Cécile Parietti-Winkler

Visual sensorial preference delays balance control compensation after vestibular schwannoma surgery

Background: Balance control performance after vestibular schwannoma surgical removal follows a course that is characterised by a deterioration in postural performance immediately after unilateral vestibular deafferentation (uVD) and a recovery process (vestibular compensation). However, sensory strategies for balance vary during tumoral growth, which could lead to differences in the preferential use of sensory afferences. This longitudinal study aimed to assess the post-operative sensorimotor strategies of postural regulation according to sensory preference of balance control before surgery. Methods: Twenty-two patients with vestibular schwannoma (11 relying less on vision (G1), 11 relying more on vision (G2), to control balance before surgery), underwent vestibular, subjective visual vertical (SVV), static posturography and sensory organisation (SOT) tests, before and 8 days, 1 and 3 months after surgery. Results: In G1 patients, little static posturographic and SOT performance deterioration after uVD was observed, despite vestibular test and SVV modifications. In G2 patients, uVD-related modifications followed a time-course characterised by a degradation in posturographic and SOT, vestibular and SVV performances immediately after uVD and a progressive restoration and even improvement 1 month and particularly 3 months after surgery. Conclusions: High preference for vision before surgery intervenes in postural degradation immediately after surgery, thus delaying the short-term effects of vestibular compensation on postural control. Long-term performance being similar whatever the visual status before surgery, the time-dependent implementation of the central adaptive mechanisms due to neuroplasticity leads to a modification of neurosensory information hierarchy, allowing reliance on appropriate information, the gain varying according to the postural task to be performed.

Pre-operative vestibular pattern and balance compensation after vestibular schwannoma surgery.

This longitudinal study aimed to assess the sensorimotor balance strategies before and after vestibular schwannoma (VS) surgery according to the degree of pre-operative vestibular lesion. Thirty-eight VS patients were split in three groups according to caloric vestibular test results before surgery; nine had a symmetrical vestibular response (vestibular normoreflexy), 19 with a decreased response of more than 20% of the affected side (vestibular hyporeflexy) and 10 with an absent caloric response on the side of the affected labyrinth (vestibular areflexy). They underwent pendular rotary vestibular testing (RVT), allowing to evaluate gain and directional preponderance of the vestibulo-ocular reflex, and a sensory organisation test (SOT), evaluating balance control in six conditions (C1 to C6). These tests were performed shortly before, and 8 and 90 days after surgery. Directional preponderance performances of patients with vestibular normoreflexy or hyporeflexy followed a classical time-course with a huge asymmetry just after surgery and a recovery to pre-operative performances at 90 days; patients with vestibular areflexy were relatively stable in time. Variation in SOT performances of patients with vestibular normoreflexy, especially in the more complex C4 to C6, followed a classical time-course with an important postural degradation just after surgery and a recovery to pre-operative performances at 90 days. Patients with vestibular areflexy showed no balance degradation just after surgery and a marked increase in performances at 90 days after surgery, especially in C5 and C6. Performances of patients with vestibular hyporeflexy were intermediate, close to performances of patients with vestibular normoreflexy before surgery and close to performances of patients with vestibular areflexy at 8 and 90 days after surgery. Pre-operative vestibular function alteration triggers an adaptive process, characterized by a restoration of the symmetry of the vestibular nuclei activity and by sensory substitution and new behavioural strategies, allowing the anticipation of unilateral vestibular deafferentation effects.

Impact of pre-operative regular physical activity on balance control compensation after vestibular schwannoma surgery

Vestibular compensation after unilateral vestibular deafferentation is modulated by certain individual characteristics, such as pre-operative visual neurosensory preference or vestibular pattern. Physical activity (PA) allows the implementation of new sensorimotor and behavioral strategies leading to an improvement of balance control. This study aimed to evaluate the effect of the level of PA before surgery on balance compensatory mechanisms in patients after vestibular schwannoma (VS) surgery. Thirty patients with VS, 15 considered as regularly physically active and 15 as sedentary participated in this study, including an evaluation of gaze control by videonystagmography and postural control by a sensory organization test. Patients considered as physically active before surgery presented the best pattern of postural compensation, with the classical decrease in postural performances at short term (i.e. eight days) and the increase in postural performances at middle and long terms (i.e. 90 and 180 days, respectively) after surgery. For the sedentary patients, the consequences of surgery were more difficult to manage at short term, even though this did not prevent the ability to compensate well later on. Pre-operative practice of PA promotes the neuroplasticity of neural networks involved in motor learning, which allows to benefit of physical therapy more rapidly and efficiently.

