Lower Four Cranial Nerves in the Management of Glomus Jugulare: Anatomical Study

Abstract Introduction The surgical management that achieves minimal morbidity and mortality for patients with glomus and non-glomus tumors involving the jugular foramen (JF) region requires a comprehensive understanding of the complex anatomy, anatomic variability, and pathological anatomy of this region. Objective The aim of this study is to propose a rational guideline to expose and preserve the lower cranial nerves (CNs) in the lateral approach of the JF. Methods The technique utilized is the gross and microdissection of 4 fixed cadaveric heads to revise the JF's surgical anatomy and high part of the carotid sheath compared with surgical cases to understand and preserve the integrity of lower CNs. The method involves radical mastoidectomy, microdissection of the JF, facial nerve, and high neck just below the carotid canal and the JF. The CNs IX, X, XI, and XII are microscopically dissected and kept in sight up to the JF. Results This study realized well the surgical and applied anatomy of the lower CNs with relation to the facial nerve and JF. Conclusions The JF anatomy is complicated, and the key to safely operate on it and preserving the lower CNs is to find the posterior belly of the digastric muscle, to skeletonize the facial nerve, to remove the mastoid tip preserving the stylomastoid foramen, to skeletonize the sigmoid sinus and posterior fossa dura not only anterior but also posteroinferior to reach and drill the jugular tubercle.

Lower Four Cranial Nerves in the Management of Glomus Jugulare: Anatomical Study.

Introduction The surgical management that achieves minimal morbidity and mortality for patients with glomus and non-glomus tumors involving the jugular foramen (JF) region requires a comprehensive understanding of the complex anatomy, anatomic variability, and pathological anatomy of this region. Objective The aim of this study is to propose a rational guideline to expose and preserve the lower cranial nerves (CNs) in the lateral approach of the JF. Methods The technique utilized is the gross and microdissection of 4 fixed cadaveric heads to revise the JF's surgical anatomy and high part of the carotid sheath compared with surgical cases to understand and preserve the integrity of lower CNs. The method involves radical mastoidectomy, microdissection of the JF, facial nerve, and high neck just below the carotid canal and the JF. The CNs IX, X, XI, and XII are microscopically dissected and kept in sight up to the JF. Results This study realized well the surgical and applied anatomy of the lower CNs with relation to the facial nerve and JF. Conclusions The JF anatomy is complicated, and the key to safely operate on it and preserving the lower CNs is to find the posterior belly of the digastric muscle, to skeletonize the facial nerve, to remove the mastoid tip preserving the stylomastoid foramen, to skeletonize the sigmoid sinus and posterior fossa dura not only anterior but also posteroinferior to reach and drill the jugular tubercle.

Efficacy and Safety of Intranasal Betahistine in the Treatment of Surgery-Induced Acute Vestibular Syndrome: A Double-Blind, Randomized, Placebo-Controlled Phase 2 Study.

OBJECTIVE: To evaluate the safety and efficacy of AM-125 nasal spray (intranasal betahistine) in the treatment of surgery-induced acute vestibular syndrome (AVS). STUDY DESIGN: Prospective, double-blind, randomized, placebo-controlled exploratory phase 2 study with dose escalation (part A) followed by parallel dose testing (part B); open-label oral treatment for reference. SETTING: Twelve European study sites (tertiary referral centers). PATIENTS: One hundred and twenty-four patients 18 to 70 years old undergoing surgery for vestibular schwannoma resection, labyrinthectomy or vestibular neurectomy with confirmed bilateral vestibular function presurgery and acute peripheral vertigo postsurgery. INTERVENTIONS: AM-125 (1, 10, or 20 mg) or placebo or betahistine 16 mg p.o. t.i.d. for 4 weeks, starting 3 days postsurgery; standardized vestibular rehabilitation. MAIN OUTCOME MEASURES: Tandem Romberg test (TRT) for primary efficacy, standing on foam, tandem gait, subjective visual vertical and spontaneous nystagmus for secondary efficacy, Vestibular Rehabilitation Benefit Questionnaire (VRBQ) for exploratory efficacy; nasal symptoms and adverse events for safety. RESULTS: At treatment period end, mean TRT improvement was 10.9 seconds for the 20-mg group versus 7.4 seconds for the placebo group (mixed model repeated measures, 90% confidence interval = 0.2 to 6.7 s; p = 0.08). This was corroborated by nominally higher frequency of complete spontaneous nystagmus resolution (34.5% vs. 20.0% of patients) and improvement in the VRBQ; the other secondary endpoints showed no treatment effect. The study drug was well tolerated and safe. CONCLUSIONS: Intranasal betahistine may help accelerate vestibular compensation and alleviate signs and symptoms of vestibular dysfunction in surgery-induced AVS. Further evaluation in a confirmatory manner appears warranted.

