Lateral trunk flexion (LTF) is a common phenomenon in patients with Parkinson’s disease (PD) and has recently been associated with peripheral vestibular dysfunction. Since deviation of the subjective ...visual vertical (SVV) is a well-recognized feature of disorders involving vestibular processing, we analyzed SVV angles in 30 PD patients with and without LTF to assess the possible role of vestibular dysfunction in the pathogenesis of LTF in PD. Quantification of SVV was obtained using a simple bedside test. PD patients with LTF had significantly greater SVV angles as compared to PD patients without LTF (median: 4.3° range: 0.1–17.7, n=21, versus 0.8° 0.1–1.9, n=9; p<0.001). 14 of 21 patients with LTF showed pathological SVV, while all 9 patients without LTF had normal SVV. Abnormal SVV was more frequent when LTF was reversible in the supine position compared to fixed LTF. In a subgroup of PD patients with LTF, pathological SVV suggests vestibular dysbalance, which might be involved in the pathophysiological mechanisms underlying LTF.
A noise trauma induces central nervous system pathologies, which generate deficits in hearing and perception of sound.
Are degenerative mechanisms in the central auditory system a direct impact of ...overstimulation or an effect of acoustic deprivation?
Detection of cell death in a mouse model of noise-induced hearing loss at different times after single or repeated noise exposure.
A single noise exposure (3 h, 115 dB SPL, 5-20 kHz) induces acute (≤1 day) and long-term (observation period 14 days) degeneration, particularly in subcortical structures. Repeated noise trauma is followed by pathologies in the auditory thalamus and cortex.
Noise has a direct impact on basal structures of the central auditory system; a protection of cortical areas is possibly due to inhibitory neuronal projections. Degenerative mechanisms in higher structures of the pre-damaged system point to an increased impairment of complex processing of acoustic information.
The cytokine transforming growth factor beta (TGFβ) has a role in regulating the normal and pathological response to wound healing, yet how it shifts from a pro-repair to a pro-fibrotic function ...within the wound environment is still unclear. Using a clinically relevant ex vivo post-cataract surgery model that mimics the lens fibrotic disease posterior capsule opacification (PCO), we investigated the influence of two distinct wound environments on shaping the TGFβ-mediated injury response of CD44+ vimentin-rich leader cells. The substantial fibrotic response of this cell population occurred within a rigid wound environment under the control of endogenous TGFβ. However, TGFβ was dispensable for the role of leader cells in wound healing on the endogenous basement membrane wound environment, where repair occurs in the absence of a major fibrotic outcome. A difference between leader cell function in these distinct environments was their cell surface expression of the latent TGFβ activator, αvβ3 integrin. This receptor is exclusively found on this CD44+ cell population when they localize to the leading edge of the rigid wound environment. Providing exogenous TGFβ to bypass any differences in the ability of the leader cells to sustain activation of TGFβ in different environments revealed their inherent ability to induce pro-fibrotic reactions on the basement membrane wound environment. Furthermore, exposure of the leader cells in the rigid wound environment to TGFβ led to an accelerated fibrotic response including the earlier appearance of pro-collagen + cells, alpha smooth muscle actin (αSMA)+ myofibroblasts, and increased fibrotic matrix production. Collectively, these findings show the influence of the local wound environment on the extent and severity of TGFβ-induced fibrotic responses. These findings have important implications for understanding the development of the lens fibrotic disease PCO in response to cataract surgery wounding.
•Endogenous TGFβ signals a leader cell fibrotic response in the rigid wound milieu.•TGFβ is dispensable for the wound healing response to cataract surgery injury.•Exogenous TGFβ induced a fibrotic response by leader cells on the lens capsule.•In the rigid wound milieu, exogenous TGFβ led to an augmented fibrotic response.•The local wound milieu regulates the extent of the TGFβ-mediated fibrotic response.
We discuss a portable edge illumination x-ray phase contrast imaging system based on compact piezoelectric motors, which enables its transportation to different environments, e.g., hosting different ...x-ray source technologies. The analysis of images of standard samples reveals an angular sensitivity of 270 ± 6 nrad, which compares well with the 260 ± 10 nrad reported for previous systems based on stepper motors, demonstrating that system portability can be achieved without affecting phase sensitivity. The results can also be considered a test of the performance of the piezoelectric motors, and as such could be of interest to researchers planning their use in other imaging systems.
