In all vertebrates, maintaining trunk posture primarily depends on descending commands originating from brainstem vestibulospinal nuclei. Despite being broadly outlined across species, the detailed anatomical and operational structure of these vestibulospinal networks remains poorly understood. Xenopus frogs have previously served as an excellent model for exploring such anatomical and functional aspects in relation to the animal\'s behavioral requirements. In this study, we examined the reflex motor reactions induced by vestibular stimulation in pre-metamorphic tadpoles. Our findings indicate that natural vestibular stimulation in the horizontal plane yields greater efficacy compared to stimulation in other planes, a phenomenon replicated in a frequency-dependent manner through specific galvanic stimulation (GVS) of the horizontal semicircular canals. With the exception of a very rostral cluster of neurons that receive vestibular inputs and project to the spinal cord, the overall anatomical segregation of vestibulospinal nuclei in the brainstem mirrors that observed in juvenile frogs. However, our results suggest closer similarities to mammalian organization than previously acknowledged. Moreover, we demonstrated that vestibulospinal cells project not only to spinal motoneurons in rostral segments but also to more distal segments that undergo regression during metamorphosis. Lastly, we illustrated how vestibular-induced spinal reflexes change during larval development, transitioning from tail swim-based activity to rostral trunk bursting responses, likely anticipating postural control in post-metamorphic frogs.

Self-motion perception is a vital skill for all species. It is an inherently multisensory process that combines inertial (body-based) and relative (with respect to the environment) motion cues. Although extensively studied in human and non-human primates, there is currently no paradigm to test self-motion perception in rodents using both inertial and relative self-motion cues. We developed a novel rodent motion simulator using two synchronized robotic arms to generate inertial, relative, or combined (inertial and relative) cues of self-motion. Eight rats were trained to perform a task of heading discrimination, similar to the popular primate paradigm. Strikingly, the rats relied heavily on airflow for relative self-motion perception, with little contribution from the (limited) optic flow cues provided-performance in the dark was almost as good. Relative self-motion (airflow) was perceived with greater reliability vs. inertial. Disrupting airflow, using a fan or windshield, damaged relative, but not inertial, self-motion perception. However, whiskers were not needed for this function. Lastly, the rats integrated relative and inertial self-motion cues in a reliability-based (Bayesian-like) manner. These results implicate airflow as an important cue for self-motion perception in rats and provide a new domain to investigate the neural bases of self-motion perception and multisensory processing in awake behaving rodents.

OBJECTIVE: To evaluate diagnostic trends in pediatric and adult patients presenting for multidisciplinary subspecialty evaluation of dizziness and imbalance across the lifespan.
METHODS: Retrospective chart review.
METHODS: Single pediatric and single adult academic tertiary care hospital.
METHODS: Retrospective review of electronic health record for patients presenting to an adult or pediatric multidisciplinary vestibular clinic from 2017 to 2020, including clinical data, physical therapy evaluation, and audiovestibular testing.
RESULTS: A total of 1934 patients aged 1 to 95 were evaluated. Most patients were female (n = 1188, 61%); the largest cohort was in the fifth decade of life (n = 321, 17%). Seventy-six percent of patients (n = 1470) were assigned a pathologic diagnosis. Central causes of dizziness were most common in children and young adults, comprising 38% to 54% of all diagnoses in ages 1 to 30. The proportion of peripheral vestibular disorders increased with age, peaking at 32% in ages 61 to 70. Vestibular migraine was the most common pathologic diagnosis in ages 6 to 20 (n = 110, 39%) and 31 and 50 (n = 69, 17%) regardless of gender, but was more prevalent in females (21% vs 14%; P < .0001). The prevalence of benign paroxysmal positional vertigo (BPPV) increased throughout the lifespan, peaking at age 71 to 80. Meniere\'s disease (MD) did not occur within the first decade of life, but increased thereafter, peaking at ages 51 to 60.
CONCLUSIONS: Multidisciplinary vestibular evaluation resulted in a diagnosis for the majority of patients. Vestibular diagnoses vary across the lifespan however among most age groups, central disorders, including migraine disorders, outnumber peripheral vestibulopathies. The prevalence of peripheral vestibular disorders such as BPPV and MD increased with age.
METHODS: Level IV.

