Reversal of paradoxical stimulation (false inversion) in perforated tympanic membranes by increasing the time of warm stimulation, evidenced by a physical model.

OBJECTIVE: To measure the time required in patients with tympanic perforation to reverse paradoxical stimulation (reverse pseudo-nystagmus) and to create a physical model of the process. METHOD: An analytical, observational, cross-sectional study with vestibular evaluation (electronystagmography) of 52 individuals with tympanic membrane perforation without otorrhea or concomitant disease. Increased duration of caloric stimulation in the presence of paradoxical stimulation (reverse pseudo-nystagmus) reverses nystagmic responses. RESULTS: Reversal of nystagmus was observed in 90.9% of patients. The average reversal time was 105.5 seconds. The physical model we prepared provided supporting evidenced for the effects seen in these individuals: warm stimulation in a moist environment initially caused a decrease in temperature (nystagmus to the unexpected side, which characterizes paradoxical stimulation in the warm caloric test); but, as time passed by, the moisture evaporated, and the temperature gradually increased (reversal of nystagmus). CONCLUSIONS: Increasing the stimulation time can be used as a strategy to differentiate reverse nystagmus from paradoxical stimulation. Confusion is thus avoided in diagnostic findings, allowing peripheral alterations to be distinguished from central ones.

Suspensory Tethers and Critical Point Membrane Displacement in Endolymphatic Hydrops

Abstract Introduction Grossly displaced membranes are characteristic of endolymphatic hydrops. The process whereby physiological membrane displacement becomes pathological may be mediated by stress, but the membrane biomechanics underlying this transition are unclear. Objective This study seeks to determine the role of suspensory tethers during pressure-induced membrane displacement in the generation of the membranous lesions seen in this disease entity using a biomechanical model approach. Methods The location of membrane suspensory tethers was identified histologically. The influence of tethers on model membrane configuration during displacement was assessed graphically. The relationship of membrane configuration during displacement to curvature radius was quantified trigonometrically. The relationship of curvature radius to stress susceptibility was determined mathematically. The net effect of suspensory tethers on membrane stress levels for various degrees of membrane distention and displacement was then calculated numerically. Results In the inferior labyrinth, suspensory tethers are found to occur on the membranes' boundaries. Such tethering is found to impose a biphasic effect on membrane curvature with increasing degrees of displacement. As a consequence, tensile stress susceptibility is found to decline with initial membrane displacement to a critical point nadir beyond which stress then increases monotonically. No such effect was found for the superior labyrinth. Conclusion Boundary tethers in the inferior labyrinth are associated with significant tensile stress reductions until a critical point of membrane displacement is reached. Displacements short of the critical pointmay be physiological and even reversible,whereas such displacements beyond the critical point are apt to be overtly hydropic and irreversible.

Correlation between sensorineural hearing loss and chronic otorrhea.

Many studies have attempted to correlate chronic otorrhea in children and in adults with the sensorineural hearing loss in the affected ear, with contradictory results. This loss might be the result of the likely toxicity of the bacteria involved, effects of inflammatory cytokines, or constant use of ototoxic antibiotics. All studies evaluated to date compared the affected ear with the normal contralateral ear. From the digitized archive of otologic surgery files of the Department of Otorhinolaryngology at Santa Casa de São Paulo School of Medical Sciences, the ears of patients with chronic otorrhea were evaluated visually and compared with the normal contralateral ears. Ears with otorrhea were also compared with ears of other patients with dry tympanic perforation. Ears with suppuration were evaluated for cholesteatoma. The duration of otorrhea was considered. The sensorineural hearing threshold was evaluated for the frequencies of 500, 1,000, 2,000, and 4,000 Hz. A total of 98 patients with chronic otorrhea and 60 with dry tympanic membrane perforation were evaluated. A correlation between sensorineural hearing loss and chronic otorrhea was observed when compared with both contralateral normal ears and dry perforated ears of other patients. No relationship between hearing loss and the duration of suppuration or cholesteatoma was found. Sensorineural hearing loss occurs in ears with chronic otorrhea. The duration of otorrhea and the etiology of suppuration did not influence the hearing loss.

