In 1861, Prosper Meniere reported pathological findings consisting of bloody exudate in the semicircular canals of a girl who had died after suffering from vertigo, tinnitus and deafness, suggesting that an inner ear lesion, in addition to cerebral accidents, could cause vertigo. In 1867, Politzer described a similar patient as having “Meniere's disease.” In 1938, Yamakawa and Hallpike independently discovered the important pathological findings of endolymphatic hydrops in patients with Meniere's disease. In 2007, Naganawa visualized endolymphatic hydrops in living patients with Meniere's disease using Gd-enhanced MRI. The further development of MRI technology is expected to yield deeper insights into the pathophysiology of Meniere's disease.
In this paper, we introduce the activities of the vertigo/dizziness center at Nara Medical University. During a 24-month period between May 2014 and April 2016, we saw 837 cases complaining of vertigo/dizziness (males: 370; females: 467). The ratios of patients with central vertigo were 1.2%. After triaging the diagnoses, we decided to focus on benign paroxysmal positional vertigo (BPPV), which accounted for 43.5% of the patients overall and 66.2% of the female patients over the age of 60 years. The ratios of vertigo/dizziness patients with unknown origins were 10.2% overall, 15.5% in the female patients over the age of 60 years. We could reduce the ratios of vertigo/dizziness patients with unknown origins less than 1.0% through the system of one-week-hospitalization for vertigo/dizziness examinations. During the 22-month period between July 2014 and April 2016, we hospitalized 106 cases with vertigo/dizziness. The highest abnormal ratios were seen as 36.4% in subjective visual vertical (SVV) tests among all vertigo/dizziness examinations except for endolymphatic hydrops tests. SVV deterioration was seen not only in patients with Meniere's disease, but also in those with BPPV.
A 67-year-old woman began to experience sudden paroxysmal dizziness (or a fainting sensation) without any auditory symptoms upon turning her head or extending her neck to look upwards. The dizziness usually resolved within a moment even if the provoking position was maintained. Nystagmus was not induced by positioning or positional change tests. An MRI examination revealed a downward shift in the cerebellar tonsil beneath the level of the foramen magnum, and the patient was diagnosed as having an Arnold-Chiari malformation (type I). The characteristic ENG findings were as follows: (1) horizontal rebound nystagmus (RN) in the dark, (2) downbeat nystagmus mainly during shifting eyes leftward or downward in the dark, (3) vertical (upward) pursuit intermingled with back-up (overshoot) saccades, (4) slightly reduced peak slow phase velocity of OKN with preserved frequencies, and (5) OKAN were within normal limits. Of special note, three different kinds of RN in the dark were concurrently recognized in a single ENG study: (i) rightward (leftward) nystagmus during rightward (leftward) gazing followed by leftward (rightward) nystagmus upon returning to a straight-ahead eye position, (ii) rightward (leftward) nystagmus followed by reversed nystagmus in the opposite direction during rightward (leftward) gazing and continued reversed leftward (rightward) nystagmus after returning to a straight-ahead eye position, and (iii) very few nystagmus events during leftward (rightward) gazing followed by a remarkable rightward (leftward) nystagmus upon returning to a straight-ahead eye position. Although the definite pathophysiological mechanisms of RN remain unclear, the compression of the cerebellar tonsil (nodulus) or flocculus/paraflocculus caused by downward herniation in the present case might be correlated with the induction of such RN.
The Head Shaking Nystagmus Test (HSNT) is an effective test for simply evaluating unilateral inner ear disorders. However, performing the HSNT passively in elderly patients can cause unexpected iatrogenic complications. For this reason, the present study compared the Active Head Shaking Nystagmus Test (AHSNT), which was performed by the patients themselves, with the air caloric test. The two tests were performed at the same visit, and the results were compared between patients diagnosed as having vestibular neuritis (VN) and those diagnosed as having sudden vertigo. The effectiveness of AHSNT for the diagnosis of VN was then examined. The Active Head Shaking Nystagmus (AHSN) score was significantly higher in the VN group than in the sudden vertigo group among the acute vertigo cases. No complications arising from the AHSNT were seen. Consequently, the test was considered to be an effective and safe means of easily differentiating VN.
Objectives: Our aim was to compare the incidence of endolymphatic hydrops (EH) between patients with unilateral/bilateral Meniere's disease (MD) and controls using a glycerol test, electrocochleogram, and 3-T magnetic resonance imaging (MRI) with intravenous gadolinium.
Methods: A total of 82 patients were diagnosed as having MD: 71 with unilateral MD (uMD), and 11 with bilateral MD (bMD). We enrolled 47 healthy volunteers as controls. The patients underwent a glycerol test, an electrocochleogram, and 3-T MRI at 4 h after the intravenous injection of gadolinium (inner ear MRI).
Results & Conclusions: The incidences of cochlear and/or vestibular EH as observed using inner ear MRI were significantly higher in the affected ears of patients with MD than in the ears of healthy controls or the contralateral ears of the patients with MD. The positive glycerol test and electrocochleogram rates were also significantly higher in the affected ear than in the contralateral ear of the patients with MD. In the present study, all the tests were useful for diagnosing MD, but inner ear MRI had the highest rate of positive results among all three tests.
