Calcium functional imaging with high-resolution CT in the inner ear

Although the otolith and otolith organs correlate with vertigo and instability, there is no method to investigate them without harmful procedures. We will create the technique for 3D microanatomical images of them, and investigate the in vivo internal state and metabolisms. The otolith and otolith organs images were reconstructed from a texture synthesis algorithm under the skull volume rendering algorithm using a cutting-plane method. The utricular macula was elongated pea-shaped. The saccular macula was almost bud-shaped. The changes in the amount of CaCO3 in the maculae and the endolymphatic sac showed various morphologies, reflecting the balance status of each subject. Both shapes and volumes were not always constant depending on time. In Meniere’s disease (MD), the saccular macula was larger and the utricular macula was smaller. In benign paroxysmal positional vertigo (BPPV), the otolith increased in the utricular macula but did not change much in the saccular macula. The saccule, utricle, and endolymphatic sac were not constantly shaped according to their conditions. These created 3D microanatomical images can allow detailed observations of changes in physiological and biological information. This imaging technique will contribute to our understanding of pathology and calcium metabolism in the in vivo vestibulum.

Acoustic ocular vestibulat evoked miogenic ptotentials (AC-oVEMP) in assessment of vertigo

Evaluation of acoustic vestibular evoked myogenic potentials (AC-VEMPs) is one of the tests performed to assess the function of the balance system. Evaluation of acoustic ocular vestibular evoked myogenic potentials (AC-oVEMPs) consists in the measurement of potentials evoked within oculomotor muscles, particularly the inferior oblique muscles (the most superficial muscles) with impulses being transmitted along the superior branch of the vestibular nerve from the utricular macula. Despite the fact that the measurement of oVEMPs was introduced relatively recently, it has found widespread use as a diagnostic tool in otology and neurotology. Despite the growing number of literature reports, the methodology of the test and the methods for the interpretation of its results are still subject to debate. This article is dedicated to various aspects of AC-oVEMP tests, including the methodology of the test, interpretation of its results and potential use in the diagnostics of vertigo.

Experimental study on the aetiology of benign paroxysmal positional vertigo due to canalolithiasis: comparison between normal and vestibular dysfunction models

Objectives:Using American bullfrog models under normal conditions and under vestibular dysfunction, we investigated whether mechanical vibration applied to the ear could induce otoconial dislodgement.Methods:Vibration was applied to the labyrinth of the bullfrog using a surgical drill. The time required for the otoconia to dislodge from the utricular macula was measured. Vestibular dysfunction models were created and the dislodgement time was compared with the normal models. The morphology of the utricular macula was also investigated.Results:In the normal models, the average time for otoconial dislodgement to occur was 7 min and 36 s; in the vestibular dysfunction models, it was 2 min and 11 s. Pathological investigation revealed that the sensory hairs of the utricle were reduced in number and that the sensory cells became atrophic in the vestibular dysfunction models.Conclusion:The otoconia of the utricle were dislodged into the semicircular canal after applying vibration. The time to dislodgement was significantly shorter in the vestibular dysfunction models than in the normal models; the utricular macula sustained significant morphological damage.

Histological effects of intratympanic gentamicin on the vestibular organ of guinea pigs

Background:Transtympanic administration of gentamicin may be suitable to achieve unilateral vestibular ablation, in order to control unilateral Ménière's disease. In low doses, gentamicin appears to affect selectively the vestibular system, with relative sparing of the cochlea. An experimental study on guinea pigs was conducted to determine what single dose of gentamicin would produce a unilateral vestibular organ lesion when applied to the middle ear.Study design:Experimental and prospective.Methods:Four groups of guinea pigs received different gentamicin doses (1, 5, 10 and 25 mg) administered to the middle ear. The animals' vestibular organs were then assessed by scanning electron microscopy, in order to quantify the level of vestibular damage.Results:Study of the utricular macula and the ampullar crista of the lateral semicircular canal revealed vestibular neuroepithelial lesions in all infused ears.Conclusions:The severity of the vestibular neuroepithelial lesions was dose-dependent. Lower gentamicin doses were observed to damage vestibular structures more than cochlear structures.