Search

The cochlear microphonic is a receptor potential believed to be generated primarily by outer hair cells. Its detection in surface recordings has been considered a distinctive sign of outer hair cell integrity in patients with auditory neuropathy. This report focuses on the results of an analysis performed on cochlear microphonic recorded by transtympanic electrocochleography in response to clicks in 502 subjects with normal hearing threshold or various degrees of hearing impairment, and in 20 patients with auditory neuropathy. Cochlear microphonics recorded in normally-hearing and hearing-impaired ears showed amplitudes decreasing by the elevation of compound action potential Cochlear microphonic responses were clearly detected in ears with profound hearing loss. After separating recordings according to the presence or absence of central nervous system pathology (CNS+ and CNS-, respectively), cochlear microphonic amplitude was significantly higher in CNS+ than in CNS- subjects with normally-hearing ears and at 70 dB nHL compound action potential threshold. Cochlear microphonic responses were detected in all auditory neuropathy patients, with similar amplitudes and thresholds to those calculated for normally-hearing CNS- subjects. Cochlear microphonic duration was significantly higher in auditory neuropathy and normally-hearing CNS+ patients compared to CNS- subjects. Our results show that: 1. cochlear microphonic detection is not a distinctive feature of auditory neuropathy; 2. CNS+ subjects showed enhancement in cochlear microphonic amplitude and duration, possibly due to efferent system dysfunction; 3. long-lasting, high frequency cochlear microphonics with amplitudes comparable to those obtained from CNS- ears were found in auditory neuropathy patients. This could result from a variable combination of afferent compartment lesion, efferent system dysfacilitation and loss of outer hair cells.

The purpose of the work was to determine the feasibility of direct nursery DPOAE testing in a universal hearing screening, evaluate the results and calculate the reliability of this test vs. Auditory Brainstem Responses (ABR). To this purpose DPOAE (sweep and I/O test) were performed on 500 children born between January and August 1996 at the Civil Hospital of Mestre, Italy. All the children were examined in the nursery, no matter what the risk factors or specific motivations. Besides determining whether the examination could be performed, its specificity and sensitivity, the time required and any variation depending on the day of testing were also evaluated. In a high percentage of cases (11.2%) it proved impossible to perform the test. In addition, when compared to ABR, the percentage of false positives was rather high (16.2%) and specificity was 84%. As conceived, the test requires 6'09" per ear. Comparison of the differences in results according to day of execution did not appear significant although there was a lower percentage of false positive after the third day of life. DPOAE can be measured in the nursery. The high number of false positives and the frequent need to repeat the measurements, however, increase the amount of time required for this test, thus voiding any time savings over an ABR screening: a test which is rather lengthy by provides a high degree of specificity.

This study evaluates the exposure of newborn babies in neonatal intensive care units (NICU) to noise which can cause hearing lesions directly (acoustic trauma) as well as indirectly (hypoxia). Moreover, noise can have an aggravating effect when combined with other potentially harmful factors in the NICU, such as ototoxic medication or stress due to other external stimuli, such as excessively bright light, lack of a day/night rhythm or pain. Sound pressure levels were measured in the NICU and inside the cribs in various experimental conditions, classified under 3 different types of sound events: constant background noise, variations in background noise and impulsive events. The main sources of noise detected were crib noise generated by ventilation and temperature control systems, ambient noise in the room, noise caused by the staff in the NICU, noise generated by crib alarm systems and NICU apparatus and noise caused by activity on the crib cover or on its plexiglas top. Findings revealed that the influence of ambient noise is fairly irrelevant. Background noise and its variations concerned with activities in the department never exceeded the limits considered potentially harmful to adults (DRC), whereas the impulsive noise generated by staff on the cribs or on the plexiglas tops was considerable and potentially harmful. These findings demonstrate that it is feasible and relatively easy to control noise in the NICU and significantly reduce the impulsive noise component by training staff to be more careful and avoid any unnecessary jolting and rough handling on and near the cribs.