Exploring the middle ear function in patients with a cluster of symptoms including tinnitus, hyperacusis, ear fullness and/or pain.

Middle ear muscle (MEM) abnormalities have been proposed to be involved in the development of ear-related symptoms such as tinnitus, hyperacusis, ear fullness, dizziness and/or otalgia. This cluster of symptoms have been called the Tonic Tensor Tympani Syndrome (TTTS) because of the supposed involvement of the tensor tympani muscle (TTM). However, the putative link between MEM dysfunction and the symptoms has not been proven yet and the detailed mechanisms (the causal chain) of TTTS are still elusive. It has been speculated that sudden loud sound (acoustic shock) may impair the functioning of the MEM, specifically the TTM, after an excessive contraction. This would result in inflammatory processes, activation of the trigeminal nerve and a change of the MEMs state into a hypersensitive one, that may be associated to the cluster of symptoms listed above. The goal of this study is to provide further insights into the mechanisms of TTTS. The middle ear function of 11 patients who reported TTTS symptoms has been investigated using either admittancemetry and/or measurement of air pressure in the sealed external auditory canal. While the former method measured the middle ear stiffness the latter provides an estimate of the tympanic membrane displacement. Most patients displayed results consistent with phasic contractions of the TTM (n = 9) and/or Eustachian Tube (ET) dysfunction (n = 6). The MEM contraction or ET dysfunction could be evoked by acoustic stimulation (n = 3), somatic maneuvers (n = 3), or pressure changes in the ear canal (n = 3). Spontaneous TTM contraction (n = 1) or ET opening (n = 1) could also be observed. Finally, voluntary contraction of MEM was also reported (n = 5). On the other hand, tonic contraction of the TTM could not be observed in any patient. The implications of these results for the mechanisms of TTTS are discussed.

Contraction of the stapedius and tensor tympani muscles explored by tympanometry and pressure measurement in the external auditory canal.

It has been suggested that tensor tympani muscle (TTM) contraction may be involved in the development of ear-related pathologies such as tinnitus, hyperacusis and otalgia, called the tonic tensor tympani syndrome (TTTS). However, as there is no precise measure of TTM function under normal and pathological states, its involvement remains speculative. When the TTM or the stapedius muscle (SM) contracts, they both generate an increase of middle ear stiffness that can be measured through middle ear admittance. However, this technique cannot differentiate the contraction between the two muscles. On the other hand, the air pressure measured in a sealed external auditory canal can provide a measure of the eardrum displacement that may be able to differentiate SM from TTM contraction. TTM is attached to the malleus, and its contraction causes a retraction of the eardrum inside the middle ear cavity, while SM can have a small but reversed effect on TTM displacement. To investigate this issue, we compared the middle ear admittance and air pressure in a sealed external ear canal upon auditory stimulation (sMEMC) and voluntary middle ear muscle contraction (vMEMC). In addition, we assessed the perceptual effect of vMEMC, including pitch and loudness matching of the fluttering noise produced by vMEMC and the threshold shifts, were measured. Out of the 14 ears tested, sMEMC was associated with a decrease of admittance in 93% (mean peak average: -0.06 ml, SD:0.04) and an increase of air pressure in 29% of ears (mean peak average: 8.1 Pa, SD:5.1). No decrease in air pressure was found upon sMEMC. For vMEMC (n = 8 ears), decreases were found for both admittance and air pressure in 100% and 88%, with a mean peak average of -0.38 ml, SD: 0.54 and -149 Pa, SD:156, for admittance and pressure respectively. These results suggest that SM and TTM are involved in sMEMC and vMEMC, respectively. In addition, vMEMC was associated with perceptual effects including a low-frequency sound, pitch-matched at ∼30 Hz (>15 dB SL), and a low-frequency hearing loss of at least 10 dB between 20 and 200 Hz. In conclusion, admittance and air pressure recordings provide useful and complementary information on middle ear muscle contraction and can be used to explore the middle ear function.

