The caloric test is a clinical examination to evaluate the activities of vestibular function by applying thermal stimulation to the external ear canal. This test is widely performed to determine the causative side and the level of vertigo, since it used to be the only way to stimulate the right or left ear separately. The amount of thermal stimulation is determined by the amount of thermal energy transmitted to the inner ear, i.e., the medium (water or air), the temperature difference from the ear drum, the length of time of stimulation, and the amount of flow of the medium. The thermal stimulation induces nystagmus, neck torsion, nausea and sensations of vertigo. Because nystagmus is a pure reflexive response dependent on the strength of the stimulus, caloric nystagmus has been developed as an examination of vestibular system activities. For clinical examination, the procedure and the criteria for diagnosis need to be determined not only for patients, but also for the examiners. To apply a thermal stimuli, a small amount of cold water close to room temperature is recommended, i.e.. 5mL of tap water with a temperature of 20°C. The water should be used to fill the ear canal for 20 sec and then to bring the head 30°anteflex from the supine position (Uemura). If the caloric nystagmus is recorded using EOG or VOG, the maximal velocity of the slow phase is the best indicator to show the inner ear activity, since it is correlated with the strength of the stimulus. To obtain a stable and strong response, the recording must be done while the eyes are open and the subject is in complete darkness. During the caloric response, the examinee should look at a visual target for 10 seconds to check the activity of the central vestibular system; the slow phase velocity should decrease to about 50% (visual suppression test of Takemori.) Turning the head 45° to the right or left will suppress or potentiate the vertical component, indicating the participation of the vertical semicircular canals. When the caloric nystagmus is completed, the examinee should be asked to sit up at 90°; a horizontal nystagmus to the opposite side will then appear (“second phase”). This nystagmus shows the stored activity in the central vestibular system. If the inner ear activity is the same in both ears, the right-left difference of the ”second phase” will reflect the central vestibular asymmetry called the Direction Preponderance (DP). A slow phase velocity of 20-50°/s with right-left differences less than 20% or no spontaneous nystagmus is considered a normal response. A velocity of less than 10°/s is considered a weak canal response (canal paresis, CP), while a loss of visual suppression or a response that is too strong (more than 60°/s ) is considered to indicate a central vestibular lesion on that side. The mechanisms producing caloric nystagmus are discussed in the present report.
Along with Epley's canalith repositioning maneuver, the Semont maneuver is also recognized as an effective physical therapy for benign paroxysmal positional vertigo. However, the details of this maneuver are not well known, presumably because of the obscurity of the original description by Semont et al. In Japan, the “Semont liberatory maneuver,” as described by Brandt, is accepted as the “original” Semont maneuver. However, the two maneuvers are not identical. The aim of this paper was to reproduce the original procedure of Semont's as presented by A. Semont himself at the 10th Nagoya Otorhinolaryngological Forum held in Nagoya, Japan, in 2006. This lecture clarified some obscure points in the original paper; however, the procedure described at the forum was not a detailed reproduction of the original Semont maneuver, but was somewhat more complicated. Also of note, Semont decisively denied the cupulolithiasis theory and explained the usefulness of his maneuver according to the canalolithiasis theory.
To investigate the equilibrium function of elderly patients experiencing dizziness caused by age-dependent physiological vestibular dysfunction (presbyastasis) and to evaluate the effects of a vestibular rehabilitation program, the author conducted a new balance training program, referred to as the cross test. Nine patients over the age of 65 years who had presbyastasis and who had complained of equilibrium dysfunction for at least 6 months were enrolled in this study. A standing balance training system with a gravicorder was used to examine the patients' equilibrium. The cross test indicates the equilibrium function based on ankle mobility and the center of gravity when individuals successively move forward, backward, right, and left on the gravicorder. The cross test was performed every one or two months for a total of at least 5 times; the results were then analyzed statistically. After participating in the vestibular rehabilitation program, the range of ankle motion improved in all 9 patients, compared with the pretraining values (p<0.001). These findings suggested that the cross test is a reliable method for estimating equilibrium function and the effects of a balance training program in patients with presbyastasis. Furthermore, the test appears to be associated with a prompt improvement in equilibrium dysfunction and thus may be an effective therapeutic option, in conjunction with medication and conventional vestibular training programs.