The success of neurofeedback training for vestibular rehabilitation depends largely on the type of feedback signal as well as on the specific parameters. Ideal training should be based on the ...individual balance deficits in patients in everyday situations. The present study is therefore aimed at investigating the therapeutic outcome of a new vibrotactile neurofeedback system for the first time in a pilot study.
A total of 36 patients performed daily vibrotactile neurofeedback training (for 10 days) based on a sway analysis on the first day. The reduction of body sway and vertigo symptom scale (VSS) scores were calculated after the training and compared with those of the placebo group.
All five patient groups (characterized by different vestibular disorders) which performed the training with the correct feedback signal showed reduced body sway and VSS score (n=30). This effect was not visible in the placebo group.
Individualized vibrotactile neurofeedback training as presented here with the Vertiguard® system appeared to improve balance during daily activities in all patient groups investigated, but not in controls. Future studies should investigate the efficacy of this new method in a larger sample as well as its long term effects.
Edge illumination X-ray phase contrast imaging techniques are capable of quantitative retrieval of differential phase, absorption and X-ray scattering. We have recently developed a series of ...approaches enabling high-resolution implementations, both using synchrotron radiation and laboratory-based set-ups. Three-dimensional reconstruction of absorption, phase and dark-field can be achieved with a simple rotation of the sample. All these approaches share a common trait which consists in the use of an absorber that shapes the radiation field, in order to make the phase modulations introduced by the sample detectable. This enables a well-defined and high-contrast structuring of the radiation field as well as an accurate modelling of the effects that are related to the simultaneous use of a wide range of energies. Moreover, it can also be adapted for use with detectors featuring large pixel sizes, which could be desirable when a high detection efficiency is important.
Nowadays, specific and reproducible side-separated neurotologic testing of all vestibular receptors is possible. Assessment of saccular function by measuring cervical vestibular-evoked myogenic ...potentials (cVEMP) is well established. Reliable screening tests exist for the isolated assessment of utricular function. These tests can be performed even in less well-equipped surroundings to generate information regarding a possible partial dysfunction of the otolith organs. Apart from assessing the functionality of the semicircular canals by caloric irrigation and the head impulse test, screening for otolith disorders should be part of a comprehensive modern vestibular examination. Neurofeedbacktraining is an effective therapy in the treatment of otholith disorders.
The conservative therapy of long-lasting vestibular disorders has been changed over the last few years by the introduction of neuro(bio-)feedback procedures. A technical neurofeedback system applies ...an additional (acoustic, galvanic, vibrotactile) stimulus to the patient while performing vestibular exercises. This stimulus is dependent on the extent of postural deviation of the patient from a normal (ideal) position in space. The neurofeedback system is body worn and continuously registers any postural deviation from the normal position so that it can apply suitable stimuli to the patient. This new way of rehabilitating patients with vertigo seems to be a promising addition in the therapy of long-lasting, complex vestibular disorders as recent studies have demonstrated.
Vestibular evoked myogenic potentials (VEMPs) can be recorded from sternocleidomastoid muscle (SCM) in clinical practice. The aim of the present study was to investigate VEMPs upon direct electrical ...stimulation of the human inferior vestibular nerve to evidence the vestibulocollic reflex arch and their saccular origin, respectively.
Seven subjects were stimulated at the inferior (IVN) and superior (SVN) vestibular nerve. The EMG signals of the SCM were recorded. These recordings were compared to air- and bone-conduction evoked VEMPs with respect to latency and shape.
All subjects showed normal VEMPs upon acoustic stimulation with a latency of 12.8
±
1.4
ms for P13, and 22.7
±
2.0
ms for the N23 pre-operatively. Upon direct electrical stimulation of the IVN, the mean latency of the positive peak was 9.1
±
2.2 and 13.2
±
2.3
ms for the negative one. No contralateral SCM response was found. Electrical stimulation of the SVN did not result in any EMG response of the SCM.
The study shows experimental evidence of the vestibulocollic reflex by direct electrical stimulation of the human IVN for the first time. The method can be utilized to map VIIIth nerve subdivisions and to intraoperatively monitor IVN integrity in a real-time mode.
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