The effect of a first-generation H1-antihistamine on postural control: a preliminary study in healthy volunteers.

First-generation H1-antihistamines are known to cause fatigue and drowsiness, due to their poor receptor selectivity and their high penetration rate of the blood-brain barrier. However, little is known about the effects of first-generation H1-antihistamines on postural stability. The purpose of this study was to evaluate the effects of d-chlorpheniramine on postural stability using posturography with and without foam rubber.

Ocular vestibular evoked myogenic potentials in response to air-conducted sound and bone-conducted vibration in vestibular schwannoma.

Objective: To clarify the origin and pathways of ocular vestibular evoked myogenic potentials (oVEMPs) to air-conducted sound (ACS), we compared the results of oVEMPs with ACS, with oVEMPs with bone-conducted vibration (BCV), cervical VEMPs (cVEMPs) with ACS, and the caloric test in patients with unilateral vestibular schwannoma (VS).

Study Design: Retrospective review.

Setting: Tertiary referral center.

Evidence for the utricular origin of the vestibular short-latency-evoked potential (VsEP) to bone-conducted vibration in guinea pig.

Previous studies have shown that the vestibular short-latency-evoked potential (VsEP) in response to the brief head acceleration stimulus is a compound action potential of neurons innervating the otolith organs. However, due to the lack of direct evidence, it is currently unclear whether the VsEP is primarily generated by the activity of utricular or saccular afferent neurons, or some mixture of the two. Here, we investigated the origin of the VsEP evoked by brief bone-conducted vibration pulses in guinea pigs, using selective destruction of the cochlea, semicircular canals (SCCs), saccule, or utricle, along with neural blockade with tetrodotoxin (TTX) application, and mechanical displacements of the surgically exposed utricular macula.

The effect of systemic administration of desmopressin on cochlear function in guinea pigs.

Conclusions: Systemic desmopressin (dDAVP) administration in guinea pigs for up to 2 weeks induced only minor or no significant changes in cochlear sensitivity, suggesting that other factors may be required to induce the cochlear dysfunction that is usually associated with endolymphatic hydrops.

Objectives: To investigate the effects of chronic systemic administration of dDAVP, a synthetic analog of vasopressin, on cochlear sensitivity in guinea pigs.

Methods: dDAVP was administered subcutaneously via a mini-osmotic pump, at a rate of 0.

Diagnostic usefulness of multifrequency tympanometry for Ménière's disease.

Multifrequency tympanometry (MFT) is the measurement of the impedance of the middle ear transmission system at a wide range of frequencies from 200 Hz to 2 kHz. A potential use of MFT as a new diagnostic tool for detecting endolymphatic hydrops has recently been reported. However, its clinical usefulness for diagnosing Ménière's disease (MD) remains unclear.

Effect of vestibular dysfunction on the development of gross motor function in children with profound hearing loss.

Objective: To evaluate the function of the superior and inferior vestibular nerve systems in children with profound sensorineural hearing loss, and to assess the influence of dysfunction of each vestibular nerve system on the development of gross motor function.

Study Design: Retrospective study.

Setting: A tertiary referral center.

Effect of severity of vestibular dysfunction on postural instability in idiopathic bilateral vestibulopathy.

Conclusions: Foam posturography reveals that idiopathic bilateral vestibulopathy (IBV) significantly affects postural stability. Instability was more severe in patients with damage to both of the vestibular nerve systems. Residual function in the spared vestibular nerve system might contribute to postural stability in IBV.

Changes in cochlear function during acute endolymphatic hydrops development in guinea pigs.

Previous studies have injected artificial endolymph into scala media in anaesthetized guinea pigs as an acute model of endolymphatic hydrops. Here, we have injected artificial endolymph into scala media in guinea pigs at rates of 40-80 nl/min, whilst monitoring Compound Action Potential (CAP) thresholds, the Summating Potential (SP)/CAP ratio, Cochlear Microphonic (CM) distortion, low-frequency modulated Distortion Product Otoacoustic Emissions (DPOAEs), and the Endocochlear Potential (EP). We found that abrupt recovery of CAP thresholds, SP/CAP ratio, and CM and DPOAE asymmetric distortion could occur several times during a single injection of less than 3 μl, suggesting that endolymph pressure could periodically decrease while the injection was ongoing.

Clinical characteristics of inferior vestibular neuritis.