Otitis media with effusion as a marker of the inflammatory process associated to nasal polyposis

Despite the close location of polyps with the Eustachian tube, association between nasal polyposis (NP) and otitis media with effusion (OME) has not been described in the literature. Our retrospective case-control study aimed at assessing the relative risk to develop OME when NP is associated to factors such as asthma, aspirin intolerance (AI), atopy, eosinophil infiltration of polyp tissue, and history of surgical treatment (HST). We compared the charts of 25 NP patients presenting symptomatic OME with 50 NP patients without OME. All the charts contained validated data about OME, asthma, AI, atopy, eosinophil count in polyp tissue, and HST. Our study showed that the risk to develop OME in NP patients is five times higher in patients presenting aspirin triad (NP + asthma + AI) (OR = 5.6, p = 0.009) and three times higher in HST patients (OR = 3.5, p = 0.03), than in isolated NP patients. A linear trend exists between the different degrees of respiratory disease and the risk of OME (p = 0.01). Our data suggest that the development of OME could be considered as another marker of severity of the inflammatory disease leading to NP, asthma and AI. Better characterisation of NP patients with OME could allow is to define more accurately the nature, type and severity of the underlying inflammatory process.

Is There an Association Between Otitis Media and Nasal Polyposis

The association between otitis media with effusion (OME) and nasal polyposis (NP) is poorly described. However, two different approaches to this problem seem to come from the few studies concerning both otitis media and NP in the literature. One study was based on the assessment of a population of patients presenting with NP, with the authors interested in patients among the studied population who complained of ear-related symptoms and developed OME (rhinologic approach). Other studies were based on the assessment of a population of patients developing a particular OME, with the authors interested in characterizing this condition they named eosinophilic otitis media (otologic approach). The article reviews currents concepts in the relationship between OME and NP. It appears that regardless of the approach to the problem of interest (rhinologic or otologic approach), OME and NP seem to be closely related. Moreover, some striking similarities can be noted between the different entities described in the different studies reviewed, and all authors seem to agree that the middle ear has a central role in the concept of united airways inflammatory disease. Otologists and rhinologists should work together on a single approach that allows for better management of inflammatory disease leading to the formation of polyps, development of concurrent asthma, appearance of aspirin intolerance, and finally involvement of the middle ear.

Cognitive Abilities and Quality of Life After Cochlear Implantation in the Elderly

OBJECTIVE To evaluate quality of life (QoL) and cognitive function in elderly patients with cochlear implants relative to auditory improvement, using geriatric validated scales. STUDY DESIGN Prospective observational study. SETTING A tertiary referral center for cochlear implantation (CI) and a geriatric center in Nancy, France. PATIENTS Sixteen consecutive patients were included, from 65 to 80 years old, with postlingual severe-to-profound deafness. MAIN OUTCOME MEASURES Evaluations were conducted before and at 6 and 12 months after cochlear implant surgery. A monosyllabic word recognition test was used to measure speech perception. QoL was evaluated by the World Health Organization Quality of Life Assessment for elderly people; cognitive function was evaluated by the Mini-Mental State Examination; depression was evaluated by the Hamilton Scale; autonomy was evaluated by the Instrumental Activities of Daily Living. RESULTS Speech intelligibility evolved from 10% before surgery to 63% and 69% at 6 and 12 months after cochlear implant activation, respectively. QoL showed significant improvement in sensory abilities. The Mini-Mental State Examination evaluations remained stable and executive functions tended to improve. Autonomy improved significantly. CONCLUSION Cochlear implantation improves autonomy and the QoL in the elderly. Cognitive functions are not influenced by surgery, but executive functions appear to benefit from implantation. Age should not be a limiting factor, and cochlear implantation can be proposed as an efficient treatment for severe-to-profound hearing loss in the elderly.

