H. B. Perlman

Cochlear Blood Flow in Acoustic Trauma

Some normal values of cochlear blood flow rate, cochlear function (microphonic response to 277 cycles at 90 db), carotid pulse pressure and heart rate are presented along with changes due to excessive acoustic stimulation. The relation of cochlear blood flow to the oxygen demands of the cochlea is considered.

Acute vestibular paralysis in herpes zoster oticus.

A case of herpes zoster oticus is presented in which the lateral and superior semicircular canals of the labyrinth were affected unilaterally. The results of several electronystagmographic examinations are described and correlated with the patients description of symptoms. This case study indicates that disease affecting the lateral semicircular canal is reliably detected by the conventional caloric test. However, the fact that the posterior semicircular canal remained intact could not be inferred from the results of the caloric test in this case. Also, the appearance of nystagmus upon eye closure appears to have been a more sensitive index of the state of the disease process than was the caloric test.

XLIX Sarcoidosis of the Upper Respiratory Tract

Through the cooperation of Dr. Bloch in our Chest Clinic who has been making a special study of sarcoidosis of the upper respiratory tract I have had an opportunity to examine a number of such cases. This chronic granulomatous disease is of interest to the laryngologist for a number of reasons. In the first place clinical and autopsy reports indicate that the nose and throat are involved in a high percentage of cases. This may have etiologic significance.

Respiration of the Cochlea and Function

Brief reversible depression of cochlear respiration was produced in the guinea pig with 0.013 cc of 0.2 mM sodium cyanide perfused into the scala tympani of the basal turn for 80 seconds. Brief reversible depression of cochlear respiration was also produced by systemic hypoxia (respiration with 5% oxygen). When cyanide perfusion was combined with hypoxia, cochlear respiration and function were more severely effected. The effects of cyanide and hypoxia on the terminal cytochrome oxidase of the respiratory chain of enzymes in mitochondria are reviewed.

Temporary Arterial Obstruction: Effect on Perilymph Oxygen and Microphonics

The principal source of oxygen to the cochlea is the arterial blood supply. When blood flow (oxygen delivery) is stopped the reserves of oxygen in the cochlea are very limited and begin to fall in a few seconds. The oxygen reserves drop in a linear fashion and are exhausted in about 100 seconds. The oxygen reserve in the cochlea can maintain normal cochlear function (microphonic output) for only a few seconds after blood flow stops. After this cochlear function drops reaching a 50% level in 40 seconds. With return of blood flow cochlear oxygen tension recovers in a linear manner while cochlear function recovers more rapidly. Full recovery of normal blood flow, normal oxygen reserves and cochlear function can be obtained even after 6 minutes of obstruction of the internal auditory artery. When blood flow resumes the initial velocity may be two to three times normal. In a short period (i.e. 100 seconds) depending on the duration of the obstruction, blood flow velocity returns to normal. This is an indicatio...