Subcortical auditory system in tinnitus with normal hearing: insights from electrophysiological perspective.

PURPOSE: The mechanism of tinnitus remains poorly understood; however, studies have underscored the significance of the subcortical auditory system in tinnitus perception. In this study, our aim was to investigate the subcortical auditory system using electrophysiological measurements in individuals with tinnitus and normal hearing. Additionally, we aimed to assess speech-in-noise (SiN) perception to determine whether individuals with tinnitus exhibit SiN deficits despite having normal-hearing thresholds. METHODS: A total 42 normal-hearing participants, including 22 individuals with chronic subjective tinnitus and 20 normal individuals, participated in the study. We recorded auditory brainstem response (ABR) and speech-evoked frequency following response (sFFR) from the participants. SiN perception was also assessed using the Matrix test. RESULTS: Our results revealed a significant prolongation of the O peak, which encodes sound offset in sFFR, for the tinnitus group (p < 0.01). The greater non-stimulus-evoked activity was also found in individuals with tinnitus (p < 0.01). In ABR, the tinnitus group showed reduced wave I amplitude and prolonged absolute wave I, III, and V latencies (p ≤ 0.02). Our findings suggested that individuals with tinnitus had poorer SiN perception compared to normal participants (p < 0.05). CONCLUSION: The deficit in encoding sound offset may indicate an impaired inhibitory mechanism in tinnitus. The greater non-stimulus-evoked activity observed in the tinnitus group suggests increased neural noise at the subcortical level. Additionally, individuals with tinnitus may experience speech-in-noise deficits despite having a normal audiogram. Taken together, these findings suggest that the lack of inhibition and increased neural noise may be associated with tinnitus perception.

Subcortical Auditory Processing and Speech Perception in Noise Among Individuals With and Without Extended High-Frequency Hearing Loss.

PURPOSE: The significance of extended high-frequency (EHF) hearing (> 8 kHz) is not well understood so far. In this study, we aimed to understand the relationship between EHF hearing loss (EHFHL) and speech perception in noise (SPIN) and the associated physiological signatures using the speech-evoked frequency-following response (sFFR). METHOD: Sixteen young adults with EHFHL and 16 age- and sex-matched individuals with normal hearing participated in the study. SPIN performance in right speech-right noise, left speech-left noise, and binaural listening conditions was evaluated using the Turkish Matrix Test. Additionally, subcortical auditory processing was assessed by recording sFFRs elicited by 40-ms /da/ stimuli. RESULTS: Individuals with EHFHL demonstrated poorer SPIN performances in all listening conditions (p < .01). Longer latencies were observed in the V (onset) and O (offset) peaks in these individuals (p ≤ .01). However, only the V/A peak amplitude was found to be significantly reduced in individuals with EHFHL (p < .01). CONCLUSIONS: Our findings highlight the importance of EHF hearing and suggest that EHF hearing should be considered among the key elements in SPIN. Individuals with EHFHL show a tendency toward weaker subcortical auditory processing, which likely contributes to their poorer SPIN performance. Thus, routine assessment of EHF hearing should be implemented in clinical settings, alongside the evaluation of standard audiometric frequencies (0.25-8 kHz).

The prevalence of extended-spectrum beta lactamase-producing Escherichia coli and Klebsiella pneumoniae in clinical isolates and risk factors.

OBJECTIVE: To determine the prevalence of extended-spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli), risk factors of ESBL-producing strains and antimicrobial susceptibility pattern of ESBL-producing and non producing strains. METHODS: The study took place at the Faculty of Medicine, Osmangazi University, Eskisehir, Turkey from March to November 2002. We evaluated 100 K. pneumoniae and 100 E. coli strains isolated from various clinical specimens, as well as the patients from whom these strains were isolated. The double-disk synergy test was performed on the isolates for the detection of ESBL. We visited the patients with a growth of E. coli or K. pneumoniae or both from their clinical specimens in their wards if they were hospitalized, while the outpatients with a growth of these microorganisms were evaluated from their hospital records. RESULTS: The prevalence of ESBL-producing K. pneumoniae was 47% and E. coli was found as 12%. The ESBL-producing isolate rates were 50% (14/28) in intensive care units, 36.1% (35/97) in wards and 13.3% (10/75) in outpatients. Foley catheter (p<0.001), intravenous catheter (p<0.001), central venous catheter (p=0.002), intubation (p<0.001), surgery (p<0.001) and mechanical ventilation (p=0.002) were found as the risk factors for the acquisition of E. coli and K. pneumoniae with ESBLs. CONCLUSION: In our study, the prevalence of ESBL-producing isolates was high. The results of the study suggest that an antimicrobial policy and early removal of interventional apparatus be of importance for the control of ESBL-producing K. pneumoniae and E. coli.

Exacerbation of psoriasis due to peginterferon alpha-2b plus ribavirin treatment of chronic active hepatitis C.

A 45-year-old woman with chronic hepatitis C was treated with peginterferon alpha-2b in combination with ribavirin, which activated psoriasis. In the patient, psoriasis reoccurred after being inactive for 10 years. One week after institution of therapy, she presented with plaques of psoriasis at her injection site having been administered a first dose of peginterferon alpha-2b. Psoriatic lesions of the patient worsened dramatically during therapy. Cutaneous lesions appeared at the injection sites, in the face, the scalp hair, at the back of the ears, under the breasts and armpits, and in the regions of the anus and elbows. In the second week of treatment, transaminase levels of the patient regressed to normal. Detectable hepatitis C virus RNA in the serum was eliminated at week 14 of treatment. Because of the severity of psoriatic disease activity, therapy was discontinued at the end of 14 weeks after treatment onset. This side effect of peginterferon alpha-2b plus ribavirin treatment should be kept in mind in the treatment of patients with a history of psoriasis combined with active hepatitis C.