Air stimulation in tympanic perforation: inverted nystagmus study.

UNLABELLED: Response inversion during warm air stimulation is the most controversial finding seen in caloric tests of individuals with tympanic membrane perforation. In such cases, very few studies explore the possible interferences found in the caloric test, bringing about controversies in the interpretation of test results. AIM: This paper aimed at analyzing warm air stimulation effects in individuals with tympanic membrane perforation in comparison with normal healthy controls. MATERIALS AND METHODS: Prospective, non-randomized study in which 48 individuals without vestibular complaints were assessed, 33 had one tympanic membrane perforated and 15 had no ear drum alteration. RESULTS: 39.39% of the individuals had response inversion found during the warm air test. In the absence of this phenomenon, nystagmus responses were symmetrical. CONCLUSION: Nystagmus responses to the caloric test in individuals with tympanic membrane perforation were similar to those from healthy controls, with the exception of the fact that they had inverted responses in the warm caloric test.

A computational method for the semi-automated quantitative analysis of tympanic membrane perforations and tympanosclerosis.

Tympanic membrane pathological findings such as perforations and tympanosclerotic plaques (along with conductive hearing loss and purulent drainage) are the most typical trademarks of either active or burned-out chronic otitis media. These findings are normally evaluated by an expert using visual subjective analysis. In this work, we present a computational semi-automated method to quantify these pathologies. We also present a validation study of the method using a subset of 39 cases randomly extracted from a set of more than 2000 cases (perforations and tympanosclerosis) of the Hospital de Clínicas de Porto Alegre. The validation was performed using Ground Truth images, generated by experts, and has shown promising results.

Air stimulation in tympanic perforation: inverted nystagmus study / Estimulação a ar na perfuração timpânica: estudo da inversão nistágmica

Response inversion during warm air stimulation is the most controversial finding seen in caloric tests of individuals with tympanic membrane perforation. In such cases, very few studies explore the possible interferences found in the caloric test, bringing about controversies in the interpretation of test results. AIM: This paper aimed at analyzing warm air stimulation effects in individuals with tympanic membrane perforation in comparison with normal healthy controls. MATERIALS AND METHODS: Prospective, non-randomized study in which 48 individuals without vestibular complaints were assessed, 33 had one tympanic membrane perforated and 15 had no ear drum alteration. RESULTS: 39.39 percent of the individuals had response inversion found during the warm air test. In the absence of this phenomenon, nystagmus responses were symmetrical. CONCLUSION: Nystagmus responses to the caloric test in individuals with tympanic membrane perforation were similar to those from healthy controls, with the exception of the fact that they had inverted responses in the warm caloric test.

A inversão de respostas durante a estimulação a ar quente é o achado mais controverso que aparece na prova calórica de indivíduos com perfuração da membrana timpânica. Nestes casos, poucos estudos exploraram as possíveis interferências nos achados da prova calórica, trazendo controvérsias de interpretação no resultado do exame. OBJETIVO: Este trabalho teve o objetivo de analisar a estimulação calórica a ar em indivíduos com perfuração da membrana timpânica em comparação com indivíduos hígidos, sem esta alteração. MATERIAL E MÉTODO: Estudo prospectivo, não-randomizado, no qual foram avaliados 48 indivíduos sem queixas vestibulares, sendo 33 indivíduos com membrana timpânica perfurada unilateralmente e 15 indivíduos sem nenhuma alteração na membrana timpânica. RESULTADOS: 39,39 por cento dos indivíduos apresentaram inversão de respostas na prova calórica a ar quente. Na ausência deste fenômeno as respostas das nistágmicas foram simétricas. CONCLUSÃO: As respostas nistágmicas na prova calórica em indivíduos com perfuração da membrana timpânica foram similares aos indivíduos hígidos, com exceção da presença de inversão de respostas na prova calórica quente.