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Results for “Recruitment Detection, Audiologic”

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150 records · Page 9Linked to original sources
PubMed1998

Vestibular decruitment, hyperactivity, and rebound caloric nystagmus.

OBJECTIVE: This study examined the collective sensitivities of decruitment, hyperactivity, and rebound caloric nystagmus (RCN) for lesions of the brain stem/cerebellum against the current gold standard of imaging, the contrast enhanced magnetic resonance imaging (MRI). STUDY DESIGN: This is a retrospective study of patients who underwent a vestibular evaluation and a contrast-enhanced MRI scan. SETTING: The study was performed at a tertiary referral center. PATIENTS: The patients included in this study were evaluated for investigation of a variety of reported problems, including vertigo/dysequilibrium, headache, hearing loss, and tinnitus. Their age range was 13 to 79 years. INTERVENTION: Every patient underwent a vestibular evaluation, which included the Torok monothermal caloric test and an MRI scan. MAIN OUTCOME MEASURES: The results of this caloric test include vestibular decruitment, hyperactivity, and rebound caloric nystagmus. The sensitivity and specificity of these results for MRI confirmed brain stem/cerebellar lesions were determined. RESULTS: The overall sensitivity of the measures of this caloric test was 90%. The overall specificity was 25%. CONCLUSIONS: As a screening test for brain stem cerebellar lesions, the Torok monothermal caloric test performs well in terms of its sensitivity. The specificity is low, and this probably because MRI looks at morphology rather than function.

Adolescent↗
PubMed1994

[Loudness scaling. A procedure for quantitative recruitment detection].

Direct loudness scaling has been known as an audiological tool for about four decades. Although numerous publications have shown its clinical importance, loudness scaling has not been used in audiology and hearing aid fitting until now. This might be due to the lack of audiometers equipped with loudness scaling devices as well as missing evidence for its clinical applicability. In this study normal data for a single-step direct scaling procedure were established and loudness determinations of 105 patients with sensorineural hearing losses collected. The results show that normal level loudness functions exhibit very similar shapes for narrow band stimulation in the frequency range of 500 to 4000 Hz. However, loudness scaling is affected by the gender of the subjects: females scale systematically louder than do males. In hearing-impaired subjects the slopes of the level loudness functions tend to decrease with increasing hearing loss, indicating negative recruitment. This holds particularly true in the high-frequency range, e.g. at 4000 Hz. Our long-term experience with single-step direct loudness scaling has proven its clinical feasibility in typical patients of an audiology unit. Loudness scaling will prove useful for the localization of hearing impairments, as it can be employed as a quantitative indicator of recruitment without any restrictive preconditions. In addition, it allows the evaluation of hearing aids and cochlear implants by frequency-specific gain measurement.

Audiometry, Pure-Tone↗
PubMed2006

Diagnostics of the cochlear amplifier by means of distortion product otoacoustic emissions.

Distortion product otoacoustic emission (DPOAE) growth functions reflect the active nonlinear cochlear sound processing when using a primary-tone setting which accounts for the different compressions of the two primaries at the DPOAE generation site and hence provide a measure for objectively assessing cochlear sensitivity and compression. DPOAE thresholds can be derived from extrapolated DPOAE input/output (I/O) functions independently of the noise floor and consequently can serve as a unique measure for reading DPOAE measurements. The thus-estimated DPOAE thresholds exhibit a close correspondence to behavior audiometric thresholds and thus can be used for reconstructing an audiogram, i.e., a DPOAE audiogram. The DPOAE I/O functions' slope increases with cochlear hearing loss and thus provides a measure for assessing recruitment. Hence, DPOAE I/O functions can give more information for diagnostic purposes than those of DP grams, transiently evoked OAEs (TEOAEs), or auditory brain stem responses (ABRs). DPOAE audiograms can be applied in pediatric audiology to assess cochlear dysfunction in a couple of minutes. In newborn hearing screening, they are able to detect transitory sound-conductive hearing loss and thus can help to reduce the rate of false-positive TEOAE responses in the early postnatal period. Since DPOAE I/O functions are correlated with loudness functions, DPOAEs offer the possibility of basic hearing aid adjustments, especially in infants and children. Extrapolated DPOAE I/O functions provide a tool for a fast automated frequency-specific and quantitative evaluation of hearing loss.

Audiometry, Evoked Response↗
PubMed1996

VISAUDIO: a Windows software application for Bekesy audiogram analysis and hearing research.

A Windows software system has been designed to facilitate hearing research programs and decision aid for epidemiological surveys in a military context. VISAUDIO provides graphical displays of audiograms with the results of various processing (smoothing, pathological patterns detection and classification), audiograms with pathological patterns like scotoms and recruitments are described (number, impaired frequencies, severity of loss for scotoms). Classical French ORL indexes are calculated (Index 42 which is the French legal index in occupational medicine, PAM or Lafon's index, IPA from the French norm NF S31-013 and IRB, a new occupational medicine index). An audiometric pattern classification is done for each audiogram using discriminant factorial analysis. The program allows audiogram comparisons on the same screen. The processing and analysis results can also be copied to any Windows software package via a PC clipboard. This prototype software is to be tested in a quasi real-time audiological information system comprising audiogram acquisition, processing, analysis and storage in a database. VISAUDIO software functions are illustrated with examples of screen displays.

Adult↗
PubMed2004

Feasibility of implementing a universal neonatal hearing screening programme using distortion product otoacoustic emission detection at a university hospital in Hong Kong.

OBJECTIVE: To assess the feasibility of implementing a universal neonatal hearing screening programme using distortion product otoacoustic emission detection at a major teaching hospital in Hong Kong. DESIGN: Descriptive study and questionnaire. SETTING. Teaching hospital, Hong Kong. METHODS: A total of 1064 infants, together with their mothers, were successfully recruited for the study. The participation rate was 99.3%. A three-stage hearing screening protocol using distortion product otoacoustic emission detection was adopted. Each of the participating infants was screened on three separate occasions (day 1-4, day 5-14, and day 21-30 after birth), irrespective of the test results. A questionnaire was administered to 364 randomly selected mothers to determine whether as consumers of the hearing screening service, mothers would find screening desirable. RESULTS: Results of the screening demonstrated an incidence of permanent bilateral hearing loss (>or=40 dB in the better ear) of 0.28%. The results also showed that 3.5% of the screened infants were referred for subsequent diagnostic audiological assessment, including those suspected with unilateral as well as bilateral hearing loss. Data obtained were comparable to other reported results obtained using multi-stage screening protocols. Taking both the false positive rate and the default rate into consideration, the most appropriate time for screening in this hospital setting appeared to be around day 5 to 14 when infants returned to the hospital's day centre as out-patients for routine medical follow-up. Since this day centre service is not generally provided by all maternity hospitals in Hong Kong, an alternative time for screening would be around day 21 to 30 when infants could return as out-patients solely for the hearing test. The results of the questionnaire suggested that most mothers thought a neonatal hearing screening would be desirable (91.35%). The majority (81.70%) indicated a preference for screening either within a few days of birth at the maternity ward prior to discharge from the hospital, or between 5 and 30 days when returning to the hospital as an out-patient. CONCLUSION: It was concluded that a universal neonatal hearing screening programme could be readily implemented in a maternity hospital setting in Hong Kong.

Clinical Protocols↗