Analysis of the Acoustic Transcranial Bone Conduction.

OBJECTIVES: (1) To analyze the preferential pathways of sound transmission and sound waves travelling properties in the skull and (2) to identify the location(s) on the skull where bone conduction to the cochlea is optimal. STUDY DESIGN: Basic research Methods: Nine cadaveric heads were placed in an anechoic chamber and equipped with six Bone Anchored Hearing Aids (BAHA™) implants (Cochlear™, Sydney, NSW, Australia) and fifteen accelerometers. A laser velocimeter was used to measure cochlear response by placing a reflector on the round window. Different frequency sweeps were applied to each implant, and measurements were recorded simultaneously by the laser velocimeter and accelerometers. RESULTS: Low-frequency sound waves mostly travel the frontal transmission pathways, and there is no clear predominant pattern for the high frequencies. The mean inter-aural time lag is 0.1 ms. Optimal sound transmission to the cochlea occurs between 1000 and 2500 Hz with a contralateral 5 to 10 dB attenuation. The implant location does not influence mean transmission to the cochlea. CONCLUSION: There is a pattern of transmission for low frequencies through a frontal pathway but none for high frequencies. We were also able to demonstrate that the localization of the BAHA™ implant on the skull had no significant impact on the sound transmission, either ipsi or contralaterally.

Ultrarare heterozygous pathogenic variants of genes causing dominant forms of early-onset deafness underlie severe presbycusis.

Presbycusis, or age-related hearing loss (ARHL), is a major public health issue. About half the phenotypic variance has been attributed to genetic factors. Here, we assessed the contribution to presbycusis of ultrarare pathogenic variants, considered indicative of Mendelian forms. We focused on severe presbycusis without environmental or comorbidity risk factors and studied multiplex family age-related hearing loss (mARHL) and simplex/sporadic age-related hearing loss (sARHL) cases and controls with normal hearing by whole-exome sequencing. Ultrarare variants (allele frequency [AF] < 0.0001) of 35 genes responsible for autosomal dominant early-onset forms of deafness, predicted to be pathogenic, were detected in 25.7% of mARHL and 22.7% of sARHL cases vs. 7.5% of controls (P = 0.001); half were previously unknown (AF < 0.000002). MYO6, MYO7A, PTPRQ, and TECTA variants were present in 8.9% of ARHL cases but less than 1% of controls. Evidence for a causal role of variants in presbycusis was provided by pathogenicity prediction programs, documented haploinsufficiency, three-dimensional structure/function analyses, cell biology experiments, and reported early effects. We also established Tmc1N321I/+ mice, carrying the TMC1:p.(Asn327Ile) variant detected in an mARHL case, as a mouse model for a monogenic form of presbycusis. Deafness gene variants can thus result in a continuum of auditory phenotypes. Our findings demonstrate that the genetics of presbycusis is shaped by not only well-studied polygenic risk factors of small effect size revealed by common variants but also, ultrarare variants likely resulting in monogenic forms, thereby paving the way for treatment with emerging inner ear gene therapy.

Unilateral vestibular deafferentation impairs embodied spatial cognition.

