Influence of tinnitus sound therapy signals on the intelligibility of speech.

OBJECTIVE: To assess the influence on speech intelligibility of various signals used in tinnitus sound therapy. MATERIALS AND METHODS: We measured, in normal hearing subjects, the intelligibility of speech in the presence of three different sound therapy signals: wide-band noise, a recording of moving water, and a combination of tones. RESULTS: For a given level of stimulation, speech intelligibility was worst in the presence of wide-band noise, compared with the other sound therapy signals. When the stimulation level of the three different signals was increased, speech intelligibility deteriorated more rapidly with wide-band noise, compared with the other two signals. The combination of tones had the least influence on speech intelligibility. CONCLUSION: The use of different tinnitus sound therapy signals can lead to significantly different effects on the intelligibility of speech. The use of natural sound recordings or combinations of tones may provide the patient with more flexibility to change the stimulation level during treatment.

SUN-test (Speech Understanding in Noise): A Method for Hearing Disability Screening.

The SUN-test (Speech Understanding in Noise) is a speech-in-noise test to screen adults and older adults for hearing disability. The SUN-test consists in a short list of intervocalic consonants (VCV, vowel-consonant-vowel) in noise that are presented in a three-alternatives forced choice (3AFC) paradigm by means of a touch-screen interface. Based on the number of stimuli correctly identified, the tested subject gets one of three possible test outcomes: no listening difficulties, a hearing check would be advisable, or a hearing check is recommended. This paper reviews the main results obtained with the SUN-test in the Italian language in a population of nearly 1,300 adults and older adults with varying degrees of audiometric thresholds and audio-metric configurations, tested both in low and in high ambient noise settings. Results obtained in the tested population revealed that the outcomes of the SUN-test were in line with the outcomes of pure-tone testing, and that the test performance was similar both in low and in high ambient noise (up to 65 dB A). Results obtained with the SUN-test were not biased by the age of the subject because the performance of younger and older subjects in the test was similar. The mean duration of the SUN-test was nearly 40 s/ear, and was lower than 1 minute per ear even in subjects older than 80 years so that both ears could be tested, on average, in 2 minutes. The SUN-test was considered easy or slightly difficult by nearly 90% of subjects; test duration was judged short or fair by nearly 95% of subjects, and the overall evaluation of the test was pleasant, or neutral, in more than 90% of subjects. Overall, results of this study indicated that the SUN-test might be feasible for application in adult hearing screening. The test is fast, easy, self convincing, and reflects differences in hearing sensitivity between the tested subjects. The outcomes of the SUN-test were not influenced by the noise level in the test room (up to 65 dB A) indicating that the test, as such, might be feasible to screen adults and older adults both in clinical and in non clinical settings, such as convenient care clinics, hearing aid providers, or pharmacies, where the ambient noise is, typically, not controlled.

Pilot Initiatives of Adult Hearing Screening in Italy.

A series of pilot initiatives of adult hearing screening programs were organized in eight large and small-size cities in Italy in the past two years. The screening initiatives were held in public places, supermarkets, drugstores, and in some universities of the third age, and involved an overall population of 2,278 screened subjects with age ranging from 13 to 93 years. Three different screening tests were used to assess hearing ability in the participants, i.e.: screening pure tone audiometry (PTA), an automated speech-in-noise screening test (the SUN-test), and a screening questionnaire of self-perceived hearing handicap (the HHIE-S). This paper describes the organization and management of these screening initiatives and reviews the main results obtained in the screened population, using the three different screening tests. Results obtained in these pilot initiatives showed that screening adults for hearing problems might be feasible, on a local level, in non clinical settings and can be performed quite easily with the support of local coordinators and partners, such as associations or local authorities. It is recognized that further initiatives and studies will have to be performed to better define the key aspects related to the organization and management of adult hearing screening programs, either at a local, regional, or national level.

Influence of compact disk recording protocols on reliability and comparability of speech audiometry outcomes: acoustic analysis.

OBJECTIVE: To assess whether different compact disk recording protocols, used to prepare speech test material, affect the reliability and comparability of speech audiometry testing. MATERIAL AND METHODS: We conducted acoustic analysis of compact disks used in clinical practice, to determine whether speech material had been recorded using similar procedures. To assess the impact of different recording procedures on speech test outcomes, normal hearing subjects were tested using differently prepared compact disks, and their psychometric curves compared. RESULTS: Acoustic analysis revealed that speech material had been recorded using different protocols. The major difference was the gain between the levels at which the speech material and the calibration signal had been recorded. Although correct calibration of the audiometer was performed for each compact disk before testing, speech recognition thresholds and maximum intelligibility thresholds differed significantly between compact disks (p < 0.05), and were influenced by the gain between the recording level of the speech material and the calibration signal. CONCLUSION: To ensure the reliability and comparability of speech test outcomes obtained using different compact disks, it is recommended to check for possible differences in the recording gains used to prepare the compact disks, and then to compensate for any differences before testing.

Assessment of SAR in the tissues near a cochlear implant exposed to radiofrequency electromagnetic fields.

Cochlear implants (CI) are electronic devices used to restore partial hearing to people with severe hearing impairment. This paper aims to investigate if the introduction of a CI has an effect on SAR distribution in a head model exposed to radiofrequency electromagnetic fields (RF EMF) at mobile communication frequencies. The head model was obtained by image segmentation, the implant was modelled as a geometric structure and the exposure source was modelled as a uniform plane wave at 900 MHz, 1750 MHz and 1950 MHz, incident on the side of the head with the CI. Vertical and horizontal polarizations were simulated. Results show that the presence of a CI inside the cochlea produces negligible variations in the averaged SAR values, both in the head and in the cochlear tissues, although very localized differences in point SAR were found in the cochlea. Globally, these results suggest that finding harmful effects in the cochlear tissues will be unlikely.

Influence of cochlear implant-like operating conditions on wavelet speech processing.

This study assessed the influence of 'non-ideal' operating conditions typical of cochlear implants (CIs) on the behavior of the wavelet transform (WT) when used to process speech. Particular attention was given to the effect of limited stimulation rate and limited number of channels, typical of CI speech processing, on the performance of the WT. Computer simulations and psychoacoustic recognition tests of WT-processed speech were implemented. The crucial role played by the 'non-ideal' operating conditions on WT speech processing was put in evidence. Psychoacoustic recognition tests proved to be fundamental to evaluate feasibility of WT speech processing for CIs.