In humans, intense sound evokes ipsilateral myogenic potentials in the sternocleidomastoid muscle (SCM) with a short latency positive-negative (p13-n23) waveform. This sound-evoked vestibulocollic reflex is termed the vestibular-evoked myogenic potential (VEMP). In the present study, the technical and diagnostic pitfalls of the VEMP are introduced. An electromyograph (EMG) is used to record signals from a pair of surface electrodes mounted on the upper-half (active electrode) and the sternal head (reference electrode) of the SCM. The positions of the electrodes influence the p13-n23 amplitude and the VEMP waveform. Head rotation around the yaw axis brings the proximal end of the unilateral SCM muscle close to the distal end, making the outline of the SCM muscle more visible on the body surface. This rotation is useful for the precise positioning of the electrodes. The muscle background activity during the test influences the p13-n23 amplitude of the VEMP. Subjects are instructed to rotate their heads around the yaw axis contralateral to the sound stimulation so as to contract their unilateral SCM muscles. During the VEMP test, the background EMG activity of the tested SCM is continuously monitored, and the peak-to-peak amplitude in the interference pattern of the background EMG should be maintained at more than 200 μV. When the attenuation of the amplitude in the interference pattern begins, the subjects should be instructed to rotate their heads once again so as to recover tonic contraction. The muscle background activity during the test is electromyographically estimated based on the integral value of the rectified EMG activity level for 20 milliseconds preceding the stimulus onset. When the integral value of the rectified EMG activity is less than 1000 μV×ms, the background EMG activity of the tested SCM is objectively evaluated as being too low to induce the evoked response. To correct the amplitude according to the muscle background activity, the p13-n23 amplitude is divided by the integral value of the rectified EMG activity level. This correction is important for the test-retest reproductivity of the VEMP amplitude. To diagnose a right-left asymmetry in the VEMP amplitude, the clinical use of the corrected amplitude is recommended.
To investigate how mimetic words are related to conventional medical terms, types of diseases, and the severity of symptoms, 40 consecutive patients with dizziness symptoms were interviewed and asked to describe their dizziness. Mimetic words were recorded from each patient, while conventional medical terms used to describe their symptoms, clinical diagnosis, and subjective symptom severity were also noted. Thirty-five of the 40 patients spontaneously used mimetic words. Although no significant relationships were observed between mimetic words and disease groups, consistencies between the word “guru” and rotatory vertigo and between the word “huwa” and disequilibrium were suggested. The severity of the symptoms was correlated with the specific word that the patients use. Particularly, “guru” was never used by patients who rated their symptoms as mild. Overall, 130 of the 134 syllables that were collected had either an /a/ or an /u/ vowel sound, whereas an /e/ vowel sound never appeared. Sixty of the 71 first syllables contained one of the three consonants /g/, /h/, or /k/. In the severe-symptom group, the first consonant that appeared most frequently was /g/, while the second vowel was more often /u/ than /a/. Clinicians may need to be aware of the properties of sound symbolism, an essential linguistic method for Japanese-speaking patients to describe dizziness.
The purpose of this study was to confirm the effect of herbal tea therapy on Ménière's disease. We studied nine patients with Ménière's disease who visited the International University of Health and Welfare MITA hospital in 2008. According to criteria of the Japan Society for Equilibrium Research, all the patients were diagnosed as having Ménière's disease or cochlear Ménière's disease and underwent audiometric measurements and questionnaires regarding their functional level and tinnitus symptoms every month. Moreover, we instructed these patients to keep a record of the number of times they experienced vertigo. After 6 months of general treatment, we treated the patients with an herbal tea for one year. To minimize adverse effects, we used a blend of herbal teas. This herbal tea was effective as a diuretic, for alleviating vertigo, and for promoting relaxation. We compared the patients' symptoms before and after the herbal tea therapy. Herbal tea therapy was effective for all the patients, and none of the patients experienced a relapse or adverse effects. Thus, the herbal tea therapy improved their Ménière's symptoms. Our study provides evidence that herbal tea therapy is useful for preventing the worsening of Ménière's disease.
In a regional central hospital, the number of hospital inpatients with vertigo decreased along with a decrease in full-time doctors in the Department of Otorhinolaryngology and a decrease in the number of hospital beds. The reason for this trend is that emergent and surgical diseases requiring hospital treatment were given priority; for patients with vertigo disorders, admission was adjusted so as to focus on patients with objective findings (such as cranial nerve and auditory disorder findings). The number of patients with vertigo who are hospitalized in our department has decreased; however, this trend has had a minimal effect on other departments. The number of cases requiring hospitalization as a result of vertigo can be limited, and treatment can be provided on an outpatient basis. When limiting hospitalization, the differentiation of central nervous system disorders is important. Based on the characteristics of vertigo, the condition tends to be treated on an outpatient basis in many cases. Hence, attention should be paid to reducing the dependency on physicians on duty (such as physicians from other departments who provide medical treatment to patients at the time of their initial visit), to differentiating central nervous system disorders, and to explaining the initial treatments to patients with vertigo and their family members.
A 27-year-old woman who was referred to our hospital 5 days after an episode of vertigo had experienced right facial palsy 2 days earlier and a feeling of numbness in her left hand one year earlier. Ocular movement showed rotatory nystagmus in the positioning nystagmus, and the abduction of the right eye was impaired. A T2-weighted magnetic resonance imaging (MRI) study showed multiple high-intensity lesions in the dorsal pons and white matter close to the lateral ventricles, supporting a diagnosis of multiple sclerosis. Methylprednisolone pulse therapy effectively alleviated the patient's complaints except for the feeling of numbness in the left hand, and the patient's ocular movements normalized within one month. A neuro-otology examination, such as the observation of eye movements, is a key study for suspected brain lesion symptoms.
We report a patient with mumps meningitis and MERS (clinically mild encephalitis/encephalopathy with reversible splenial lesion) who exhibited flutter-like oscillations. A 7-year-old boy complaining of a headache, vomiting and dizziness consulted the Department of Pediatrics. Since he was positive for hemolytic streptococcus but did not exhibit cervical rigidity, an antibiotic was prescribed. He was brought back to the Department of Pediatrics after suffering from convulsions two days later. A high-intensity spot was found in the splenium of the corpus callosum on a diffusion-weighted magnetic resonance imaging (MRI) examination. The patient showed irregular horizontal eye movements and was referred to our department under a suspicion of peripheral vertigo. We found a horizontal pendular ocular movement with a small oscillation and a short duration and suspected flutter-like oscillations. No new lesions were found on a subsequent MRI examination, and the symptoms gradually improved without any additional treatment. The patient was discharged 20 days later. The diagnosis was mumps meningitis, acute cerebellar ataxia, and MERS based on a cerebrospinal fluid polymerase chain reaction (PCR) test and the MRI results. The patient's symptoms had disappeared at a follow-up examination performed in the outpatient department 47 days later. Flutter-like oscillations are an irregular ocular movement found in cases with an impaired brainstem or cerebellum. Flutter-like oscillations often occur with changes in fixation and are presumably caused by a malfunction in pause neurons in the brainstem. MERS is characterized by a reversible splenial lesion of high intensity on diffusion-weighted MRI in association with various diseases such as viral infection, epilepsy, renal failure and electrolyte imbalance. The cause is thought to involve inflammatory infiltrates or intramyelinic edema. The present report is thought to be the first description of a case of MERS exhibiting flutter-like oscillations. Since flutter-like oscillations may be confused with peripheral nystagmus, despite the distinctive ocular movement, a neurootologist consultation is desirable, especially in cases where central impairment is suspected.