One of the main reasons for the slow clarification of the mechanisms of inner ear diseases such as Ménière's disease and the establishment of curative treatments, is that there is as yet no procedure that can non-destructively recognize the morphology of the soft tissue of the inner ear, because the spatial resolution of medical imaging equipment such as X-ray CT and MRI is too low to resolve fine structures such as the vestibular membrane, the so-called Reissner's membrane. We have successfully visualized fine structures like Reissner's membrane and the spiral ganglion in the human fetal cochlea for the first time by employing micro-CT with a spatial resolution hundreds or thousands of times greater than that of medical CT. The principle of micro-CT, importance of the visualization of audibility and equilibrium organs, associated problems, points to be made aware of, and prospects of micro-CT are discussed hereinafter.
To investigate the relationship between white matter lesions identified on MRI and balance dysfunction in elderly persons, we evaluated findings on brain MRI and body sway examined with a stabilometer in persons (n=49) aged over 50 years old who were hospitalized for a thorough medical checkup. The total number and major axes of spots indicating deep white matter, hyperintense signals (DWMH) on MRI were measured. If the total number of spots exceeded 10 or the major axes exceeded 4 mm, white matter changes were judged to be severe. Sway of the body is center of gravity was recorded with eyes open and closed for 60 seconds using a stabilometer. The sway area and locus length, as well as left-right (X position) and forward-backward (Y position) deviation of the center of sway were measured. The measurements regarding these parameters were compared with standard values in healthy subjects. Persons with normal values in all 4 parameters (sway area and right-left deviation with eyes open and closed) were regarded as stable, and persons with values beyond the normal range were regarded as unstable. Elderly persons with severe white matter lesions on MRI identified on a thorough medical checkup were significantly unstable. We suggested that elderly persons with severe white matter lesions tended to exhibit postural abnormalities due to brain arteriolosclerosis. Tokita proposed the usefullness of stabilometry on health examination to check the health condition and detect any signs of Cerebrovascular disorders. We believe that our results also showed the utility of stabilometry in health examinations.
Introduction: During the acute phase, patients with vestibular neuritis suffer from severe vertigo. With time, the intensity of vertigo gradually decreases. The aims of the present study were: (1) to determine whether changes in the subjective visual vertical (SVV) system reflect how patients subjectively experience vertigo, and (2) to determine the relationship between changes in SVV and canal paralysis (CP). Methods: Our subjects comprised 23 patients with vestibular neuritis. We measured the SVV of each patient several times to evaluate the recovery of SVV and CP over time. The intensity of vertigo was graded numerically as follows: (1) 5—very intense (patient cannot stand with eyes open), (2) 4—intense (patient cannot stand with eyes closed), (3) 3—moderate (patient can stand with eyes closed), (4) 2—slight vertigo, and (5) 1—no vertigo. We also evaluated CP in 10 patients using the thermal caloric test. Results: The temporal process of SVV recovery was grouped into three categories: (1) small fluctuation/rapid recovery (N=7); (2) small fluctuation/delayed recovery (N=8); and (3) large fluctuation (N=8). For CP recovery, we observed cases that failed to recover (N=4) and others that did recover (N=6). When tested 30 days and 1 year after the initial examination, the CP recovery group displayed larger SVV fluctuations accompanied by intense subjective vertigo, whereas the group that did not recover exhibited fewer fluctuations accompanied by weak vertigo. Conclusions: SVV represents the subjective perception of the direction of gravity. Fluctuations in SVV, rather than absolute SVV, correlate well with the subjective intensity of vertigo. This suggests that, during the recovery process, fluctuations in SVV, rather than the dysfunction itself, causes dizziness. Measuring SVV is very straightforward and quantifying SVV fluctuations is an effective measure of the intensity of vertigo.
Introduction: Dizziness and vertigo are symptoms of various psychiatric conditions like major depression, somatoform disorder, anxiety disorders, and so on. Phobic postural vertigo (PPV) was first reported by Brandt T et al. in 1994. PPV occurs chiefly in patients with an obsessive-compulsive or narcissistic personality. The diagnosis is based on six characteristics proposed by Brandt et al. The key for a correct diagnosis is spontaneous (sometimes stimulus-induced) postural vertigo and unsteadiness in maintaining an upright position and walking. Methods: The characteristics of patients with PPV were reviewed in 16 patients from June 2002 to November 2006 in our hospital. Some psychological evaluations were preformed by a self-rating questionnaire. MAS (Manifest Anxiety Scale) was used to evaluate the level of anxiety, and the Japanese version of MOCI (Maudsley's Obsessional Compulsive Inventory) was employed to evaluate the obsessive-compulsive personality. Results: We encountered 16 PPV patients. Fourteen were female and 2 were male. The average age was 55±15.5 years old. Many of the patients showed depression and a high level of anxiety. The average MOCI score was 10.8, and this indicated an obsessive-compulsive or narcissistic personality. Treatment involved drug therapy with SSRI (Selective serotonin reuptake inhibitors), antidepressants, anxiolytics like benzodiazepine (BZD), and psychotherapy including cognitive behavior therapy and autogenic training. Conclusion: The diagnosis of PPV was important to improve the prognosis. The key for a correct diagnosis is not anxiety but the subjective dizziness itself. An obsessional personality is often observed.
We previously reported that optokinetic stimulation elicited body sway in the same direction as the stimulus flow when a fixation target was present, but in the opposite direction when there was no such target. On the other hand, posterior neck muscle vibration reportedly elicits body sway in the direction of gaze. Optokinetic stimulation without a fixation target could elicit not only optokinetic eye movement, but also static shift of the gaze direction. Our aim was to determine, in the absence of a fixation target, whether the gaze direction or optokinetic eye movement drives the body-sway response. We applied posterior neck muscle vibration and optokinetic stimulation simultaneously, and compared the body-sway to the gaze direction. The direction of the elicited body sway was opposite to the optokinetic flow, and the amplitude of displacement was greater than the shift in the direction of gaze. The body sway didn't demonstrate a time-dependent reduction during optokinetic stimulation. We conclude that optokinetic eye movement drives a dynamic, accumulative mechanism that induces a postural response, which exceeds the shift in the direction of gaze.