Tinnitus and mobile phone use.

OBJECTIVES: The mechanisms that produce tinnitus are not fully understood. While tinnitus can be associated with diseases and disorders of the ear, retrocochlear diseases and vascular pathologies, there are few known risk factors for tinnitus apart from these conditions. There is anecdotal evidence of an link between mobile phone use and tinnitus, but so far there have been no systematic investigations into this possible association. METHODS: 100 consecutive patients presenting with tinnitus were enrolled in an individually matched case-control study. For each case a control subject was randomly selected from visiting outpatients matched for sex and age. The patient's history was obtained and clinical examinations were conducted to exclude patients with known underlying causes of tinnitus. Mobile phone use was assessed based on the Interphone Study protocol. ORs were computed by conditional logistic regression with years of education and living in an urban area as covariates. RESULTS: Mobile phone use up to the index date (onset of tinnitus) on the same side as the tinnitus did not have significantly elevated ORs for regular use and intensity or for cumulative hours of use. The risk estimate was significantly elevated for prolonged use (≥4 years) of a mobile phone (OR 1.95; CI 1.00 to 3.80). CONCLUSIONS: Mobile phone use should be included in future investigations as a potential risk factor for developing tinnitus.

Effects of fine structure and extended low frequencies in pediatric cochlear implant recipients.

OBJECTIVE: In recent years, new speech coding strategies have been developed with the aim of improving the transmission of temporal fine structure to cochlear implant recipients. This study reports on the implementation of one such strategy (fine structure processing, FSP) in children. METHODS: This was a prospective study investigating the upgrade to a new speech processor. The upgrade used a repeated measures design with an alternating order of conditions (A-B-A-B design). Twelve pre- and perilingually deaf children with MED-EL C40+ cochlear implants were enrolled in the study. Patients were upgraded from their Tempo+ speech processor, which used continuous interleaved sampling (CIS) in combination with a frequency spectrum of 200-8500 Hz, to an Opus speech processor, which used FSP with an extended frequency spectrum of 70-8500 Hz. The primary means of testing was an HSM (Hochmair, Schulz and Moser) sentence test at 65 and 80 dB in quiet. In addition, the "Mainzer Kindersprachtest" (Mainz audiometric speech test for children) was applied at 65 and 70 dB. RESULTS: When the new FSP speech processor was used together with the extended low frequency range, HSM sentence tests at 65 and 80 dB resulted in scores indicating statistically significant improvements of 7.1 and 9.9 percentage points, respectively. Scores in the "Mainzer Kindersprachtest" at 65 and 70 dB indicated statistically significant improvements of 9.3 and 6.1 percentage points, respectively. CONCLUSIONS: The present study clearly shows that children benefit from the fine structure speech coding strategy in combination with an extended frequency spectrum in the low frequencies, as is offered by the Opus speech processors. This should be taken into consideration when fitting pre- and perilingually deaf children implanted almost a decade previously.

Combined analysis of audiologic performance and the plasma biomarker stromal cell-derived factor 1a in type 2 diabetic patients.

OBJECTIVE: This study presents a potentially novel method of screening for pathogenetic factors in diabetic audiopathy by comparing the absolute plasma concentration of a microangiopathy biomarker, stromal cell-derived factor 1a (SDF-1a), with frequency-specific audiometric results. BACKGROUND: Impaired hearing function in diabetic patients has, to date, remained a controversial and poorly understood theme with sparse clinical data. This is in contrast to more established components of the disease such as diabetic retinopathy, where diabetic microangiopathy is thought to be of pathogenetic relevance, and specific molecules such as SDF-1a have been assigned a relevant role. CLINICAL SETTING: Out patient clinic, Vienna General Hospital, Medical University of Vienna. PATIENTS: 18 Type 2 diabetic patients and 18 nondiabetic controls. MATERIALS AND METHODS: Pure-tone audiometry and Freyburger number tests were used to evaluate hearing function. Blood plasma values of SDF-1a were analyzed using an enzyme-linked immunosorbent assay. Statistical comparison of functional audiometric data and the absolute SDF-1a values was performed for all frequencies. RESULTS: A significantly higher plasma SDF-1a concentration (p < 0.005) in Type 2 diabetic patients, who also presented with higher pure-tone audiometry thresholds compared with nondiabetic subjects, was noted. Furthermore, an association between SDF-1a and audiometric performance, body mass index, and duration of diabetes was observed. CONCLUSION: We hypothesize that diabetic microangiopathy and its biomarker SDF-1a should be considered as potential pathogenetic factors for altered diabetic hearing, warranting further investigation.