A growing number of studies indicate that cognitive complaints are common in patients with peripheral vestibular disorders. A better understanding of how vestibular disorders influence cognition in these patients requires a clear delineation of the cognitive domains affected by vestibular disorders. Here, we compared the consequences of left and right vestibular neurectomy on third-person perspective taking-a visuo-spatial task requiring mainly own-body mental imagery, and on 3D objects mental rotation imagery-requiring object-based mental imagery, but no perspective taking. Patients tested 1 week after a unilateral vestibular neurectomy and a group of age- and gender-matched healthy participants played a virtual ball-tossing game from their own first-person perspective (1PP) and from the perspective of a distant avatar (third-person perspective, 3PP). Results showed larger response times in the patients with respect to their controls for the 3PP taking task, but not for the 1PP task and the 3D objects mental imagery. In addition, we found that only patients with left vestibular neurectomy presented altered 3PP taking abilities when compared to their controls. This study suggests that unilateral vestibular loss affects mainly own-body mental transformation and that only left vestibular loss seems to impair this cognitive process. Our study also brings further evidence that vestibular signals contribute to the sensorimotor bases of social cognition and strengthens the connections between the so far distinct fields of social neuroscience and human vestibular physiology.

Transcutaneous Baha Attract system: Long-term outcomes of the French multicenter study.

BACKGROUND: Bone conduction implants based on abutment-driven acoustic transmission result in good hearing outcomes; however, skin complications impact the quality of life (QOL) and possibly the viability of the device for many patients. The transcutaneous magnetic Baha® Attract technology was developed with the goal of minimising skin complications. OBJECTIVES: To analyse surgical, auditory and QOL outcomes for patients implanted with the Baha® Attract. DESIGN: Prospective multicentre cohort study. SETTING: Four French tertiary referral centres. PARTICIPANTS: Thirty-two patients implanted with the Baha® Attract, including 25 with conductive and mixed hearing loss and 7 with single-sided deafness. MAIN OUTCOME MEASURES: Postoperative follow-up involved the visual analysis of soft tissue adaptation and sound processor magnet strength measurement. The audiometric outcomes were evaluated in quiet and noise, and the QOL was assessed using three different questionnaires. RESULTS: After 12 months of use, soft tissue was thinner, and mean magnet strength was significantly decreased (3.7-3.1, P < 0.05) relative to measures during surgery. The speech recognition threshold in quiet significantly improved compared to unaided situation (73-44 dB HL respectively, P < 0.001) as did functional gain in noise (+2.8). All QOL scores improved, and the APHAB questionnaire score correlated with the audiometric outcomes. CONCLUSIONS: The Baha® Attract technology results in significant hearing gain and improves QOL. Skin complications were not observed, although surgeons, audiologists and patients should be aware of soft tissue evolution during the first postoperative year. The reversibility of this implant is a major advantage that allows switching to another system if hearing degrades.

Diagnosis and Treatment of Perilymphatic Fistula.

Perilymphatic fistula (PLF) is defined as an abnormal communication between the fluid (perilymph)-filled space of the inner ear and the air-filled space of the middle ear and mastoid, or cranial spaces. PLF is located in the round or oval window, fractured bony labyrinth, microfissures, anomalous footplate, and can occur after head trauma or barotrauma, chronic inflammation, or in otic capsule dehiscence. This clinical entity was initially proposed more than a century ago, yet it has remained a topic of controversy for more than 50 years. The difficulty of making a definitive diagnosis of PLF has caused a long-standing debate regarding its prevalence, natural history, management and even its very existence. In this present study, we will discuss the symptoms, physiological tests (focusing on vestibular assessment) and imaging studies. Referring to a previous criticism, we will share our classification of PLF into 4 categories. Furthermore, we will summarize a nationwide survey using a novel and widely used biomarker (Cochlin-tomoprotein [CTP]) for PLF diagnosis in Japan and present the results of the new diagnostic criteria. PLF is surgically correctable by sealing the fistula, and appropriate recognition and treatment of PLF can improve hearing and balance, and in turn, improve the quality of life of afflicted patients. Therefore, PLF is an especially important treatable disease for otologists.

Isolation and characterization of olfactory ecto-mesenchymal stem cells from eight mammalian genera.