A single Epley maneuver was performed for 145 patients with unilateral posterior canal-benign paroxysmal positional vertigo (BPPV) caused by canalolithiasis, and the efficacy of repositioning was evaluated using the Dix-Hallpike test on the following day. The nystagmus pattern observed during the Epley maneuver and the results of repositioning were analyzed. Of the 145 patients, 114 (79%) exhibited a resolution of BPPV, whereas 19 (13%) exhibited typical posterior canal-BPPV caused by canalolithiasis, 7 (5%) exhibited a variant of posterior canal-BPPV inducing a positional downbeat nystagmus, and the remaining 5 (3%) exhibited conversion to other forms of BPPV such as lateral canal-BPPV. During the Epley maneuver, upbeat-rotatory toward the affected ear nystagmus, downbeat-rotatory toward the healthy ear nystagmus, downbeat-rotatory toward the affected ear nystagmus, and no nystagmus were observed. However, the nystagmus pattern during the Epley maneuver was not correlated with the results of repositioning. An upbeat-rotatory toward the affected ear nystagmus indicates the movement of free debris toward the non-ampullated end of the posterior canal. A downbeat-rotatory toward the healthy ear nystagmus might imply a secondary phase of nystagmus elicited in the previous head position or the co-existence of a posterior canal-BPPV caused by canalolithiasis of the short-arm. A downbeat-rotatory toward the affected ear nystagmus indicates free debris moving toward the non-ampullated end of the anterior canal to the common crus. No nystagmus indicates that the debris did not move during the head positioning, possibly suggesting that free debris moving through the common crus did not result in the development of nystagmus.
We summarize the similarities and differences between the cochlea and vestibular endorgans in relation to mutations of genes causing hereditary hearing loss. In regard to the gene expressions associated with hereditary hearing loss in the inner ear, most of the genes expressed in the cochlea are also expressed in the vestibular end-organs. This implies that the genes associated with hereditary hearing loss also function in the vestibular endorgans, and mutations in these genes leading to hearing loss phenotypes may be associated with vestibular dysfunction phenotypes and/or symptoms. We searched the literature for the frequency of vestibular symptoms in patients with mutations in the causative genes for hearing loss. Although 67.3% of the patients with SLC26A4 mutations complained of vestibular symptoms, few patients with other mutations of genes known to cause hereditary hearing loss complained of vestibular symptoms.
SLC26A4 and COCH mutations have been reported to be the most frequently associated with vestibular dysfunction and/or symptoms. Characteristically, in patients with SLC26A4 mutations, vertigo episodes are associated with acute hearing deterioration, and in patients with COCH mutations, progressive vestibular dysfunction is associated with progressive hearing loss. Although 4% of patients with GJB2 mutations complained of vestibular symptoms, saccular dysfunction was more frequent.
It is difficult to explain the absence of vestibular symptoms in most patients with mutations of the causative genes for hearing loss?. Possible explanations for this inconsistency are the presence and functioning of other molecules to compensate for the functional loss of sensory activity in the vestibular end-organs; congenital or slowly progressive vestibular dysfunction could be compensated by visual and somatosensory input. Furthermore, the vestibular sensory system may have a lower sensitivity than the auditory system. Further studies are required to elucidate the effects of mutations linked to deafness on the vestibular functions.
Acute low-tone sensorineural hearing loss (ALHL) is the most common among the causes of acute sensorineural hearing loss. It is well known that some cases of ALHL eventually develop typical or atypical Meniere's disease. Recently, gadolinium-enhanced inner ear MRI has revealed that endolymphatic hydrops is frequently seen not only in Meniere's disease, including the atypical type, but also in cases of ALHL. Therefore, it can be said that one of the fundamental differences between ALHL and Meniere's disease is whether the condition is episodic or not. We propose to conduct a re-evaluation in the future of the classification of the causes of primary endolymphatic hydrops, such as ALHL and Meniere's disease, by gadolinium-enhanced inner ear MRI, as proposed by Gürkov.
Meniere's disease is diagnosed by the clinical triad of episodic vertigo, fluctuating hearing loss and tinnitus. Meniere's disease sometimes develops initially as acute low-tone sensorineural hearing loss, which is characterized by hearing loss limited to low-tone frequencies, in the absence of vertigo. Acute low-tone sensorineural hearing loss, with its favorable prognosis, is a distinct clinical entity from idiopathic sudden sensorineural hearing loss. However, it frequently relapses, with fluctuating hearing loss, in the absence of vertigo. Finally, Meniere's disease is diagnosed when these patients with acute low-tone sensorineural hearing loss develop episodic vertigo. According to epidemiological studies, about 10% of patients with acute low-tone sensorineural hearing loss suffer from Meniere's disease. It is assumed that endolymphatic hydrops is the common pathophysiology of both Meniere's disease and acute low-tone sensorineural hearing loss. In this review, the similarities and differences between acute low-tone sensorineural hearing loss and Meniere's disease are discussed.