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.

Objective computerized versus subjective analysis of facial synkinesis.

OBJECTIVES/HYPOTHESIS: To compare the sensitivity of an objective, computerized approach to measurement of facial synkinesis with that for a subjective approach and to examine the test-retest reliability of these approaches. STUDY DESIGN: Prospective, nonrandomized, and blinded. METHODS: Remote facial motion at the upper eyelids and oral commissures during a closed-lip smile and eyelid closure were measured using a commercially available computerized motion analysis system. Thirty healthy adults with normal facial nerve function were enrolled to establish normative data and a threshold value for synkinesis. Thirty consecutive patients were analyzed based on the synkinesis threshold value. Blinded subjective evaluations by two observers were also performed independently on the same patients. RESULTS: Facial synkinesis was detected significantly more frequently with objective than subjective analysis for eyelid closure; no significant differences between approaches were shown for the closed-lip smile. Interestingly, five (17%) patients developed early synkinesis within 3 months from the onset of the facial nerve injury. The test-retest reliability of all objective measures was excellent for both expressions. Close agreement in percent of patients with synkinesis between test and retest subjective evaluations was obtained for both observers for both expressions. CONCLUSIONS: The objective, computerized approach to detection of facial synkinesis has excellent reliability and is more sensitive than the subjective approach to assessment to the presence of facial synkinesis associated with eyelid closure. The finding of early synkinesis suggests that central nervous reorganization plays a role in regeneration of the facial nerve.

Parental restriction of children's access to cochlear implants: case studies.

This article reports on four retrospective case studies in which parental behavioral management of the implanted child included withholding the cochlear implant or activities associated with it as a disciplinary measure or as a means of preventing device loss or damage. The need for parental counseling by health care and educational professionals as to the importance of a child's connection to the hearing world all day long through the implant for optimal speech, language, academic, and psychosocial development is emphasized.

Facial motion analysis with a video and computer system after treatment of acoustic neuroma.

OBJECTIVE: To objectively evaluate facial function with a computer and video system in a group of normal adults and a group of adults who have been treated for acoustic neuroma. STUDY DESIGN: A prospective descriptive study was performed in which the experimenter performing the objective facial motion analysis was blinded to the subjective rating of facial function. PATIENTS: The normal subjects comprised 18 women and 16 men. The subjects who had been treated for acoustic neuroma included 12 patients (seven women and five men) who underwent treatment for acoustic neuroma. METHODS: Light-reflective markers were placed at selected facial sites. A video and computer-assisted system was used to measure displacement that was unconfounded by head motion at these sites during two expressions. Proximal and remote displacement were measured for the x and y coordinates. Percentage of asymmetry relative to the total displacement was determined. RESULTS: Significant asymmetry in displacement for the y coordinate during the eyes-closed expression occurred in 100% of the subjects who had been treated for acoustic neuroma with apparent facial dysfunction and 0% of the subjects who had been treated for acoustic neuroma with no apparent facial dysfunction. Synkinesis was severe (>0.2 cm) in 17%, moderate (0.1-0.2 cm) in 25%, mild (>95th percentile for normal subjects but <0.1 cm) in 42%, and absent in 16% of the subjects who had been treated for acoustic neuroma. CONCLUSION: This method of objective assessment of facial function is useful in the evaluation of the asymmetry in facial motion and in the detection and quantification of synkinesis. The findings suggest that those subjective rating systems of facial function that compare the abnormal to the normal side may be confounded by compensatory motion on the presumed normal side.

How to measure cerebrospinal fluid pressure invasively and noninvasively.

We describe tympanic membrane displacement (TMD) testing for non-invasive estimation of intracranial pressure (ICP). With the TMD test, displacement of the tympanic membrane of the middle ear is recorded during elicitation of the acoustic middle-ear reflex (AR). Increased intracranial/perilymphatic pressure displaces the resting stapes footplate laterally so that TMD during the acoustic reflex is medial. Decreased intracranial/perilymphatic pressure displaces the baseline stapes footplate position medially (inward) so that TMD during the AR is lateral. The TMD typically is bidirectional when intracranial/perilymphatic pressure is normal. Discrepant findings have been reported for the sensitivity of the TMD test to ICP as the regression of TMD on invasive measurement of the ICP reveals substantial intersubject variability and overlap among patient and control groups. Large-sample research on TMD test performance in healthy persons and patients with various disorders affecting the ICP is needed using direct, invasive measures of the ICP as the gold standard. Research also is needed to examine whether non-invasive TMD testing can be used to investigate the trans-lamina cribrosa pressure difference in glaucoma.

Repair issues associated with cochlear implants in children.

OBJECTIVE: To examine the number and type of repair issues associated with the use of cochlear implants in children who have worn either the body-level or ear-level style for 4 to 5 years. STUDY DESIGN: Retrospective review. SETTING: Specialty eye and ear institute. METHODS: Charts for all children who received cochlear implants from one of the authors between 1994 and 2002 and who received 4 to 5 years of follow-up for either the body or the ear-level style were examined. Based on the return merchandise authorizations and chart notes, implant problems were classified as external or internal. External problems were further subclassified as affecting the batteries, case, earhook, cords/cables, microphone, speech processor, coil, and/or external magnet; internal problems were subclassified as affecting the internal magnet, electrode(s), or other. MAIN OUTCOME MEASURES: Type and number of internal and external cochlear implant component breakdowns over time (including external component repair rates per year) and number of associated hospital visits. RESULTS: Of the 22 children, 4 (18.2%) had internal component problems. For the external components, the repair rate per year was 4.1 and 2.7 for the body style and ear-level style, respectively. For the group of children who was seen for each of 4 years, the mean number of repair problems declined 32% and 43% over that period for the body-worn and ear-level implants, respectively. The mean repair cost per year, based on Years 4 and 5 of use, was $794 and $317 for the body-worn and ear-level styles, respectively. CONCLUSION: The declines over time in repair problems and associated hospital visits suggest that children learn, over time, to better maintain and care for their cochlear implant. Although most had external component breakdowns, relatively few had internal component repair issues.

Efficacy of the bone-anchored hearing aid for single-sided deafness.

OBJECTIVES/HYPOTHESIS: The aim was to examine short- and long-term efficacy of the bone-anchored hearing aid (BAHA) on adults with single-sided deafness. STUDY DESIGN: Prospective investigation. METHODS: The outcome measures included the Hearing in Noise Test (HINT), Abbreviated Profile of Hearing Aid Benefit (APHAB), and Single-Sided Deafness Questionnaire (SSD). The BAHA group comprised seven adults with single-sided deafness and the control group comprised 20 adults with essentially normal-hearing sensitivity, bilaterally. The outcome measures were administered in the unaided, directional BAHA, and omnidirectional BAHA conditions after 1 month, 6 months, and 12 months of BAHA use. A repeated measures analysis of variance (ANOVA) model was used to evaluate the data (for the SSD, a nonparametric analog of ANOVA was employed). RESULTS: None of the factors (time, HINT condition, amplification status) or their interactions were significant predictors of change in signal-to-noise ratio (SNR) from baseline over time on the HINT. The mean SNR (non-baseline-subtracted) was significantly lower in the directional BAHA versus the unaided status and in the omnidirectional BAHA versus the unaided status, but only under the noise in front, speech lateralized to the bad ear HINT condition. Significant short- and long-term BAHA benefit was observed on the APHAB (all subscales except Aversiveness) and SSD (all questionnaire items). CONCLUSIONS: Our results show short- and long-term efficacy for the BAHA in adults with single-sided deafness for recognition of speech in noise (noise in front, speech lateralized to the bad ear) and on subjective measures of benefit.

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.