BACKGROUND: Stem cell-based therapies are an attractive option to promote regeneration and repair defective tissues and organs. Thanks to their multipotency, high proliferation rate and the lack of major ethical limitations, "olfactory ecto-mesenchymal stem cells" (OE-MSCs) have been described as a promising candidate to treat a variety of damaged tissues. Easily accessible in the nasal cavity of most mammals, these cells are highly suitable for autologous cell-based therapies and do not face issues associated with other stem cells. However, their clinical use in humans and animals is limited due to a lack of preclinical studies on autologous transplantation and because no well-established methods currently exist to cultivate these cells. Here we evaluated the feasibility of collecting, purifying and amplifying OE-MSCs from different mammalian genera with the goal of promoting their interest in veterinary regenerative medicine. Biopsies of olfactory mucosa from eight mammalian genera (mouse, rat, rabbit, sheep, dog, horse, gray mouse lemur and macaque) were collected, using techniques derived from those previously used in humans and rats. The possibility of amplifying these cells and their stemness features and differentiation capability were then evaluated. RESULTS: Biopsies were successfully performed on olfactory mucosa without requiring the sacrifice of the donor animal, except mice. Cell populations were rapidly generated from olfactory mucosa explants. These cells displayed similar key features of their human counterparts: a fibroblastic morphology, a robust expression of nestin, an ability to form spheres and similar expression of surface markers (CD44, CD73). Moreover, most of them also exhibited high proliferation rates and clonogenicity with genus-specific properties. Finally, OE-MSCs also showed the ability to differentiate into mesodermal lineages. CONCLUSIONS: This article describes for the first time how millions of OE-MSCs can be quickly and easily obtained from different mammalian genera through protocols that are well-suited for autologous transplantations. Moreover, their multipotency makes them relevant to evaluate therapeutic application in a wide variety of tissue injury models. This study paves the way for the development of new fundamental and clinical studies based on OE-MSCs transplantation and suggests their interest in veterinary medicine.

From Blood to Lesioned Brain: An In Vitro Study on Migration Mechanisms of Human Nasal Olfactory Stem Cells.

Stem cell-based therapies critically rely on selective cell migration toward pathological or injured areas. We previously demonstrated that human olfactory ectomesenchymal stem cells (OE-MSCs), derived from an adult olfactory lamina propria, migrate specifically toward an injured mouse hippocampus after transplantation in the cerebrospinal fluid and promote functional recoveries. However, the mechanisms controlling their recruitment and homing remain elusive. Using an in vitro model of blood-brain barrier (BBB) and secretome analysis, we observed that OE-MSCs produce numerous proteins allowing them to cross the endothelial wall. Then, pan-genomic DNA microarrays identified signaling molecules that lesioned mouse hippocampus overexpressed. Among the most upregulated cytokines, both recombinant SPP1/osteopontin and CCL2/MCP-1 stimulate OE-MSC migration whereas only CCL2 exerts a chemotactic effect. Additionally, OE-MSCs express SPP1 receptors but not the CCL2 cognate receptor, suggesting a CCR2-independent pathway through other CCR receptors. These results confirm that OE-MSCs can be attracted by chemotactic cytokines overexpressed in inflamed areas and demonstrate that CCL2 is an important factor that could promote OE-MSC engraftment, suggesting improvement for future clinical trials.

How minimally invasive vestibular neurotomy for incapacitating Meniere's disease improves dizziness and anxiety.

CONCLUSION: Patients with incapacitating Meniere Disease (MD) suffer in their daily lives and activities because of the dizziness and anxiety induced by MD. Minimally Invasive Vestibular Neurotomy (MIVN) is a safe and effective surgical treatment for these individuals, and improved their dizziness and anxiety. OBJECTIVES: This study aimed to assess the state of dizziness and anxiety of patients with incapacitating MD and its improvement through MIVN. METHOD: A total of 118 patients with incapacitating MD who underwent MIVN in France and Japan were evaluated. The DHI (Dizziness Handicap Inventory), SAST (Short Anxiety Screening Test), and STAI (State Trait Anxiety Index) questionnaires were used to evaluate disequilibrium and anxiety. RESULTS: The MIVN method appears safe and effective for patients with incapacitating MD. Pre-operative assessment results by DHI and SAST were significantly related to each other, and were influenced by lifestyle and profession. This prospective study showed that MIVN improved dizziness and anxiety in these patients.

