Orthostatic hemodynamics in the vertebral artery and blood pressure in patients with orthostatic dizziness/vertigo.

OBJECTIVES: Orthostatic dizziness/vertigo (ODV) is a common symptom and is believed to occur due to the cerebral hypoperfusion caused by orthostatic hypotension (OH). However, the detailed mechanism underlying ODV onset is poorly understood. The vertebral artery (VA) mainly supplies blood to the central vestibular system; therefore, the orthostatic decrease of VA blood flow could possibly lead to ODV. This study investigated the orthostatic blood pressure and VA hemodynamics in ODV patients to elucidate the hemodynamic mechanism underlying ODV onset. Furthermore, the influence of orthostatic hypotension (OH) on VA hemodynamics was examined because OH is probably the most common cause of ODV. METHODS: This study included 181 patients with ODV and 73 control patients without ODV. All subjects underwent an active standing test to measure the extracranial Doppler (ECD) sonography spectrum of the VA and blood pressure (BP). VA blood flow velocity and BP were simultaneously measured for each patient in the supine static position and then in the upright standing positions following 3 min of standing. We investigated the orthostatic change in the average of flow velocity in bilateral VAs (VAFV) and BP for ODV patients compared with the control patients. RESULT: VAFV in ODV patients was significantly reduced when standing up compared with the control patients. In the ODV patients, there was no difference in orthostatic decrease in VAFV between patients those with OH and without OH. However, the VAFV in the standing position was significantly lower in patients with OH than without OH. In cases with OH, the ODV patients exhibited a greater decrease in VAFV compared with the control patients, but this was not statistically significant. In the absence of OH, a significantly greater orthostatic decrease in VAFV was observed in ODV patients compared with the controls. CONCLUSION: Our findings suggest that the orthostatic decrease of VA blood flow is deeply involved in the hemodynamic mechanism underlying ODV onset and is possibly associated with OH and other etiologies.

Long-term effects of electrotactile sensory substitution therapy on balance disorders.

This clinical research investigated whether a new type of rehabilitation therapy involving the use of a vestibular substitution tongue device (VSTD) is effective for severe balance disorders caused by unilateral vestibular loss. Sixteen patients with postural imbalances because of unilateral vestibular loss underwent training with VSTD. The VSTD transmits information on the head position to the brain through the tongue as substitutes for the lost vestibular information. The device's electrode array was placed on the tongue and participants were trained to maintain a centered body position by ensuring the electrical signals in the center of their tongue. All participants completed 10 min training sessions 2-3 times per day for 8 weeks. Functional gait assessments and the dizziness handicap inventory were, respectively, used to the evaluate participants' dynamic gait function and their severity of balance problems before and after the training period. All examined parameters improved after the 8-week training period. These changes were maintained for up to 2 years after the termination of the training program. Short-term training with VSTD had beneficial carry-over effects. VSTD training might represent a useful rehabilitation therapy in individuals with persistent balance disorders and might lead to long-term improvements in their balance performance and ability to perform daily and social activities.

[COMPARISON BETWEEN QFT-3G AND T-SPOT IN THE CONTACT INVESTIGATION OF A TUBERCULOSIS OUTBREAK].

PURPOSE: We experienced a tuberculosis outbreak in a business establishment. Contact investigation was carried out using both the QFT-3G and T-SPOT tuberculosis (TB) tests on the same subjects and the test results were compared. METHOD: The QFT-3G and T-SPOT tests were performed simultaneously at three time points during the contact inves- tigation, so just after tuberculosis registration (n =14), at 3 months post registration (n=24), and at 2 years post regis- tration (n=22). Chest radiography was also performed for all subjects (n = 3 1) just after the registration. RESULTS: From the contact investigation results, 2 cases of pulmonary tuberculosis and 14 of latent tuberculosis infection (LTBI) were detected. It was considered that the TB infection rate was high in the investigated group. The QFT-3G and T-SPOT positive rates, respectively, were 71 % (10/14) and 29% (4/14) just after registration, 38% (9/24) and 4% (1/24) at 3 months post registration, and 27% (6/22) and 5% (1/22) at 2 years post registration, and deviated from each other significantly (concordance rate, Ic 0.16 - 0.27). The positive rate of QFT-3G was significantly higher than that of T-SPOT, and QFT-3G could detect TB infection earlier than T-SPOT. The differences of test characteristics had no little impact on the diagnostic rate of LTBI. DISCUSSION: It is important that the diagnosis and treat- ment of LTBI be evaluated in a comprehensive manner, after considering test characteristics of the interferon-gamma release assay and epidemiological information of TB.

