L'APPARATO UDITIVO:FISIOLOGIA E PATOLOGIA

Objective: The purpose of this study was to determine the effectiveness of a new physical maneuver in the treatment of the apogeotropic variant of horizontal canal benign paroxysmal positional vertigo. Study Design: Case review. Setting: Outpatient clinic. Patients: The diagnosis of apogeotropic horizontal canal benign paroxysmal positional vertigo was based on the history of recurrent sudden crisis of vertigo associated with bursts of horizontal apogeotropic paroxysmal nystagmus provoked by turning the head from the supine to either lateral position. The patients were three men and five women ranging in age from 31 to 73 years (average, 49.2 yr). Interventions: All patients were treated with a repositioning maneuver based on the hypothesis that the syndrome is caused by the presence of free-floating dense particles inside the endolymph of the anterior arm of the horizontal canal. The maneuver favors their shifting into the posterior arm of the canal. Patients were reexamined immediately after the treatment and underwent Gufoni's liberatory maneuver for the geotropic variant of horizontal canal benign paroxysmal positional vertigo. Main Outcome Measure: The treatment outcome was considered as responsive when, after one repositioning maneuver, nystagmus shifted from apogeotropic to geotropic. Results: The repositioning maneuver resulted in a transformation from the apogeotropic variant into a geotropic variant of horizontal canal benign paroxysmal positional vertigo in all patients. Conclusion: This maneuver represents a simple and effective approach to the treatment of the apogeotropic variant of horizontal canal benign paroxysmal positional vertigo. It favors the shifting of the canaliths from the anterior into the posterior arm of the horizontal canal from where they can migrate into the utricle with Gufoni's maneuver

ACUFENI

per acufene si intende una sensazione sonora percepita dal paziente,non sostenuta da sorgenti esterne, causata da attività proprie dell'apparato acustico o da alterazioni dei meccanismi di elaborazione sensoriale

SOME EFFECTS OF TONAL FATIGUING ON SPONTANEOUS AND DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS

Auditory fatiguing can be considered a suitable test to assess some cochlear mechanisms and diseases otherwise not easily detectable. Since spontaneous otoacoustic emissions (SOAEs) originate from active sources within the cochlea they show sensitive and early vulnerability to noise, displaying informative time-courses after overstimulation in the short (0-6 s) and in the long term (1-10 min) depending on the frequency of the fatiguing stimulus. Distortion product otoacoustic emissions too, in subjects with SOAEs, show interesting modifications after pure-tone exposure, detectable either on distortion product audiograms or in the growth functions. The modifications take place within a period of 5-7 minutes and strongly depend on the frequency of the fatiguing stimulus and on the closeness between SOAE and distortion product place. The data suggest that not only the interaction place between f1 and f2 has to be considered from a biomechanical and clinical point of view, but also the specific distortion product place on the cochlear partition