We introduce a method to diagnose sensorineural hearing loss and vestibular disorder using magnetic resonance imaging (MRI). The main pathological finding in patients with Meniere's disease is distention of the entire endolymphatic system, i.e., endolymphatic hydrops, and its diagnosis depends primarily upon a history of fluctuating hearing loss and tinnitus, as well as episodic vertigo associated with vegetative symptoms. Therefore, the development of a practical tool to obtain objective evidence of the existence of endolymphatic hydrops is important. We applied a high-resolution magnetic resonance imaging device running at 2.11 T, 4.7 T, and 7.05 T for the non-invasive depiction of the fine structure of the inner ear in humans and guinea pigs. We have succeeded in depicting both the basilar and Reissner's membranes of the basal turn of the cochlea. In this paper, we present our results using high-resolution MRI and discuss the current status in this field. We suggest the possibility of using MRI for the morphological and functional diagnosis of inner ear pathology in the near future.
A 12-year-old male experienced left-sided hearing impairment, tinnitus, and vertigo after being hit by a volleyball. Pure tone audiometry showed severe, mixed left hearing loss and nystagmus to the right side. We diagnosed perilymphatic fistula and treated it conservatively. After ten days, his vertigo had disappeared and hearing on his left side showed improvement except at 2,000 and 8,000 Hz. However, he experienced slight dizziness after discharge from our hospital. About eleven months later, because of severe vertigo, he again came to our hospital. We diagnosed benign paroxysmal positional vertigo (BPPV) based on his symptoms and the characteristic nystagmus. We performed the Epley maneuver, and his vertigo and nystagmus disappeared the next day. Exploratory tympanotomy was carried out, but no sign of a perilymphatic fistula was detected. He experienced BPPV again, and so we tried the Epley and Lempert maneuver. We believed his prolonged dizziness was due to a partial collapse of the utricular wall, a condition called floating labyrinth. This phenomenon may occur with migration of otoliths from the utricle, leading to BPPV.
Three patients suspected of having intractable Meniere's disease had shown no effect via the usual treatment of inner ear hydrops for 7, 13, and 15 years. They were re-evaluated and managed for neurovascular compression syndrome (NVC) of the 8th cranial nerve based on their distinctive vertigo, hearing loss, and tinnitus, followed by symptomatic relief with cinnarizine or a papaverine-containing drug. In addition to these symptoms, two of three patients showed ipsilateral displacement of the basilar artery (BA) on the axial view of MRI. Patients with NVC of the 8th cranial nerve may show rapid relief from sudden onset, recurrent vertigo with severe nystagmus, even in the case of canal paresis, marked fluctuating hearing loss with or without vestibular symptoms, and slowly progressive (unrecognized) hearing loss accompanied by tinnitus of a varying intesity. Patients have experienced symptomatic relief with carbamazepine, cinnatizine, or papaverine-containing drugs. Suspected cases of NVC have shown dolichoectatic ipsilateral convexity of the BA at the level of the internal auditory meatus on the axial view on MRI at a rate of 86.5%, which has been suggested to serve as a diagnostic feature of NVC.
Most cases of benign paroxysmal positional vertigo (BPPV) involve the posterior or horizontal semicircular canal, whereas that involving the anterior semicircular canal is rare. We herein report a case of anterior BPPV that was difficult to diagnose and treat. The case was a 16-year-old male. Vertigo while lying down appeared in November 2003, and he consulted The Department of Neurosurgery of our hospital on January 13, 2004. As there was neither central nervous system signs nor abnormal finding on brain computerized tomography, he was referred to our department. At the initial visit, downbeat nystagmus was noted in the suspensory head position. Central nystagmus was suspected, head MRI was undertaken. Since there was no apparent abnormality on imaging, a wait-and-see approach was taken under a diagnosis of idiopathic vertigo. On November 22, 2005 (18 years old), downbeat nystagmus with a clockwise movement (from the examiner) was seen in the left and right head-down position using the Dix-Hallpike method. On review of the clinical history, it was noted that he had hit his head forcefully during a backflip when he was fourteen years old, and he had a habit of lying in a prone position in bed. Therefore, we diagnosed left anterior BPPV. Non-specific exercise therapy was performed but not effective. A modified canalith repositioning maneuver was conducted three times and we instructed him not to remain in a prone position in bed. As a result, the subjective symptoms disappeared. The need to use the Dix-Hallpike method in diagnosing BPPV was reconfirmed. In addition, detailed history taking including the habitual position in bed is useful for diagnosis and treatment.