Regeneration of the nerves in the aerial cavity with an artificial nerve conduit --reconstruction of chorda tympani nerve gaps-.

OBJECTIVES/HYPOTHESIS: Due to its anatomical features, the chorda tympani nerve (CTN) is sometimes sacrificed during middle ear surgery, resulting in taste dysfunction. We examined the effect of placing an artificial nerve conduit, a polyglycolic acid (PGA)-collagen tube, across the gap in the section of the resected chorda tympani nerve (CTN) running through the tympanic cavity. METHODS: The CTN was reconstructed with a PGA-collagen tube in three patients with taste disturbance who underwent CTN resection. To evaluate the effect of the reconstruction procedure on the patients' gustatory function, we measured the patients' electrogustometry (EGM) thresholds. The patients were followed-up for at least two years. RESULTS: Gustatory function was completely restored in all of the patients after the reconstruction. The patients' EGM thresholds exhibited early improvements within one to two weeks and had returned to their normal ranges within three months. They subsequently remained stable throughout the two-year follow-up period. In a patient who underwent a second surgical procedure, it was found that the PGA-collagen tube used in the first surgical procedure had been absorbed and replaced by new CTN fibers with blood vessels on their surfaces. CONCLUSION: These results suggest that reconstruction of the CTN with an artificial nerve conduit, a PGA-collagen tube, allows functional and morphological regeneration of the nerve and facilitates the recovery of taste function. PGA-collagen tubes might be useful for repairing CTNs that are resected during middle ear surgery. Further research is required to confirm these preliminary results although this is the first report to describe the successful regeneration of a nerve running through an aerial space.

The effect of prostaglandin E1 on brainstem blood flow disturbance in an animal model of vertebrobasilar insufficiency.

Using an animal model of vertebrobasilar insufficiency (VBI), in which brainstem circulatory disturbance was induced in rats, we examined how prostaglandin E1 (PG-E1) affects brainstem blood flow (BBF) to clarify whether it is effective against VBI. Fifteen healthy male Wister rats that displayed positive responses to Preyer's reflex were used. Their BBF was continuously measured on the left side of the midline of the brainstem using laser Doppler flowmetry. A rat model of VBI, a pathological condition that presents with decreased BBF, was prepared by applying a vertebral artery clamp ipsilateral to the BBF measuring site and inducing hypotension of 60-70 mmHg by blood withdrawal. Saline as a control (n = 5), 5 ng/kg/min (n = 5) or 10 ng/kg/min (n = 5) PG-E1 at a dose was continuously administered to the rats using a motor-driven syringe pump. The effects of the drugs on the rats' BBF were evaluated. BBF, which was decreased by the unilateral vertebral artery clamping combined with blood withdrawal-induced hypotension, recovered in a dose-dependent manner after the administration of 5 or 10 ng/kg/min PG-E1, and complete recovery to the baseline level was achieved by 60 min treatment; however, no such effect was observed for intravenous saline. These results suggest that PG-E1 acts on local vessels and improves blood flow insufficiency in the brainstem in our animal model of VBI. PG-E1 might be useful as a cerebral vasodilator for VBI.

New treatment strategy for cupulolithiasis associated with benign paroxysmal positional vertigo of the lateral canal: the head-tilt hopping exercise.

