Model experiment of benign paroxysmal positional vertigo mechanism using the whole membranous labyrinth
ABSTRACT Whole membranous labyrinths of bullfrogs were used in order to replicate the human vestibule. The posterior semicircular canals (PSCs) were exposed, leaving the remaining membranous labyrinth encapsulated in the otic capsule. Vibration was applied to the surface of the bony capsule using a conventional surgical drill in order to dislodge the otoconia from the utricle. The position of the preparation was controlled so that the dislodged otoconia were attached to the cupular surface. This was regarded as a cupulolithiasis model. The action potentials changed instantaneously according to the gravitational force on the cupula. When the otoconia were dislodged and held within the PSC lumen, the position of the whole preparation was changed so that the otoconia moved back and forth within the canal lumen. This is a model of canalolithiasis. The action potentials changed in combination with the otoconial movement after a latent period. Both cupulolithiasis and canalolithasis are potentially valid mechanisms of benign paroxysmal positional vertigo (BPPV). However, canalolithiasis is the most likely mechanism of BPPV, which is usually characterized by nystagmus of short duration and long latency. A vibratory stimulus was able to detach the otoconia from the utricle, suggesting that mechanical insult could be a possible etiology of BPPV.
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ABSTRACT: Objective: To examine the clinical features, age and gender distribution of patients, treatment methods, and outcomes of benign paroxysmal positional vertigo. Methods: This paper reports a review of 357 patients treated for this condition at a single institution over a duration of 5 years. Patients with posterior canal benign paroxysmal positional vertigo were divided into two groups: one group underwent the Epley manoeuvre and the other received medication. The lateral canal canalolithiasis patients were also divided into two groups: one underwent the Lempert manoeuvre and the other received medication. Lastly, the lateral canal cupulolithiasis patients were treated with medication and non-specific physical techniques. Results and conclusion: For patients with posterior canal benign paroxysmal positional vertigo, resolution time was significantly shorter in the Epley manoeuvre group than in the medication group. For the lateral canal canalolithiasis patients, resolution time was significantly shorter in the Lempert manoeuvre group than in the medication group. Resolution time was significantly longer in the lateral canal cupulolithiasis patients than in the other patients. The average age of patients increased with the number of recurrences, as did predominance in females. Average age and rate of sensorineural hearing loss were significantly higher in patients with intractable benign paroxysmal positional vertigo compared with those in the curable benign paroxysmal positional vertigo group.The Journal of Laryngology & Otology 09/2013; 127(10):1-6. DOI:10.1017/S0022215113001990 · 0.70 Impact Factor
Article: Benign Paroxysmal Positional Vertigo[Show abstract] [Hide abstract]
ABSTRACT: Benign paroxysmal positional vertigo (BPPV) is the most common and the most effectively treated vestibular disorder. The prevailing pathomechanism is canalolithiasis, which is otoconia falling in one of the semicircular canals where they move in response to changes of the head position, triggering excitation of the vestibular receptors of the affected canal. In the majority of patients with BPPV, the posterior canal is affected by canalolithiasis and there are two highly effective therapeutic maneuvers for treatment. About 20% of patients present with lithiasis of the horizontal or anterior canal. The author focuses on recent advances in diagnosis and treatment of the more rare variants of BPPV.Seminars in Neurology 07/2013; 33(3):204-11. DOI:10.1055/s-0033-1354590 · 1.78 Impact Factor