We compiled clinical statistics for recent cases of vertigo and dizziness treated at our otolaryngological clinic. Peripheral vestibular disease accounted for 71.7% of the cases, while central vestibular disorder accounted for 6.9%. Regarding the frequency of disease, benign paroxysmal positional vertigo (BPPV) was the most common (47.7%), followed by Meniere's disease (15.4%); these frequencies were similar to those reported at other institutions. Regarding the affected part among the patients with BPPV, the most frequently encountered type was lateral canal-type BPPV (canalolithiasis type), followed by posterior canal-type, lateral canal-type (cupulolithiasis type), and anterior canal-type BPPV. The healing period did not differ significantly among the types of BPPV. The overall relapse rate was approximately 40%, which was similar to the rates reported for other institutions. Among the BPPV patients who initially received treatment in a clinical department other than otolaryngology, 50.7% received a head CT examination that was of no clinical value to the diagnosis of BPPV. It was suggested that the role of the otolaryngologist that BPPV diagnosis was possible in nystagmus views, was important in BPPV medical treatment.
Orthostatic headache is a key symptom of cerebrospinal fluid leakage. Other features may include neck pain, interscapular pain, nausea, vomiting, dizziness, tinnitus, and blurred vision. Various psychological or mental symptoms such as depression, forgetfulness, and a decreased power of concentration may also occur in this syndrome. When these symptoms are prominent or precede the onset of other symptoms, the clinical picture of this syndrome becomes more complicated, leading to misdiagnosis or long-term neglect. Of note, patients with cerebrospinal fluid leakage who visit an otolaryngological or oto-neurological clinic usually have atypical manifestations. In the vast majority of our patients with this syndrome, the presenting symptom is dizziness, not headache. The presenting symptom of the 30-year-old female patient who is the subject of this report was also dizziness. The patient's initial symptom was a stomachache; however, medical therapy was ineffective, and endoscopic examination of the stomach revealed no abnormalities. The stomachache was diagnosed as resulting from psychological or mental causes. Other manifestations also indicated that the patient suffered from mental depression. Antidepressants and sleeping pills were prescribed, but no improvement was noted. Dizziness, unsteadiness, nausea, and loss of concentration occurred insidiously and worsened after the patient hit her occiput strongly against a wall during an attack of hyperventilation. The patient also complained of headache. The patient was referred to our clinic by a local otolaryngologist. At the time of the patient's initial visit, a slight unsteadiness was noted while the patient stood and walked, but other vestibular functions were normal. A neurological examination did not show any abnormalities. Psychological testing confirmed the presence of depression. The patient, presumably because of her depression, was dispirited and never discussed her symptoms voluntarily. However, a detailed history revealed that the patient had an orthostatic headache, paresthesia in both hands, blurred vision, and forgetfulness. Several episodes of falls at a pool-side occurring as early as during elementary school were also noted. The diagnosis of cerebrospinal fluid leakage was confirmed by brain MRI and 111In-cisternography examinations. An epidural blood patch was performed three times. The patient recovered from her depression; although a mild headache and nausea persisted, all the patient's other symptoms, including dizziness and unsteadiness, improved dramatically. The patient returned to work.
Intense brief sound evokes short-latency myogenic potentials around the eyes in humans. These potentials are named ocular vestibular-evoked myogenic potentials (OVEMP), but the origin and pathway of these responses remain unclear. To establish an animal model for OVEMP, we recorded sound-evoked potentials around the eyes using awake monkeys. Two macaque monkeys were used in the research. A pair of electrodes was attached under an eye, and each animal was made to gaze at the monitor with their eyes in a fixed position while sitting in a primate chair. When a 135-dB SPL air-conducted 500-Hz tone burst was applied, the peak latencies of the first negative and second positive waves were 10.4 msec and 13.7 msec. The peak latency of the first negative wave did not change when the frequency was changed. The threshold of the myogenic potentials at a frequency of 500 Hz was lowest among the 4 tested frequencies (500Hz, 1kHz, 2kHz and 4kHz). The contralateral amplitude to the sound stimulation was greater than the ipsilateral amplitude. Furthermore, the amplitude for an upward-gazing position was greater than that for a downward-gazing position. The characteristics of these potentials were similar to those of OVEMP in humans, suggesting that the sound-evoked myogenic potentials around the eyes in monkeys may be utilized as an animal model of OVEMP.