Active listening to tinnitus and its relation to resting state EEG activity.

Chronic subjective tinnitus is an audible sound that lacks an external source. A notable number of neuroscientific studies have been conducted applying magnetoencephalography and electroencephalography (MEEG) in resting state paradigms to elucidate neural correlates of tinnitus. In these studies, recordings were usually performed without particular instructions to the participant. Thus, it remains unclear whether resulting MEEG measures may have been affected by attention on the actual tinnitus percept. In order to investigate this potential source of variance in tinnitus MEEG resting state results, we investigated the difference between non-instructed resting state (RS) and active listening to tinnitus (AL) using questionnaires as well as EEG power analysis (n = 45). Questionnaire scores for the two conditions resulted in significant increases in tinnitus distress and presence during AL. Beyond that, no differences in EEG band power were found between the conditions both on the sensor and source levels. Results point to an expected increased tinnitus presence and distress in the AL condition on the behavioral level. These behavioral changes are not reflected in changes in EEG oscillatory power, which is especially surprising when looking at the alpha band related to general external and internal attentional processes. Furthermore, no changes in other frequency bands (delta, theta, beta, gamma) attributed to aspects of tinnitus distress, loudness, and maintenance were observed. In conclusion, the absence of EEG power changes between conditions may be in support of a chronic and invariant state of altered MEEG signatures in tinnitus. Further studies are needed to better elucidate MEEG resting state paradigms in tinnitus.

Cochlear implants in single-sided deafness - clinical results of a Swiss multicentre study.

AIM OF THE STUDY: The aim of this multicentre, prospective, open, nonrandomised clinical trial was to demonstrate the clinical efficiency and outcomes of cochlear implants (CIs) in adult patients with post-lingual single-sided deafness (SSD). METHODS: A group of five left and five right SSD participants were investigated with various clinical tests and questionnaires before and 12 months after CI activation. Changes in hearing thresholds, speech understanding in noise, sound localisation, tinnitus (Tinnitus Handicap Inventory; THI), subjective hearing ability (Speech, Spatial and Qualities of Hearing Scale; SSQ), and quality of life (WHOQOL-BREF) were assessed. In addition, the pre- and postoperative results of the SSD patients were compared with an age- and gender-matched normal hearing control group. RESULTS: Surgery was uncomplicated in all patients. Two years after implantation, 9 of the 10 patients used their CI regularly for an average of more than 11 hours a day. A significant improvement in speech understanding in noise measured in the sound field using the Oldenburg sentence test could be demonstrated in the two situations in which patients with SSD experience the greatest difficulty: speech from the front and noise at the healthy ear, and speech to the implanted ear and noise from the front. The sound localisation test showed significant improvement of the mean localisation error and the root mean square error after CI activation. Furthermore, a significant reduction of the THI was measured, and the SSQ showed a significant improvement in the subscale speech comprehension and in the subscale spatial hearing. Also, quality of life measured with the WHOQOL-BREF showed a general improvement, which was significant in the global subscale. For this questionnaire, there was no significant difference between the normal-hearing control group and the patients after 12 months of CI use. CONCLUSION: This study confirmed the clinical benefit of cochlear implantation in patients with SSD. The significant improvement of speech understanding in noise, sound localisation, tinnitus perception, subjective hearing ability, and in particular the improved quality of life support the recommendation that patients with recently acquired SSD should be offered a CI. (Clinical trial registration number on clinicaltrial.gov: NCT01749592).

EEG oscillatory power dissociates between distress- and depression-related psychopathology in subjective tinnitus.

Recent research has used source estimation approaches to identify spatially distinct neural configurations in individuals with chronic, subjective tinnitus (TI). The results of these studies are often heterogeneous, a fact which may be partly explained by an inherent heterogeneity in the TI population and partly by the applied EEG data analysis procedure and EEG hardware. Hence this study was performed to re-enact a formerly published study (Joos et al., 2012) to better understand the reason for differences and overlap between studies from different labs. We re-investigated the relationship between neural oscillations and behavioral measurements of affective states in TI, namely depression and tinnitus-related distress by recruiting 45 TI who underwent resting-state EEG. Comprehensive psychopathological (depression and tinnitus-related distress scores) and psychometric data (including other tinnitus characteristics) were gathered. A principal component analysis (PCA) was performed to unveil independent factors that predict distinct aspects of tinnitus-related pathology. Furthermore, we correlated EEG power changes in the standard frequency bands with the behavioral scores for both the whole-brain level and, as a post hoc approach, for selected regions of interest (ROI) based on sLORETA. Behavioral data revealed significant relationships between measurements of depression and tinnitus-related distress. Notably, no significant results were observed for the depressive scores and modulations of the EEG signal. However, akin to the former study we evidenced a significant relationship between a power increase in the ß-bands and tinnitus-related distress. In conclusion, it has emerged that depression and tinnitus-related distress, even though they are assumed not to be completely independent, manifest in distinct neural configurations.

The role for dickkopf-homolog-1 in the pathogenesis of Crohn's disease-associated fistulae.

BACKGROUND: One of the most challenging conditions in Crohn's disease (CD) patients is the treatment of perianal fistulae. We have recently shown that epithelial-to-mesenchymal transition (EMT) plays a crucial role during CD-fistulae development. Dickkopf-homolog 1 (DKK-1) is known to play a key role during EMT. Here, we investigated a role for DKK-1 in the pathogenesis of CD-associated fistulae. METHODS: Dkk-1 protein expression in CD-fistula specimens were investigated by immunohistochemistry. Colonic lamina propria fibroblasts (CLPF) were obtained from either non-IBD control patients or patients with fistulizing CD. HT-29 intestinal epithelial cells (IEC) were either grown as monolayers or spheroids. Cells were treated with either TNF-α, TGF-ß or IL-13. Knock-down of DKK-1 or ß-Catenin was induced in HT-29-IEC by siRNA technique. mRNA expression was determined by real-time-PCR. RESULTS: Dkk-1 protein was specifically expressed in transitional cells lining the fistula tracts. TGF-ß induced DKK-1 mRNA expression in HT-29-IEC, but decreased it in fistula CLPF. On a functional level, DKK-1 knock-down prevented TGF-ß-induced IL-13 mRNA expression in HT-29-IEC. Further, loss of ß-Catenin was accompanied by reduced levels of DKK-1 and, again, IL-13 in IEC in response to TGF-ß. In turn, treatment of HT-29-IEC as well as fistula CLPF with IL-13 resulted in decreased levels of DKK-1 mRNA. Treatment with TNF-α or the bacterial wall component, muramyl-dipeptide, decreased DKK-1 mRNA levels in HT-29-IEC, but enhanced it in fistula CLPF. DISCUSSION: We demonstrate that DKK-1 is strongly expressed in cells lining the CD-fistula tracts and regulates factors involved in EMT initiation. These data provide evidence for a role of DKK-1 in the pathogenesis of CD-associated perianal fistulae.