Tinnitus: from cortex to cochlea

Het medische woord voor oorsuizen is tinnitus. Tinnitus is het waarnemen van geluid, waar geen bron voor is. Het kan dus alleen worden waargenomen door de persoon zelf en niet door anderen. De meeste volwassenen hebben wel eens last gehad van tijdelijke tinnitus. Tinnitus kan echter ook blijvend zijn. Geschat wordt dat permanente tinnitus bij 8-20% van de mensen in de algemene bevolking voorkomt, waarbij de meeste mensen goed met deze klacht kunnen omgaan. Echter, 1-3% van de mensen met tinnitus heeft zoveel klachten dat ze medische hulp zoeken. De oorzaak van tinnitus is nog niet bekend. Momenteel gaat men ervan uit dat bij tinnitus veranderingen in de centrale hersengebieden, inclusief de hersengebieden die betrokken zijn bij horen, een bepalende rol spelen bij het ontstaan van tinnitus. Het ontstaan wordt waarschijnlijk vooraf gegaan door een vorm van schade aan het gehoor of gehoororgaan. Deze schade zorgt dan voor de veranderingen in het brein. Dit proefschrift beschrijft het onderzoek dat is gedaan naar de oorzaak van tinnitus. Hierbij is extra nadruk gelegd op de zenuwbanen van hersengebieden die bij horen betrokken zijn. De oorzaak van tinnitus is helaas nog steeds niet ontrafeld. Wel is duidelijk geworden dat links-rechts verschillen in het brein die eerder aan tinnitus werden toegeschreven, ook bij gezonde proefpersonen voorkomen. We hebben geen afwijkingen in functioneren kunnen vinden in specifieke zenuwbanen die van de hersenstam naar het oor lopen. Om dit ingewikkelde systeem van zenuwbanen verder te onderzoeken, doen we meerdere suggesties voor nieuwe onderzoeken. Tinnitus is known as “ringing in the ears”. Tinnitus is the perception of a meaningless sound without an external source. Tinnitus cannot be heard by others. Transient tinnitus is experienced by almost all adults at some point in their life. Tinnitus can also be permanent, which is the case in 8-20% of the general population. Up to 1-3% of the people with tinnitus are severely affected by it and seek medical attention. The pathophysiology of tinnitus is not known. Tinnitus is currently considered to involve central phenomenon in the brain including auditory areas, although some form of cochlear or hearing damage probably initiates the neuroplastic changes in the brain, that results in tinnitus. This thesis concerns the pathophysiology of tinnitus, with special emphasis on the efferent part of the central auditory system. The efferent auditory system runs from the auditory cortex to the cochlea, connecting all auditory regions along its path. Unfortunately, we did not discover the cause of tinnitus. However, we did find that the previously reported asymmetries in metabolism of auditory brain areas is also present in healthy people and that this is not associated with tinnitus. We tested the efferent auditory system at the level of the brain stem and did not find abnormalities in its functioning. To explore the complex system of the entire efferent auditory system we made several suggestions for future research to investigate the role of the efferent auditory system in the pathophysiology of tinnitus.

Giant Cholesteatoma: Recommendations for Follow-up

This report presents the management of five patients who presented with giant recurrent or residual cholesteatoma after periods of 2 to 50 years. Their case histories are highly diverse, but all provide evidence of the need for long-term follow-up

Vascular thoracic outlet syndrome. Longer posterior rib stump causes poor outcome