This retrospective study describes the surgical outcomes of our first 20 transgender women to undergo feminization thyroid laryngochondroplasty (FLC) by a direct transvestibular FLC (DTV-FLC) approach from December 2019 to October 2023. The medical records of all patients were retrieved and reviewed. Data on the operative, postoperative, and follow-up courses, complications, and functional and cosmetic outcomes were retrieved. The cosmetic results were evaluated by four independent facial plastic surgeons. Thirteen patients underwent DTV-FLC combined with genioplasty or genioplasty with mandibular angle reduction and seven underwent isolated DTV-FLC. DTV-FLC was feasible in all planned cases. Complications (skin flap perforation, thyroid cartilage fracture, mental hypoesthesia, hematoma, dehiscence of the vestibular incision, vestibular scar adhesions, and anemia) were minor and resolved spontaneously. The preoperative grade of thyroid cartilage protrusion was 1.9 ± 0.9 on a scale from 1 to 3. The postoperative cosmetic results of 18 patients were judged as having improved (a score of 2.1 ± 0.8 on a scale from -1 to 3). Eighteen patients were satisfied with the cosmetic result, one was dissatisfied (the revision surgery patient), and one was lost to follow-up. In conclusion, DTV-FTLC is a valid surgical approach for FLC, yielding high patient satisfaction and good cosmetic results.

Galvanic Vestibular Stimulation (GVS) has been proposed as an alternative display modality to relay information without increasing demands on the visual or auditory sensory modalities of the wearer or in environments where those modalities cannot be used (e.g., covert night operations). We further investigated this concept with four experiments designed to test: (1) thresholds at which subjects could distinguish between different GVS current amplitudes and polarities, (2) thresholds at which different bipolar (i.e., sinusoidal waveform with current oscillating between left and right directions) current frequencies were distinguishable among room temperature, hot, cold, and windy environments, (3) effects of unipolar (i.e., sinusoidal waveform with current occurring in only the left or right direction) currents on balance performance, and (4) dual-task performance among frequency and polarity modulated GVS conditions during a concordant visual search task. Subjects reliably distinguished between current amplitudes that varied from a pedestal of ± 0.6 mA by a median of 0.03 mA (range of 0.02-0.32 mA) and between unipolar currents at a median amplitude of 0.55 mA (range of 0.32-0.83 mA). GVS frequency thresholds were robust to the environment conditions tested, with no statistical differences found. Sway and balance errors were increased with unipolar currents. GVS thresholds were not impacted by the dual-task paradigm, but the visual search scores were slightly elevated when congruently performing a polarity thresholding task. Overall findings continue to support GVS use as a display modality, but some limitations are noted, such as the use of unipolar currents under scenarios where postural control is important.

UNASSIGNED: Usher\'s syndrome type II (USH2) is a rare genetic disorder encompassing hearing loss, vision impairment, and apparent intact vestibular function. Recent research suggests a potential involvement of the otolith vestibular receptors in USH2.
UNASSIGNED: Evaluate otolith dynamic function in USH2.
UNASSIGNED: Twenty-two USH2 (median age 53.9 ± 2.99) and age-matched controls underwent a complete battery vestibular testing including air conducted cervical and ocular vestibular evoked myogenic potentials (c-VEMPs and o-VEMPs). Vestibular function tests were correlated with Activities Balance Scale (ABC) and Dizziness Handicap Inventory (DHI) scores.
UNASSIGNED: Fourteen USH2 reported previous vertigo (vs none control). Among 88 ears, c-VEMPs were absent in 15 USH2 cases and 4 controls (p = 0.034), while o-VEMPs were absent in 22 USH2 cases and 12 controls (p = 0.129). There were significant differences between USH2 vs controls in right ear o-VEMP N1 latencies (median 11.60/10.40, p < 0.010), N1-P1 amplitudes (median 5.15/10.10, p < 0.003) and in o-VEMP N1-P1 asymmetry ratio (median 24.78/40.50, p < 0.014). USH2 showed a strong correlation between o-VEMP amplitude and DHI score (p = 0.003, ρ = 0.769). No association was found between vertigo and VEMPs subgroups.
UNASSIGNED: Our findings suggest the presence of otolith dysfunction in USH2, which is independent from subjectively reported dizziness. Incorporating vestibular testing into USH2 evaluation and monitoring could enhance characterization of this multisensory disease.

This single case study describes the audiological and vestibular findings of a female patient, aged 62, with diabetes mellitus and rheumatoid arthritis. Based on this case study, we hypothesize that individuals with diabetes mellitus and rheumatoid arthritis are more vulnerable to vestibular impairment. The current findings indicate that central vestibular lesions and bilateral sensorineural hearing loss are related to rheumatoid arthritis and diabetes. Therefore concluding early detection and follow-up is required to understand pathophysiology in detail.

