Tatsuhiko Harada

Efficacy of a vibrotactile neurofeedback training in stance and gait conditions for the treatment of balance deficits: a double-blind, placebo-controlled multicenter study.

Objective Vestibular rehabilitation strategies mostly require a long-lasting training in stance conditions, which is finally not always successful. The individualized training in everyday-life conditions with an intuitive tactile neurofeedback stimulus seems to be a more promising approach. Hence, the present study was aimed at investigating the efficacy of a new vibrotactile neurofeedback system for vestibular rehabilitation. Study Design Double-blinded trial. Patients One hundred five patients who experience one of the following balance disorders for more than 12 months were included in the study: canal paresis, otolith disorder, removal of an acoustic neuroma, microvascular compression syndrome, Parkinson’s disease, and presbyvertigo. Interventions Vibrotactile neurofeedback training was performed daily (15 min) over 2 weeks with the Vertiguard system in those 6 tasks of the Standard Balance Deficit Test with the most prominent deviations from the normative values. Main Outcome Measures Trunk and ankle sway, dizziness handicap inventory, and vestibular symptom score were measured in the verum and placebo group before the training, on the last training day and 3 months later. Results A significant reduction in trunk and ankle sway as well as in the subjective symptom scores were observed in the verum group. Such an effect could not be found in any of the outcome parameters of the placebo group. Conclusion The vibrotactile neurofeedback training applied in the present study is a highly efficient method for the reduction of body sway in different balance disorders. Because the rehabilitation program is easy to perform, not exhausting, and time saving, elderly patients and those with serious, long-lasting balance problems also can participate successfully.

Recurrent extrusion of cochlear implant at an interval of 5 years.

Objective To describe two different types of device extrusion occurring in the same patient 1 and 6 years after cochlear implantation and to discuss the relation between the two extrusions and problems of cochlear implantation in patients with chronic suppurative otitis media. Study Design Retrospective case review. Setting Tertiary referral center. Patient and Interventions The patient was a 52-year-old man with profound hearing loss in the right ear caused by chronic otitis media and deafness in the left ear caused by removal of an acoustic neuroma. Surgery for cleaning the tympanic cavity and reconstruction of the bony canal after previous radical mastoidectomy was performed in the right ear first. One year later, cochlear implantation was performed in this ear. Results One year after implantation, the anterior edge of the internal device of cochlear implant was exposed along the skin incision. This site was stable after corrective surgery. Five years after this operation, however, the posterior edge of the internal device extruded, accompanied by infection around the device. Conclusion The two extrusions occurred with a long interval in between and at two different sites. The first extrusion occurred along the skin incision, and the second extrusion occurred away from the skin incision with infection around the device. The authors assumed that the first and the second extrusion occurred independently; the first extrusion was caused by insufficient blood supply resulting from scar formation from repeated mastoid operations and by pressure on the skin from the internal and external devices, and the second extrusion was caused by proliferated tissue pushing the device upward and against the skin as a result of chronic middle ear infection. The clinical course indicates that sufficiently long follow-up periods are needed to determine the usefulness of the prevention techniques for cochlear implantation in patients with chronic suppurative otitis media.

Eccrine Poroma in the External Auditory Canal

Eccrine poroma is a benign neoplasm of sweat gland origin composed of cells similar to those of the intraepidermal eccrine duct.1 This tumor had once been thought to arise in bare skin of the palms and the soles,2 but more recently it has become clear that this tumor can arise on various hairy skin regions.1 We encountered a patient with an eccrine poroma in the external auditory canal, a site not previously reported.

Physical and physiological effects on otoacoustic emissions in hypobaric hypoxia.

Tinnitus and dizziness are symptoms of acute mountain sickness. We investigated the mechanism by which high altitude (i.e. hypobaric hypoxia) affects inner ear function by measuring transient evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) under conditions of normobaric normoxia (1,013 hPa; 760 mm Hg) and hypobaric hypoxia (540 hPa; 405 mm Hg). The possibility that air pressure effects on the eustachian tube impacted our findings was excluded by the use of tympanograms. The nonphysiological effects of hypobaric hypoxia on TEOAE and DPOAE were also assessed using an ear simulator. Under conditions of hypobaric hypoxia, both TEOAE and DPOAE levels were reduced. The amount of reduction that occurred was approximately 4 dB in the total echo power and signal-to-noise ratio of the TEOAE, and in the 2f1 – f2 element level of the DPOAE. Stimulus levels that were measured using an ear simulator were also reduced by approximately 4 dB under conditions of hypobaric hypoxia. These results do not indicate that stimulus levels affected TEOAE and DPOAE levels because these levels were actually only slightly affected by changes in the stimulus level. Instead, this reduction was likely due to the nonphysiological hypobaric effects of the sound pressure emitted from the tympanic membrane. We conclude that the impact of hypobaric hypoxia on cochlear function was negligible up to pressures of 540 hPa.

Mechanisms of photoinduced cochlear ischemia in the guinea pig.

An experimental model of cochlear ischemia using the photosensitization reaction of rose bengal (RB) is reported. Ischemia was induced by the systemic administration of RB solution and localized irradiation of the cochlea with a green light of specific wavelength for RB activation. After the RB solution was administered, the cochlear blood flow was temporarily increased and then decreased, and the latency of wave I of the auditory brainstem response increased and the amplitude of wave I decreased after RB injection and finally wave I disappeared completely. A histological study revealed thrombus formation in the vessels of the irradiated cochlea not only in the stria vascularis and the spiral ligament, but also in the modiolus. L-Histidine, a scavenger of singlet oxygen (1O2) and hydroxyl radical (·OH), significantly prolonged cochlear dysfunction, but D-mannitol, a specific scavenger of ·OH did not, suggesting that 1O2 has an important role in this reaction.