Repeated audiometry after bacterial meningitis: Consequences for future management

Objective: Sensorineural hearing loss is a common sequela of bacterial meningitis. The objective of this study is to delineate the incidence and course of hearing loss after bacterial meningitis. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Data of 655 patients who suffered from bacterial meningitis between 1985 and 2015 were analyzed. Interventions: None. Main Outcome Measurements: Availability of audiometric data, incidence of hearing loss, and onset and course of hearing loss. Results: In this cohort the incidence of hearing loss (>25 dB) was 28% (95% confidence interval 23-34%). The incidence of profound hearing loss (>80 dB) was 13% (95% confidence interval 10-18%). Normal hearing at the first assessment after treatment for meningitis remained stable over time in all these patients. In 19 of the 28 patients with diagnosed hearing loss, the hearing level remained stable over time. Hearing improved in six patients and deteriorated in two patients. One patient showed a fluctuating unilateral hearing loss. Conclusion: Audiological tests in patients with bacterial meningitis, especially children, should be started as soon as possible after the acute phase is over. As we found no deterioration of initial normal hearing after bacterial meningitis, repeated audiometry seems indicated only for those with diagnosed hearing loss at first assessment

The orbit space of groupoids whose C∗C^*-algebras are GCR

Let $G$ be second countable locally compact Hausdorff groupoid with a continuous Haar system. We remove the assumption of amenability in a theorem by Clark about GCR groupoid $C^*$-algebras. We show that if the groupoid $C^*$-algebra of $G$ is GCR then the orbits of $G$ are locally closed.Comment: 1

Functional sex differences in human primary auditory cortex

Background We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a baseline (no auditory stimulation). Results and discussion We found a sex difference in activation of the left and right PAC when comparing music to noise. The PAC was more activated by music than by noise in both men and women. But this difference between the two stimuli was significantly higher in men than in women. To investigate whether this difference could be attributed to either music or noise, we compared both stimuli with the baseline and revealed that noise gave a significantly higher activation in the female PAC than in the male PAC. Moreover, the male group showed a deactivation in the right prefrontal cortex when comparing noise to the baseline, which was not present in the female group. Interestingly, the auditory and prefrontal regions are anatomically and functionally linked and the prefrontal cortex is known to be engaged in auditory tasks that involve sustained or selective auditory attention. Thus we hypothesize that differences in attention result in a different deactivation of the right prefrontal cortex, which in turn modulates the activation of the PAC and thus explains the sex differences found in the activation of the PAC. Conclusion Our results suggest that sex is an important factor in auditory brain studies

Activation in primary auditory cortex during silent lipreading is determined by sex

Recent studies investigating whether the primary auditory cortex (PAC) is involved in silent lipreading gave inconsistent results. We used positron emission tomography to identify which areas in the temporal lobe process visible speech, with a focus on the PAC. Subjects were tested on lipreading numbers and only the best lipreaders were included in the study (n = 18; 9 female, 9 male). Each subject was scanned while either watching a movie with a speaker silently articulating numbers ( lipreading condition) or watching a static image of the same speaker ( baseline condition). Subjects were instructed to repeat internally the number seen or the number '1'. Compared to the baseline condition, silent lipreading activated temporal areas in both hemispheres with the largest activation clusters in the left hemisphere. When the whole group was examined, no activation in the PAC was found. But when investigating the two sexes separately, the female group demonstrated activation of the left PAC. There was no significant activation in the right female PAC or in the left and right male PAC. Since both groups had similar performances in lipreading, differential activity in the PAC has no effect on lipreading scores. These results may explain previous inconsistent results where no differentiation for sex was made. Copyright (c) 2007 S. Karger AG, Basel

Neural responses to silent lipreading in normal hearing male and female subjects

In the past, researchers investigated silent lipreading in normal hearing subjects with functional neuroimaging tools and showed how the brain processes visual stimuli that are normally accompanied by an auditory counterpart. Previously, we showed activation differences between males and females in primary auditory cortex during silent lipreading, i.e. only the female group significantly activated the primary auditory region during lipreading. Here we report and discuss the overall activation pattern in males and females. We used positron emission tomography to study silent lipreading in 19 normal hearing subjects (nine females). Prior to scanning, subjects were tested on their lipreading ability and only good lipreaders were included in the study. Silent lipreading was compared with a static image. In the whole group, activations were found mainly in the left hemisphere with major clusters in superior temporal, inferior parietal, inferior frontal and precentral regions. The female group showed more clusters and these clusters were larger than in the male group. Sex differences were found mainly in right inferior frontal and left inferior parietal regions and to a lesser extent in bilateral angular and precentral gyri. The sex differences in the parietal multimodal region support our previous hypothesis that the male and female brain process visual speech stimuli differently without differences in overt lipreading ability. Specifically, females associate the visual speech image with the corresponding auditory speech sound whereas males focus more on the visual image itself