Audiovestibular dysfunction in patients with systemic lupus erythematosus has been underestimated for decades. Systemic lupus erythematosus can affect both the auditory and vestibular systems simultaneously. Several potential pathophysiological mechanisms behind systemic lupus erythematosus-related audiovestibular dysfunction have been proposed, including antibody-mediated immune responses, cell-mediated cytotoxicity, immune complex deposition in microvessels, central involvement in the audiovestibular pathway, and ototoxicity from medications used in systemic lupus erythematosus treatment. Currently available tests to evaluate audiovestibular function in systemic lupus erythematosus patients are neither specific nor sensitive. Nevertheless, there is no consensus regarding the efficacy of treatments for audiovestibular dysfunction in such patients. In this systematic review, we electronically searched the PubMed, Embase, ClinicalKey, Web of Science, and ScienceDirect platforms to find eligible articles. The first inspection date was on 29 December 2023 and the final update search date was on 11 June 2024. Further, we rated the quality of the included articles with Newcastle-Ottawa Scale. Based upon the aforementioned systematic review process, we have summarized the currently available evidence on the characteristics, pathophysiology, examination, and treatment of audiovestibular dysfunction related to systemic lupus erythematosus. Furthermore, we have proposed a specific steroid treatment protocol to manage audiovestibular dysfunction related to systemic lupus erythematosus. Audiovestibular dysfunction related to systemic lupus erythematosus may be responsive to adequate treatments, potentially allowing for reversibility if the disease is recognized and managed in a timely manner. Therefore, to provide clinically relevant evidence to clinicians, we have organized this literature review article to summarize the available evidence on the characteristics, pathophysiology, examination, and treatment of audiovestibular dysfunction in patients with systemic lupus erythematosus. Finally, based on our modified steroid treatment protocol, we would like to provide a new treatment strategy to clinicians to manage systemic lupus erythematosus-related audiovestibular dysfunction.

The present study explored the presence of torsional gaze-stabilization to proprioceptive neck activation in humans. Thirteen healthy subjects (6 female, mean age 25) were exposed to passive body rotations while maintaining a head-fixed, gravitationally upright, position. Participants were seated in a mechanical sled, their heads placed in a chin rest embedded in a wooden beam while wearing an eye tracker attached to the beam using strong rubber bands to ensure head stability. The body was passively rotated underneath the head both in darkness and while viewing a projected visual scene. Static torsional gaze positions were compared between the baseline position prior to the stimulation, and immediately after the final body tilt had been reached. Results showed that passive neck flexion produced ocular torsion when combined with a visual background. The eyes exhibited rotations in the opposite direction of the neck\'s extension, matching a hypothetical head tilt in the same direction as the sled. This corresponded with a predicted head rotation aimed at straightening the head in relation to the body. No such response was seen during trials in darkness. Altogether, these findings suggest that proprioception may produce a predictive gaze-stabilizing response in humans.

Disease-specific oculomotor assessments play a crucial role in the early diagnosis of hereditary cerebellar ataxias. Whereas several studies have reported on quantitative oculomotor and vestibular measurements in Friedreich\'s Ataxia (FRDA), the value of specific oculomotor paradigms remains unclear. We aimed to address this knowledge gap through a systematic literature review and providing disease-specific recommendations for a tailored set of eye-movement recordings in FRDA. MEDLINE and Embase were searched for studies reporting on quantitative oculomotor and/or vestibular measurements in FRDA-patients. Data on oculomotor and vestibular parameters were extracted and correlations with a range of clinical parameters were sought. Included studies (n = 17) reported on 185 patients. Abnormalities observed included the presence of saccadic intrusions (143/161) such as square-wave jerks (SWJ, 90/109) and ocular flutter (21/43), impaired eccentric gaze-holding (40/104), abnormal pursuit (81/93) and angular vestibulo-ocular reflex (aVOR) deficits (39/48). For visually-guided saccades (VGS), we frequently observed increases in saccade latency (27/38) and dysmetric saccades (71/93), whereas saccade velocity was more often preserved (37/43). Augmented anti-saccade (AS) latency, downbeat nystagmus and frequent macro-SWJ correlated with disease duration. Increased AS-latency and VGS-latency, frequent macro-SWJ, reduced aVOR-gain and augmented aVOR peak-latency correlated with disease severity. A broad range of oculomotor and vestibular deficits are documented in the literature. Impairments in pursuit, saccades and aVOR-responses are most commonly reported, and as such, should be prioritized as disease markers. Quantitative oculomotor testing in FRDA may facilitate early diagnosis and prove valuable in monitoring disease progression and treatment response.