic reflex threshold for BBN decreased. The interactions of duration x age group and duration x hearing level were not significant. The result of pair-wise analysis indicated statistically significant differences between the two age groups at durations of 20 ms and longer. The observed age effect on temporal integration of the ART for the BBN activator is interpreted in relation to senescent changes in the auditory system.

Nonsurgical home treatment of middle ear effusion and associated hearing loss in children. Part II: Validation study.

In this prospective follow-up investigation, we examined the efficacy of a modified Politzer device in the home treatment of persistent middle ear effusion (MEE) and associated hearing loss in children who had previously participated in a similar clinical trial. Our study group was made up of 38 patients who had been either (1) untreated control participants in the previous study whose hearing in one or both ears had not returned to normal within 11 weeks of their initial audiologic pretest ("former control group"; n = 30), or (2) active-treatment participants in the previous study whose hearing sensitivity in at least one ear had not improved to within normal limits after treatment and who elected to undergo a continuation of treatment ("extended-treatment group"; n = 8). Treatment efficacy was determined by comparing differences in pre- and posttreatment air-conduction thresholds and otoscopic findings. Following treatment, the former control group experienced significant improvements in hearing sensitivity at all frequencies; at the posttreatment test, hearing sensitivity was within normal limits in 43 of 60 ears (71.7%), and normal or moderate tympanic membrane mobility was observed in 30 of 34 otoscopically examined ears (88.2%). In the extended-treatment group, hearing sensitivity returned to within normal limits in 9 of 10 impaired ears (90.0%). These findings further substantiate the efficacy of our modified Politzer device in improving middle ear function and hearing sensitivity in children with MEE, and they support the reliability of the findings reported in our previous study. These results also indicate that many patients in whom initial treatment is not successful may benefit from extended treatment.

The prediction of hearing loss in persons with cerebral palsy using contralateral acoustic reflex threshold for broad-band noise.

The utility of R. Keith's (1977) method of screening for hearing sensitivity using the contralateral acoustic-reflex threshold (ART) for broad-band noise (BBN) was tested in persons with cerebral palsy (CP). Three groups of participants were included in this prospective study. The first group comprised 20 normal-hearing individuals without CP whose results were used as normative data. The second group comprised 16 participants with normal hearing and CP. The third group comprised 22 participants with sensorineural hearing loss and CP. The results of this study indicate that Keith's screening method employing ART for BBN can be used successfully in a population with multiple handicaps where a quick, inexpensive, readily available, and accurate method is needed.