Influence of Age on Postural Compensation After Unilateral Deafferentation Due to Vestibular Schwannoma Surgery

To evaluate the age‐related effects of vestibular schwannoma (VS) on postural control and whether the postoperative postural strategies differ according to age.

One-day measurement to assess the auditory risks encountered by noise-exposed workers

Abstract Noise is one of the most pervasive hazards in the workplace. Despite regulations and preventive measures, noise-induced hearing loss is common. The current reference test is pure-tone air-conduction audiometry (PTA), but this test cannot be used to detect early hearing loss. Objective: In this study, we assess one-day auditory fatigue using both PTA and efferent reflexes (ER) measured using DPOAEs associated with contralateral acoustic stimulation (CAS DPOAEs). Design: The noise exposure history, PTA, and ER detection were performed in seven different companies where the LEX,8h was 85 dB(A). Hearing was tested before and at the end of the working day. Study sample: Forty-six volunteers were selected to carry out this study. Results: After a single working day, a greater impact of noise was measured using ER thresholds than PTA or DPOAEs. ER measurements are objective, easy to perform, and do not require a sound-attenuated booth. Conclusion: Screening workers by periodically measuring ER thresholds using CAS DPOAEs helps detect early changes in hearing status, before the onset of noise-induced hearing loss. These tests can be readily applied as part of a hearing conservation program.

Toluene-induced hearing loss in the guinea pig.

Toluene is a high-production industrial solvent, which can disrupt the auditory system in rats. However, toluene-induced hearing loss is species dependent. For instance, despite long-lasting exposures to high concentrations of aromatic solvent, no study has yet succeeded in causing convincing hearing loss in the guinea pig. This latter species can be characterized by two metabolic particularities: a high amount of hepatic cytochrome P-450s (P-450s) and a high concentration of glutathione in the cochlea. It is therefore likely that the efficiency of both the hepatic and cochlear metabolisms plays a key role in the innocuousness of the hearing of guinea pigs to exposure to solvent. The present study was carried out to test the auditory resistance to toluene in glutathione-depleted guinea pigs whose the P-450 activity was partly inhibited. To this end, animals on a low-protein diet received a general P-450 inhibitor, namely SKF525-A. Meanwhile, they were exposed to 1750 ppm toluene for 4 weeks, 5 days/week, 6 h/day. Auditory function was tested by electrocochleography and completed by histological analyses. For the first time, a significant toluene-induced hearing loss was provoked in the P-450-inhibited guinea pigs. However, the ototoxic process caused by the solvent exposure was different from that observed in the rat. Only the stria vascularis and the spiral fibers were disrupted in the apical coil of the cochlea. The protective mechanisms developed by guinea pigs are discussed in the present publication.

Membrane fluidity does not explain how solvents act on the middle-ear reflex

Some volatile aromatic solvents have similar or opposite effects to anesthetics in the central nervous system. Like for anesthetics, the mechanisms of action involved are currently the subject of debate. This paper presents an in vivo study to determine whether direct binding or effects on membrane fluidity best explain how solvents counterbalance anesthesias depression of the middle-ear reflex (MER). Rats were anesthetized with a mixture of ketamine and xylazine while also exposed to solvent vapors (toluene, ethylbenzene, or one of the three xylene isomers) and the amplitude of their MER was monitored. The depth of anesthesia was standardized based on the magnitude of the contraction of the muscles involved in the MER, determined by measuring cubic distortion product oto-acoustic emissions (DPOAEs) while triggering the bilateral reflex with contralateral acoustic stimulation. The effects of the aromatic solvents were quantified based on variations in the amplitude of the DPOAEs. The amplitude of the alteration to the MER measured in anesthetized rats did not correlate with solvent lipophilocity (as indicated by logKow values). Results obtained with the three xylene isomers indicated that the positions of two methyl groups around the benzene ring played a determinant role in solvent/neuronal cell interaction. Additionally, Solid-state Nuclear Magnetic Resonance (NMR) spectra for brain microsomes confirmed that brain lipid fluidity was unaffected by solvent exposure, even after three days (6h/day) at an extremely high concentration (3000ppm). Therefore, aromatic solvents appear to act directly on the neuroreceptors involved in the acoustic reflex circuit, rather than on membrane fluidity. The affinity of this interaction is determined by stereospecific parameters rather than lipophilocity.