Using intracellular staining with horseradish peroxidase (HRP), Sato et al. (1989) demonstrated the course and termination in the vestibular nuclei of electrophysiologically identified single axons originating from the three semicircular canals. All semicircular canal-activated afferents terminated on all vestibular nuclei. The morphology of physiologically identified otolith-activated afferents (Imagawa et al. 1995, 1998) and 2nd order vestibular neurons (Meng et al. 2002) was investigated by similar methodology with HRP. The ascending branches of otolith axons give off collaterals with boutons in the caudal part of the superior nucleus. The descending branches coursed caudally through the lateral part of the descending nucleus, and gave off collaterals with boutons in the lateral, descending and medial vestibular nuclei. In summary, our data now complete the catalogue of the morphology of individual primary neurons innervating vestibular end organs, i.e. the three canals and the two otolith orngas. As a whole, canal and otolith afferents basically project to the same vestibular nuclei, although there are noticeable quantitative differences. Otolith projections to areas outside the vestibu-lar nuclei where ipsilateral abducens nucleus and reticular formation are present are quite different (Uchino et al. 1994, 1996). The morphology of vestibular neurons was studied by similar methodology with HRP (See Wilson and Melvill Jones 1979). The otolith-activated 2nd order vestibular neurons were pyramidal, elongated and ovoidal in shape. Most of the labeled cells were medium to large. There was no apparent correlation between morphology and the different types of otolith- and canal-activated vestibular neurons. Thus, it seems likely that the functional type of vestibular neurons cannot be presumed on the basis of their morphology alone.
A demographic study of vertiginous elderly patients was performed. Nine hundred and eighty-four elderly patients over 65-years-old (male 373, female 611) who vis-ited the vertigo clinic in Jichi Medical School Hospital from 1993 to 2003 were studied retrospectively, and were compared with 3546 (male 1512, female 2004) patients less than 65-years-old during the same period. The ratio of elderly patients increased gradually, and reached about 30%. Among them, those in their seventies increased remarkably. The male-to-female ratio was 1 : 1.6. Peripheral vestibular disorders and central disorders accounted for 60.7% and 18.9%, respectively. Compared with patients less than 65 years, the former number was almost the same, while the latter one was approximately doubled. In peripheral vestibular disorders, elderly patients had significantly more benign paroxysmal positional vertigo (BPPV) while the ratios of patients with Meniere's disease and vestibular neuronitis were the same as those of the younger group. In central disorders, elderly patients had more cerebro-vascular disorders. The ratio of peripheral vestibular disorders without definite diagnosis increased every year.
Three rare cases are presented that showed a peculiar set of eye movement disorders in the course of Fisher's syndrome, that is, eye movements similar to internuclear ophthalmoplegia, but with restriction of abduction instead of adduction. Characteristics of the abnormal eye movements are summarized as 1) bilateral restriction of the abduction range, 2) bilateral slowing of adducting saccades, and 3) dissociated nystagmus and/or overshooting of the abducting eyes. The possible mechanisms causing these disorders are discussed, and two hypotheses are proposed: 1) possible impairment of inhibition to the medial rectus and 2) independent peripheral control of phasic and tonic eye movements. The latter explanation, primarily assuming peripheral disorders, was considered more suitable.
Hearing loss is the most representative symptom associated with retinitis pigmentosa (RP). But the rate of balance disorder (vertigo or dizziness) has never been reported in Japan. The prevalence of balance disorder and cochlear symptom (hearing loss and tinnitus) were evaluated by questionnaire in subjects who were registered members of the Japanese Retinitis Pigmentosa Society (n=3200) in the year 2002. 834 questionnaires were returned (26.1% response rate), and 828 subjects (25.9%) who had been diagnosed with RP by an ophthalmologist were included in the analysis. The prevalence of balance disorder and cochlear symptoms was 40.5% (n=335). Of 335 subjects with balance disorder, frequency of cochlear symptom and balance disorder only were 57% and 43%, respectively. Of 356 subjects with cochlear symptoms, balance disorder occurred in 56.5%. The prevalence of balance disorder in RP population was high and it was observed at all ages at onset of cochlear symptom and visual loss. We speculate that balance disorder with RP may be caused by vestibular dysfunction, visual dysfunction, and central brain disorder. In order to achieve accurate diagnosis of this disease, studies must be performed by cooperation between otologists and opthalmologists.
The State-Trait Anxiety Inventory (STAI) test is a self survey method used to study a patient's anxiety status. In this study, we investigated the role of dizzy patients' anxiety psychology by analyzing the STAI. Subjects were 377 patients (141 male and 236 female) who complained of dizziness and visited the Department of Otorhinolaryngology at Kansai Medical University from August 2002 to July 2003. 1, In the dizzy patients, State Anxiety (A-State) and Trait Anxiety (A-Trait) score showed significantly higher than in the controls. STAI score in female patients was significantly higher than that in male patients. 2, In the same patients, A-State scores were decreased after patients showed improvement in their symptoms, however A-Trait score were not changed. 3, The patients whose A-State and A-Trait scores in the first medical examination were very high(V) showed high A-State score even after absence of vertigo and dizziness. Based on these results, we concluded that STAI test was simple to use and might provide some helpful information for therapy of anxiety in dizzy patients.
Bow hunter's stroke is vertebrobasilar insufficiency caused by stenosis of vertebral artery (VA) at the atlantoaxial level by head rotation. A 52-year-old man complained of dizziness during head rotation towards the right. Downbeat nystagmus was noted when his neck was rotated to the right. MRI demonstrated hypoplasia of the right VA. Angiography revealed the right hypoplastic VA ending at the posterior inferior cerebellar artery. The left VA was dominant and had normal flow with the head in the neutral position. Head turning to the right caused complete occlusion of the right VA at the level of the atlas and the patient felt dizziness. Surgical therapy was not performed because he did not agree to the operation.
The increasing volume and complexity of medical education have become more apparent recently. An innovative unified curriculum is needed to reinforce the traditional curriculum. Aichi Medical University has decided to employ an integrated curriculum in 2005. We previously introduced a preliminary integrated curriculum starting in 2002 as a collaborative project between the Departments of Anatomy and Otolaryngology. Using the caloric test, a 180-minute unified lesson was employed for second year medical students. As a result, 90% of the students expressed interest in the integrated curriculum compared to 20% of the students expressing interest in didactic lectures. Although an integrated curriculum seemed to be useful, many problems remain to be resolved, such as how to allocate otolaryngology to the proper basic science divisions. We believe that it is crucial to keep pursuing and refining the unified curriculum in order to achieve an ideal medical education.