A Retrospective Multicentre Cohort Review of Patient Characteristics and Surgical Aspects versus the Long-Term Outcomes for Recipients of a Fully Implantable Active Middle Ear Implant.

OBJECTIVE: To summarise treatment outcomes compared to surgical and patient variables for a multicentre recipient cohort using a fully implantable active middle ear implant for hearing impairment. To describe the authors' preferred surgical technique to determine microphone placement. STUDY DESIGN: Multicentre retrospective, observational survey. SETTING: Five tertiary referral centres. PATIENTS: Carina recipients (66 ears, 62 subjects) using the current Cochlear® Carina® System or the legacy device, the Otologics® Fully Implantable Middle Ear, with a T2 transducer. METHODS: Patient file review and routine clinical review. Patient outcomes assessed were satisfaction, daily use and feedback reports at the first fitting and ≥12 months after implantation. Descriptive and statistical analysis of correlations of variables and their influence on outcomes was performed. Independently reported preferred methods for microphone placement are collectively summarised. RESULTS: The average implant experience was 3.5 years. Satisfaction increased significantly over time (p < 0.05). No correlation with covariates examined was observed. Feedback significantly decreased over time, showing a significant correlation with microphone location, primary motivation, gender, age at implantation, and contralateral hearing aid use (p < 0.05). Patient satisfaction was inversely correlated with reports of system feedback (p < 0.05). The implantable microphone was most commonly on the posterior inferior mastoid line, in 42/66 (65%) cases, correlating with less likelihood for feedback and consistent with author surgical preference. CONCLUSION: Carina recipients in this study present as satisfied consistent daily users with very few reports of persistent feedback. As microphone location is an influencing factor, a careful surgical consideration of microphone placement is required. The authors prefer a posterior inferior mastoid line position whenever possible.

Changing perspective: The role of vestibular signals.

Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others' actions.

Intralabyrinthine Penetrating Ventilation Tube with Preservation of Hearing: An Unusual Clinical Situation

Introduction Traumatic perilymphatic fistula is not a rare event with regards to sport activities or traffic accident. However, iatrogenic damage to the inner ear can occur following the common use of grommets and ventilation tube insertion. Objectives To report an unusual case of insertion of aeration tube into the vestibule trough the stapes footplate. Resumed Report A 62-year-old woman experienced iatrogenic penetration into the vestibule from a ventilation tube inserted for retraction pocket management. The event was misdiagnosed both by the surgeon and by the emergency room physicians, leading to delay in the management. However, preservation of the hearing function lasted for 2 weeks prior to deafness, thanks to the valve of Bast, which preserved the cochlear fluid. Conclusion This case gives us the opportunity to stress the need for systematic clinical examination of traumatic injury to the ear and to recommend performing multiplanar millimetric computed tomography scan with accurate interpretation. Traumatic injuries should be referred to a dedicated traumatic emergency referral center. .

Intralabyrinthine penetrating ventilation tube with preservation of hearing: an unusual clinical situation.

Introduction Traumatic perilymphatic fistula is not a rare event with regards to sport activities or traffic accident. However, iatrogenic damage to the inner ear can occur following the common use of grommets and ventilation tube insertion. Objectives To report an unusual case of insertion of aeration tube into the vestibule trough the stapes footplate. Resumed Report A 62-year-old woman experienced iatrogenic penetration into the vestibule from a ventilation tube inserted for retraction pocket management. The event was misdiagnosed both by the surgeon and by the emergency room physicians, leading to delay in the management. However, preservation of the hearing function lasted for 2 weeks prior to deafness, thanks to the valve of Bast, which preserved the cochlear fluid. Conclusion This case gives us the opportunity to stress the need for systematic clinical examination of traumatic injury to the ear and to recommend performing multiplanar millimetric computed tomography scan with accurate interpretation. Traumatic injuries should be referred to a dedicated traumatic emergency referral center.

Evolution of the reliability of the fully implantable middle ear transducer over successive generations.

