Characterization of Vestibular Perception in Patients with Persistent Postural-Perceptual Dizziness.

OBJECTIVE: To assess vestibular (i.e., passive self-motion) perception in patients diagnosed with persistent postural-perceptual dizziness (PPPD). STUDY DESIGN: Case-controlled, cross-sectional, observational investigation. SETTING: Single-center laboratory-based study. PATIENTS: Thirteen patients with PPPD, 13 age-matched healthy control volunteers. Of those with PPPD, eight had co-occurring vestibular migraine (VM). INTERVENTIONS: All participants completed a vestibular threshold test battery reflecting perception with predominant inputs from ( a ) the otoliths (1-Hz interaural y -axis translation, 1-Hz superior-inferior z -axis translation), ( b ) the semicircular canals (2-Hz yaw rotation, 2-Hz tilts in the planes of the vertical canal pairs), and ( c ) and canal-otolith integration (0.5-Hz roll tilt). MAIN OUTCOME MEASURES: Direction-recognition thresholds for each vestibular threshold test condition. RESULTS: Across all patients with PPPD, higher thresholds for superior-inferior z -translations thresholds in comparison to age-matched healthy control participants were identified ( p < 0.001). Those patients with co-occurring VM and PPPD (PPPD/+VM) displayed significantly higher z -translation thresholds ( p = 0.006), whereas patients with PPPD without VM (PPPD/-VM) displayed significantly higher roll tilt thresholds ( p = 0.029). CONCLUSIONS: Patients with PPPD did not display a global worsening of passive self-motion perception as quantified by vestibular perceptual thresholds. Instead, patients with PPPD displayed elevated thresholds for only roll tilt and z -translation thresholds, with the relative change in each threshold impacted by the co-occurrence of VM. Because both z -translation and roll tilt motions are reliant on accurate gravity perception, our data suggest that patients with PPPD may exhibit impaired processing of graviceptive cues.

A possible link between intracranial lipomas and localization-related relapses in multiple sclerosis.

Intracranial lipomas are congenital malformations representing less than 0.5% of intracranial tumors. They are found incidentally and are asymptomatic in the majority of patients. Here we present three patients with Multiple sclerosis (MS) and intracranial lipomas (IL). The patients showed increased flares and burden of disabling and worsening MS symptoms with cognitive, neurovestibular dysfunction, and gait alterations associated with the localization of the Lipoma. The parenchyma near the Lipomas showed areas of demyelination and atrophy. We postulate that the location and content of the Lipomas may participate in the pathophysiology of MS symptoms in these patients. We conclude that in concurrent IL and MS, the lipomas localization may provoke incapacitating relapses.

Diagnosis and management of lateral semicircular canal benign paroxysmal positional vertigo.

OBJECTIVE: Describe the diagnosis, treatment, and outcome of a group of 20 patients with lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV). STUDY DESIGN AND SETTING: Retrospective review of 20 patients with LSC-BPPV (10 with geotropic and 10 with apogeotropic nystagmus) presenting to a tertiary balance center. Diagnosis was confirmed with infrared nystagmography in Dix-Hallpike positioning tests and supine positional tests. Patients were treated with one or more particle repositioning maneuvers. RESULTS: Addition of supine positional nystagmus tests to Dix-Hallpike positioning testing improves sensitivity in the diagnosis of LSC-BPPV. Treatment outcomes in the apogeotropic LSC-BPPV group were poorer than the geotropic LSC-BPPV group. SIGNIFICANCE: Adding supine positional testing to routine vestibular diagnostic testing will increase the identification of LSC-BPPV. Apogeotropic LSC-BPPV is more challenging to treat.

Canalith repositioning for benign paroxysmal positional vertigo.

OBJECTIVE: To evaluate the efficacy of canalith repositioning maneuvers (Semont, Epley, and modified maneuvers) in the treatment of posterior canal benign paroxysmal positional vertigo (BPPV) in comparison to the rate of resolution in the untreated control cohort. DATA SOURCES: Source articles were identified by a MEDLINE search of English language sources before 2004 plus manual crosschecks of bibliographies from identified articles, selected national meeting abstracts, review article references, and textbook chapters. STUDY SELECTION: Each controlled trial that compared canalith repositioning patients to untreated control subjects in posterior canal benign positional vertigo (blinded and unblinded) was reviewed for inclusion. DATA EXTRACTION: Data were abstracted systematically, scaled on validity and comparability, and cross-checked independently by another author. DATA SYNTHESIS: Studies were combined with fixed effects meta-analysis to estimate spontaneous resolution, 95% confidence intervals (CI) of effect size, and heterogeneity. CONCLUSION: Canalith repositioning is more effective than observation alone for the treatment of benign paroxysmal positional vertigo, despite spontaneous resolution rates of one in three at 3 weeks. Public health implications are discussed, based on the high frequency of unrecognized BPPV reported in elderly patients, and the improvements after canalith repositioning in postural control and health-related quality of life (SF 36 Health Survey) documented in the literature.

Lateral sinus thrombosis associated with zoster sine herpete.

Herpes zoster results from reactivation of the varicella zoster virus (VZV). Zoster sine herpete (ZSH) is an uncommon manifestation of VZV infection and presents with similar symptoms but without the vesicular rash. We describe an unusual case of lateral sinus thrombosis (LST) that developed during the clinical course of ZSH in the C2 distribution. A 55-year-old woman presented with a 3-day history of left temporal and postauricular pain, nausea, vomiting, and mild photophobia. She denied otalgia, otorrhea, and hearing loss. Examination revealed hyperesthesia in the left C2 nerve root distribution without evidence of herpetic rash. A computed tomography scan showed minimal fluid in the left mastoid cavity (not mastoiditis) and thrombus within the left lateral and sigmoid dural sinus. Magnetic resonance imaging and magnetic resonance angiogram confirmed these findings. Laboratory studies revealed elevated neurotrophic immunoglobulin G levels to VZV. Hypercoagulable studies were normal. She was subsequently treated with Neurontin, acyclovir, and anticoagulation. Her symptoms improved, and she was discharged 3 days later. LST is generally a complication of middle ear infection. Nonseptic LST, however, may result from dehydration, oral contraceptive use, coagulopathy, or thyroid disease. This unusual case raises the suspicion that thrombosis resulted from VZV associated thrombophlebitis in the ipsilateral cerebral venous sinuses along the second cervical nerve root distribution. A high index of suspicion is necessary in such cases so that a different treatment course can be identified and antiviral medication initiated promptly.

Effect of gravity on the caloric stimulation of the inner ear.

Robert Barany won the 1914 Nobel Prize in medicine for his convection hypothesis for caloric stimulation. Microgravity caloric tests aboard the 1983 SpaceLab 1 mission produced nystagmus results that contradicted the basic premise of Barany's convection theory. In this paper, we present a fluid structural analysis of the caloric stimulation of the lateral semicircular canal. Direct numerical simulations indicate that on earth, natural convection is the dominant mechanism for endolymphatic flow. However, in the microgravity environment of orbiting spacecraft, where buoyancy effects are mitigated, an expansive convection becomes the sole mechanism for producing endolymph motion and cupular displacement. Transient 1 g and microgravity case studies are presented to delineate the different dynamic behaviors of the 1 g and microgravity endolymphatic flows. The associated fluid-structural interactions are also analyzed based on the time evolution of cupular displacements.