Conclusions: Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and its clinical characteristics are unique.

Objectives: To clarify clinical characteristics of IVN in comparison with conventional VN.

Methods: This was a retrospective case series review.

Different effects of head tilt on ocular vestibular-evoked myogenic potentials in response to bone-conducted vibration and air-conducted sound.

The ocular vestibular-evoked myogenic potentials (oVEMPs) in response to air-conducted sound (ACS) and bone-conducted vibration (BCV) have recently been used to assess otolith-ocular pathways in humans. Although the oVEMPs to BCV are considered to reflect the function of the utricle and superior vestibular pathway, the pathway of the oVEMPs to ACS remains controversial. In this study, we compared the effect of different head positions in the roll plane on oVEMPs in response to BCV and ACS in 20 normal subjects.

Bilateral vestibulopathy with dissociated deficits in the superior and inferior vestibular systems.

Objectives: The aim of this study was to reveal the clinical characteristics of dissociated bilateral vestibulopathy (BV) affecting the superior vestibular nerve system on one side and the inferior vestibular nerve system on the other side. It is probable that BV does not always show bilateral deficits of the same vestibular nerve system.

Methods: In a retrospective study of 2,752 consecutive new patients, 1,560 patients had undergone both caloric testing and cervical vestibular evoked myogenic potential testing.

Assessment of postural stability using foam posturography at the chronic stage after acute unilateral peripheral vestibular dysfunction.

Objective: To investigate the utility of foam posturography for assessing equilibrium at the chronic stage after acute unilateral peripheral vestibulopathy.

Methods: Thirty-four consecutive patients (16 patients at the chronic stage) with acute unilateral peripheral vestibulopathy and absent caloric responses unilaterally were recruited, along with 66 healthy control subjects. Two-legged stance tasks were performed in 4 conditions: with eyes open or closed, with or without using foam rubber.

Developmental changes in the expression of Κv1 potassium channels in rat vestibular ganglion cells.

The primary afferent neurons of the vestibular ganglion convey sensory information from hair cells in the semicircular canals and otolith organs to the vestibular nuclei, the adjacent brainstem and the cerebellum. The intrinsic firing properties of vestibular ganglion cells (VGCs) are heterogeneous and have been classified into phasic, intermediate and tonic firing types on the basis of their response to injected depolarizing currents. A previous study from our group showed that the proportion of phasic discharging VGCs decreased during the first postnatal weeks.

The mitochondrial A3243G mutation involves the peripheral vestibule as well as the cochlea.

Objectives/hypothesis: To evaluate vestibular function in patients with the mitochondrial A3243G mutation.

Study Design: Data from patients with the A3243G mutation attending an academic tertiary referral center were prospectively recorded.

Methods: The clinical histories of 13 unrelated patients with the mitochondrial A3243G mutation (six mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; and seven maternally inherited diabetes and deafness) were recorded, in particular their history of vestibular symptoms.

Responsiveness of rat vestibular ganglion neurons to exogenous neurotrophic factors during postnatal development in dissociated cultures.

We examined the responsiveness of rat vestibular ganglion neurons (VGNs) to exogenous neurotrophic factors, BDNF, NT-3, and GDNF, during postnatal development in dissociated cultures. VGNs were obtained from postnatal days (P) 1, 3, 7, and 14. After two days in culture, the survival of VGNs in control cultures without any exogenous neurotrophic factors was greater in younger (P1 or 3) rats than older (P7 or 14) rats.

Cephalic tetanus presenting as acute vertigo with bilateral vestibulopathy.

Cephalic tetanus is a rare form of tetanus, defined by paralysis of more than one cranial nerve. The seventh cranial nerve is the most frequently involved. We report a 58-year-old man with cephalic tetanus and bilateral vestibulopathy.

Effect of the canalith repositioning procedure on subjective visual horizontal in patients with posterior canal benign paroxysmal positional vertigo.

Conclusion: Substantial numbers of patients with posterior canal benign paroxysmal positional vertigo (p-BPPV) have signs of utricular dysfunction at baseline. This improves after performing the canalith repositioning procedure.

Objective: To evaluate the changes of subjective visual horizontal (SVH) in patients with p-BPPV before and after treatment with the canalith repositioning procedure.

The ocular vestibular-evoked myogenic potential to air-conducted sound; probable superior vestibular nerve origin.