OBJECTIVE: To describe the reliability of the fully implantable middle ear transducer after successive technological changes. STUDY DESIGN: Prospective, observational, multicenter study. SETTING: Eight tertiary referral centers. PATIENTS: One hundred twenty-three adults were implanted with one of the five successive versions of the fully implantable middle ear implant between September 2005 and July 2012. METHODS: The reliability of each generation 2 years after implantation or at the maximal lifetime was reported by means of survival curves. Only technological failures were considered; non-technological failures were excluded from the analysis of reliability. RESULTS: One hundred fifty-seven devices were implanted during the period of study. Fifteen explantations were related to non-technological problems (e.g., infections, extrusions, etc.). One hundred forty-two implants were followed in the analysis of reliability. We observed 32 technical failures at 2 years. At the maximal lifetime of follow-up, 46 implants failed. The end of the follow-up was the first of November 2012. Survival rates at 2 years were 0%, 76.1%, 84.2%, 81.8%, and 100% for each of the successive available versions, respectively. CONCLUSION: The reliability of the fully implantable middle ear implant improved over generations thanks to successive technological modifications that corrected the observed failures. The latest generation seems to be a reliable fully implantable middle ear implant system up to 22 months after implantation. The need to know the reliability of these active middle ear implants incites the creation of a follow-up register including patient's data and device failures to improve patient management.

Unilateral vestibular loss impairs external space representation.

The vestibular system is responsible for a wide range of postural and oculomotor functions and maintains an internal, updated representation of the position and movement of the head in space. In this study, we assessed whether unilateral vestibular loss affects external space representation. Patients with Menière's disease and healthy participants were instructed to point to memorized targets in near (peripersonal) and far (extrapersonal) spaces in the absence or presence of a visual background. These individuals were also required to estimate their body pointing direction. Menière's disease patients were tested before unilateral vestibular neurotomy and during the recovery period (one week and one month after the operation), and healthy participants were tested at similar times. Unilateral vestibular loss impaired the representation of both the external space and the body pointing direction: in the dark, the configuration of perceived targets was shifted toward the lesioned side and compressed toward the contralesioned hemifield, with higher pointing error in the near space. Performance varied according to the time elapsed after neurotomy: deficits were stronger during the early stages, while gradual compensation occurred subsequently. These findings provide the first demonstration of the critical role of vestibular signals in the representation of external space and of body pointing direction in the early stages after unilateral vestibular loss.

18F-FDG PET/CT as a predictor of hereditary head and neck paragangliomas.

BACKGROUND: Hereditary head and neck paragangliomas (HNPGLs) account for at least 35% of all HNPGLs, most commonly due to germline mutations in SDHx susceptibility genes. Several studies about sympathetic paragangliomas have shown that (18)F-FDG PET/CT was not only able to detect and localize tumours, but also to characterize tumours ((18)F-FDG uptake being linked to SDHx mutations). However, the data concerning (18)F-FDG uptake specifically in HNPGLs have not been addressed. The aim of this study was to evaluate the relationship between (18)F-FDG uptake and the SDHx mutation status in HNPGL patients. METHODS: (18)F-FDG PET/CT from sixty HNPGL patients were evaluated. For all lesions, we measured the maximum standardized uptake values (SUVmax), and the uptake ratio defined as HNPGL-SUVmax over pulmonary artery trunk SUVmean (SUVratio). Tumour sizes were assessed on radiological studies. RESULTS: Sixty patients (53.3% with SDHx mutations) were evaluated for a total of 106 HNPGLs. HNPGLs-SUVmax and SUVratio were highly dispersed (1.2-30.5 and 1.0-17.0, respectively). The HNPGL (18)F-FDG uptake was significantly higher in SDHx versus sporadic tumours on both univariate and multivariate analysis (P = 0.002). We developed two models for calculating the probability of a germline SDHx mutation. The first one, based on a per-lesion analysis, had an accuracy of 75.5%. The second model, based on a per-patient analysis, had an accuracy of 80.0%. CONCLUSIONS: (18)F-FDG uptake in HNPGL is strongly dependent on patient genotype. Thus, the degree of (18)F-FDG uptake in these tumours can be used clinically to help identify patients in whom SDHx mutations should be suspected.