This study analyzed 73 electrocochleographic recordings made in children with a normal hearing threshold, selected retrospectively from 1563 recordings made between 1973 and 1990. The aim of the study was to check the original findings for any correlation between the various response parameters which might be indicative of a pathological condition. Compound action potential (AP) latency and amplitude, presynaptic summation potential (SP) and cochlear microphonic (CM) amplitudes and AP rapid adaptation behavior were calculated and recordings were associated with clinical information on aetiologic diagnosis, otoscopic examination, impedance measurement data and the finding of any central nervous system (CNS) pathology. The trend of the amplitudes as a function of the intensity of all three potentials (input-output functions), CM and SP in particular, demonstrated unexpected scattered values especially towards the high intensities. This was found correlated to the presence of CNS pathology. The comparison between the two groups (with vs without CNS pathology) with the aid of the Student's t-test proved statically significant, especially for CM and SP amplitudes while rather less so for AP amplitude. In particular, all CM and SP amplitude values outside the confidence intervals (calculated as 95% of normal cases) revealed CNS pathology. It has been suggested that the influence of the CNS on cochlear function is due to a disturbed function of the olicocochlear bundle, which is known to have an inhibitory effect on cochlear dynamics; furthermore, there is also proof that it can be activated regardless of any ipso-and/or contra-lateral acoustic stimulation. The effects observed on the electrocochleography in cases with CNS disorders would thus be explained by an interruption of the olivocochlear bundle at the CNS level or a disruption of the CNS mechanism capable of controlling its activation.

Bisyllabic words are the most frequently used italian speech material in evaluating intelligibility function. The italian words presently used are those proposed by Bocca and Pellegrini in 1950. The Lists of these words do, however, present some problems with regard to phonemic balance and word familiarity. In speech audiometry testing, Lists are considered interchangeable if each individual List has the same phonemic balance. So as to avoid incorrect identification due to incomprehension of infrequently used words, we chose 200 of the most familiar bisyllabic words from the most recent, widely used occurrence vocabulary of the Italian Language. Secondly, we proceeded with phonemic balance of the speech material. The selected words were divided into ten lists of 20 words each, arranged in order to obtain the best phonemic balance within each individual List and among different Lists. The differences between the new and old speech material are presented and discussed.

Vestibular nystagmus induced by caloric stimulation (20 degrees and 44 degrees C) was evaluated in terms of duration, frequency and slow phase velocity in 80 patients suffering from clinically defined multiple sclerosis. Criteria of abnormality were established with reference to 3 confidence levels from normative data of a 15-subject control group. Abnormal data representative of vestibular hypo- and hyperreflexia were found ranging between 27 and 53% depending on different parameters and diagnostic criteria. Significant differences in occurrence of nystagmus abnormalities became evident by analyzing 6 different windows of the vestibular response. Different distributions of hypo- and hyperreflexia were observed in relation to the time-course of the normal cumulative response curve, as well as to different stimulus temperatures. For each subject the abnormal data of the 2 stimulated ears X 2 caloric stimulations X 6 analysis windows were cumulated, yielding an overall outcome of pathological results in 66% to 90% of the patients, depending on the different diagnostic criteria.

The lesion location (cochlear vs. retrocochlear) of sensorineural hearing loss may be differentiated with a diagnostic index (delta V), which is calculated from the wave V latency of the monaurally evoked auditory brainstem response (ABR), and from the pure-tone hearing threshold at 2 and 4 kHz. The delta V values obtained from 80 recruiting ears have proven to correlate linearly to the amount of the hearing loss, hence allowing to define appropriate confidence boundaries for cochlear hearing losses. In contrast, the delta V values obtained from 32 ears of patients with retrocochlear lesions--cerebellopontine angle (CPA) tumors--were all found to exceed the 95% upper confidence limits projected for cochlear lesions, thus giving a 100% rate of true results in the detection of retrocochlear pathology. These results, providing an ABR parametric model for the cochlear hearing loss, suggest a diagnostic strategy for the early detection of CPA tumors based on the exclusion of a cochlear hearing loss.

Eustachian tube (ET) primary tumors and tumor-like lesions are rare diseases presenting with common ear, nose and throat symptoms. Pathology can range from developmental anomalies to high malignant neoplasms. Hence this review aimed at suggesting a classification and outline relevant aspects of ET primary tumors and tumor-like lesions, describing clinical findings, diagnostic management and therapeutic approaches. MEDLINE, CINAHL, OVIDSP, HIGHWIRE, and GOOGLE databases were searched from inception to July 2011 for relevant studies. Further papers were identified by examining the reference lists of all included. Sixty-five papers met the inclusion criteria, enclosing 78 cases. Case reports are increasing in the past few years. Benign lesions and tumor-like lesions of ET have been reported. Moreover, melanomas, carcinomas, and sarcomas can affect the ET as a primary site.