Objective: Intense air-conducted sound (ACS) elicits an ocular vestibular-evoked myogenic potential (oVEMP), and it has been suggested that it does so by stimulating saccular receptors and afferents in the inferior vestibular nerve and so activating a crossed sacculo-ocular pathway. Bone conducted vibration (BCV) also elicits an oVEMP probably by activating utricular receptors and a crossed utriculo-ocular pathway. Are there two separate pathways mediating oVEMPs for ACS and BCV? If saccular receptors and afferents are primarily responsible for the oVEMP to ACS, then the oVEMP to ACS should be normal in patients with reduced or absent utricular function--unilateral superior vestibular neuritis (SVN).

Functional ligand-gated purinergic receptors (P2X) in rat vestibular ganglion neurons.

The expression of purinergic receptors (P2X) on rat vestibular ganglion neurons (VGNs) was examined using whole-cell patch-clamp recordings. An application of adenosine 5'-triphosphate (ATP; 100microM) evoked inward currents in VGNs at a holding potential of -60mV. The decay time constant of the ATP-evoked currents was 2-4s, which is in between the values for rapidly desensitizing subgroups (P2X1 and P2X3) and slowly desensitizing subgroups (P2X2, P2X4, etc.

Effects of unilateral dysfunction of the inferior vestibular nerve system on postural stability.

Objective: To investigate whether disorders of the inferior vestibular nerve (IVN) system affect postural stability.

Method: Two-legged stance tasks were performed by patients with unilateral peripheral vestibulopathy (n=108) in four conditions: eyes open or eyes closed, with or without foam rubber. We examined six parameters: the velocity of movement of the center of pressure and the envelopment area determined by tracing the movement in the eyes closed/foam rubber condition, Romberg's ratio of velocity and area with foam rubber, and the foam ratios (ratios of a measured parameter with to without the foam rubber) of velocity and area with eyes closed.

Ocular vestibular evoked myogenic potentials to bone-conducted vibration in vestibular schwannomas.

Background: Vestibular schwannoma (VS) arises from either the superior or the inferior vestibular nerve and causes vestibular dysfunction to various degrees. Recently, ocular vestibular evoked myogenic potentials to bone-conducted vibration (oVEMPs to BCV) have attracted much interest as a new clinical test for otolith-ocular pathway function. Because it is unclear whether the oVEMPs to BCV primarily originate from activation of the superior or the inferior vestibular nerve, the results in patients with VS might enlighten us concerning the origin of oVEMPs to BCV.

Frequency tuning properties of ocular vestibular evoked myogenic potentials.

Loud air-conducted sound or bone-conducted vibration produces vestibular-dependent electromyographic responses both in the cervical muscles (cervical vestibular evoked myogenic potentials) and in the extraocular muscles (ocular vestibular evoked myogenic potentials; oVEMPs). Although previous frequency tuning measurements of cervical vestibular evoked myogenic potentials have provided important information for a clinical application, those of oVEMPs have rarely been studied. We explored the frequency tuning properties of oVEMPs in 12 healthy participants.

The firing properties of vestibular ganglion cells in heterozygous BDNF null mice.

We examined the firing properties of vestibular ganglion cells (VGCs) acutely isolated from wild or heterozygous brain-derived neurotrophic factor null mice, using the patch-clamp technique. VGCs obtained from wild-type mice showed diverse firing properties during sustained membrane depolarization; approximately half of the neurons exhibited strong adaptation, generating just a single spike or a few spikes (phasic type), whereas approximately one-fourth of the neurons showed moderate adaptation or tonic firing (tonic type). In heterozygous mice, the majority of VGCs belonged to the tonic type, the rate of which was significantly different from that of wild-type.

Assessment of diagnostic accuracy of foam posturography for peripheral vestibular disorders: analysis of parameters related to visual and somatosensory dependence.

Objectives: Simple tests to detect peripheral vestibulopathy might be practically useful before conducting elaborate examinations. The purpose of this study was to assess the diagnostic accuracy of foam posturography for peripheral vestibulopathy, with emphasis on visual and somatosensory dependence.

Methods: Two-legged stance tasks were conducted in patients with unilateral (n=68) and bilateral (n=16) vestibulopathy and healthy controls (n=66), under four conditions; eyes open with and without the foam rubber, and eyes closed with and without the foam rubber.