Objective: To assess the role of the relative length of the posterior rib stump in outcome after transaxittary first rib resection for thoracic outlet syndrome. Methods: All patients with a transaxittary first rib resection between January 1990 and February 2004 were selected. Relative rib stump length was calculated by dividing the length of the posterior rib stump by the height of the 10th thoracic vertebra. Measurements were made on postoperative X-rays. Outcome was defined as excellent, good, fair, or poor. Results: Surgical outcome was excellent in 11 procedures (28.2%), good in 12 procedures (30.8%), fair in 9 (23.1%), and poor in 7 procedures (17.9%). Correlation of the outcome with the relative rib stump length gives a coefficient of .374 (P = .02). After exclusions of 3 patients with other medical conditions explanatory for remaining pain in the operated limb, the correlation coefficient was .614 (P <.01). Conclusion: The relative length of the posterior rib stump is correlated with the outcome after transaxittary first rib resection in patients with thoracic outlet syndrome. First rib resection in patients with proven vascular compression should be as close as possible to the articulation with the transverse process, without injuring the brachial plexus. (c) 2006 Elsevier B.V. All rights reserved

Plasticity in tinnitus patients:a role for the efferent auditory system?

Hypothesis: The role of the corticofugal efferent auditory system in the origin or maintenance of tinnitus is currently mostly overlooked. Changes in the balance between excitation and inhibition after an auditory trauma are likely to play a role in the origin of tinnitus. The efferent auditory system can be expected to be involved in such changes. Background: The goal of this article was to investigate the current knowledge of the functional efferent auditory system in humans, mostly based on animal research, and to look for new possibilities to try to answer the question of the specific role(s) of the corticofugal efferent auditory system in tinnitus. Methods: Literature review. Results: Several suggestions for future research are made, for studies in humans as well as in animals. Conclusion: We think that it will be worthwhile to investigate the efferent auditory system and its relations to tinnitus in the near future. With this article, we hope to inspire such work

Contralateral Suppression of Otoacoustic Emissions in Tinnitus Patients

Objective: To compare the functioning of the medial olivocochlear efferent system between tinnitus patients and control subjects. Study Design: Prospective, nonrandomized controlled analysis of suppression of otoacoustic emissions with contralateral acoustic stimulation. Setting: Tertiary referral center. Patients: Initial analysis of 97 tinnitus patients and 44 control subjects with click-evoked otoacoustic emission measurement. If subjects had reproducible otoacoustic emissions at 80 dB SPL, suppression of otoacoustic emission with contralateral acoustic stimulation was measured with a 65-dB click stimulus. This resulted in inclusion of 44 ears of tinnitus patients and 57 ears of control subjects. Intervention: Suppression of the otoacoustic emissions generated by the 65-dB click stimulus was tested using contralateral broadband noise at 70 dB SPL. Suppression was calculated in half-octave frequency bands centered at 1.0, 1.4, 2.0, 2.8, and 4.0 kHz. Main Outcome Measure: The amount of suppression of the OAE, calculated in half-octave frequency bands. Results: Otoacoustic emission amplitudes were equal in both groups. Contralateral suppression of the signal was found in both patients and controls. The amount of suppression was equal, except for the 2.0- and 2.8-kHz frequency bands in the right ear (p value of 0.03, 0.008, respectively), for which the patients had less suppression. Conclusion: The suppression of otoacoustic emissions with CAS seems equally effective in tinnitus patients and healthy controls. The minor differences between both groups suggest subtle differences in the function of the medial olivocochlear efferent system

Wavelet analysis demonstrates no abnormality in contralateral suppression of otoacoustic emissions in tinnitus patients

The efferent auditory system is thought to play a role in the origin of tinnitus. Part of this system can be tested in humans with contralateral suppression of otoacoustic emissions. Stimulation of the medial olivocochlear efferent system is responsible for this reduction of otoacoustic emissions after contralateral acoustic stimulation. Previous research on patients with tinnitus showed inconclusive results. With wavelet analysis both time and frequency information of the emission can be analysed and compared. Contralateral suppression of otoacoustic emissions was therefore measured in tinnitus patients (n = 26) and normal subjects (n = 37) and analysed using wavelets. No significant difference in suppression was found between the tinnitus patients and the control group. (C) 2012 Elsevier B.V. All rights reserved

Data from an international multi-centre study of statistics and mathematics anxieties and related variables in university students (the SMARVUS dataset)

This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts. Data and metadata are stored on the Open Science Framework website [https://osf.io/mhg94/]