This study was performed to determine whether a novel treatment was effective against cupulolithiasis associated with benign paroxysmal positional vertigo (BPPV) of the lateral semicircular canal, which is characterized by apogeotropic direction-changing nystagmus. We herein describe our head-tilt hopping (HtH) exercise, which is designed to release otoconial debris strongly adhered to the cupula. The subjects were trained to hop while tilting their heads laterally. They completed 3 to 5 exercise sessions per day over a 4-week period. Each session ended with a 20-hop trial. The HtH exercises were performed by 27 patients with intractable lateral canal BPPV who exhibited positional vertigo and persistent nystagmus beating toward the uppermost ear for more than 4 weeks, despite performing therapeutic head shaking in the horizontal plane maneuver. All the patients were subjected to the supine roll test before and immediately after the first trial as well as after 1 and 4 weeks of the program to evaluate the effect of the treatment on their apogeotropic nystagmus. Nystagmus of 9 (33.3 %) patients disappeared immediately after the first training session. After 1 and 4 weeks of the training, the number of patients that had experienced either of these improvements had increased to 15 (55.6 %) and 19 (70.4 %) subjects, respectively. These results suggest that HtH exercises aimed at releasing otoconial debris from the cupula are feasible as a new therapy for cupulolithiasis associated with intractable lateral canal BPPV. However, further studies for comparison with control are required to confirm these preliminary results.

The prevalence and characteristics of metabolic syndrome in patients with vertigo.

OBJECTIVES/HYPOTHESIS: Metabolic syndrome (MetS) is a condition that increases the risk of coronary artery disease and cerebral infarction. We determined the prevalence of MetS in vertigo patients and clinically investigated the association between MetS and vertigo. STUDY DESIGN: Case-control study. METHODS: The subjects were 333 patients, including 107 males and 226 females, who presented with vertigo as a primary symptom. MetS was diagnosed according to the International Diabetes Federation definition, which is based on waist circumference, blood serum levels, and blood pressure. RESULTS: MetS was detected in 53 (15.9%) of 333 vertigo patients, including 24 males (22.4%) and 29 females (12.8%); i.e., the frequency of MetS was significantly higher among the male patients than the female patients. The overall prevalence of MetS (15.9%) among vertigo patients did not differ from that observed among general adults in previous Japanese surveillance studies; however, MetS was significantly more common among the vertigo patients in males than general adult males. The prevalence of MetS was also examined in five types of vertigo, Concomitant MetS was noted in many males with vertebrobasilar insufficiency (VBI) and isolated vertigo of unknown etiology. CONCLUSION: It was suggested that MetS is involved in the development of vertigo in males. MetS might be a risk factor for vascular vertigo such as VBI in males. The high frequency of MetS among males with vertigo of unknown etiology suggested that the pathogenesis of metabolic syndrome is involved in this type of isolated vertigo.

Osteoporosis as a risk factor for the recurrence of benign paroxysmal positional vertigo.

OBJECTIVES/HYPOTHESIS: Benign paroxysmal positional vertigo (BPPV) frequently occurs in females over 50 years old, suggesting that a postmenopausal decrease in estrogen secretion might be involved in its onset. An estrogen deficiency is generally known to cause osteoporosis through a reduction in bone mass. This study was designed to investigate a clinical association between idiopathic BPPV and osteoporosis. STUDY DESIGN: Case-control study. METHODS: We measured the bone mineral density (BMD) at the lumbar vertebrae in 61 patients with idiopathic BPPV who were postmenopausal women over 50 years old using dual-energy x-ray absorptiometry. After being treated with the canalith repositioning maneuver, the patients were followed up for at least 1 year. RESULTS: Our results showed that the incidence of osteoporosis in patients with BPPV was 26.2%, which was similar to those observed in epidemiological surveys conducted in Japan. However, we found that in BPPV patients with osteoporosis, the incidence of recurrence was 56.3%, which was significantly higher than that observed in patients with normal bone mineral density (16.1%). Furthermore, the frequency of BPPV recurrence increased as BMD decreased. CONCLUSIONS: These results suggest that osteoporosis is a risk factor for BPPV recurrence. The prognosis of BPPV might be clinically predicted by BMD reduction.

[Clinical analysis of metabolic syndrome in vertiginous diseases].

To explore the relationship between metabolic syndrome and vertigo, we measured waist circumference, plasma glucose, triglycerides and blood pressure in 333 subjects aged 20-79 years with vertigo. We found overall metabolic syndrome prevalence defined by Japanese diagnostic criteria to be 13.2%, similar to that in other national surveys by the Japanese Ministry of Health, Labour and Welfare. The 6-fold higher prevalence in men over women exceeded that of other reports, however. The highest frequency was in vertebrobasilar insufficiency (VBI) disorders, suggesting that conditions such as VBI in men with vertigo could involve metabolic syndrome as a risk factor for vertigo incidence.