Electrophysical properties and transfer function of the vestibular labyrinth

We carried out an experimental and theoretical study of the electrical conductive properties of the tissues of the vestibular labyrinth. Using the theory of dynamic systems and experimental data on measurements of the amplitudes of the electrical signal at the end of the vestibular nerve, we calculated the transfer function of the vestibular labyrinth and investigated its frequency dependence. It is shown the transfer function tends to its asymptotic value with increasing frequency. We found that the transfer function of the vestibular labyrinth for stimulating impulses emanating from the electrode located in the posterior semicircular canal is significantly less than for stimulating impulses from the electrodes located in the superior and horizontal semicircular canals.

Sensorineural Hearing Loss in Leukemia: A Case Report Showing Intravascular Coagulation in the Cochlea and Vestibular Labyrinth

Introduction: Sensorineural hearing loss frequently has been described in patients with leukemia, and in fact, hearing loss may be the presenting symptom of this disease. However, the pathogenesis of sensorineural hearing loss in leukemia is not well understood. Objective: To describe the temporal bone histopathology in 1 patient with leukemia and sensorineural hearing loss. Methods: The histopathology of the temporal bones of 1 patient with chronic myelomonocytic leukemia who suffered well-documented bilateral sequential profound sensorineural hearing loss 4 months before death was investigated using light microscopy. Result: There was evidence of ischemic necrosis of the neuroepithelium and intravascular fibrin micro-thrombi suggestive of intravascular coagulation in the cochlea and vestibular labyrinth. Conclusion: Intravascular coagulation may be a contributing factor in the commonly reported finding of hemorrhage in the cochlea in leukemia and may play a role in the pathogenesis of sensorineural loss in some cases of leukemia.