Sudden Deafness – A Critical Evaluation of Pathogenesis and ‘Cure’

Abstract

Objective: To discuss the possible etiology, pathogenesis and ‘cure’ of idiopathic sudden deafness (SD). Method: A review was made of different methods for the study of inner-ear physiology, especially its microcirculation, relating them to clinical evaluation and praxis for SD. Results: Cochlear blood flow (CBF) can be measured quantitatively with the microsphere method in animals. Direct qualitative measurements can be performed using the laser Doppler method. The CBF is partly autoregulated, but to a lesser degree than cerebral blood flow. Sympathetic stimulation decreases CBF up to 25%. Noise does not influence total CBF but seems to reduce blood flow in the lateral wall. Nicotinic acid, hemodilution and osmotic drugs increase the CBF proportionally. Carbogen increases the CBF but also creates acidosis. Treating patients with SD in accordance with these findings does not show any convincing effect compared to no treatment. Conclusion: More and more diseases have been identified which can have SD as a symptom. It is important to investigate to identify these treatable cases. Idiopathic cases should not be exposed to hazardous systemic medication or surgery. Local treatment through the round window will be the treatment modality for the future, but more basic research is necessary.

Assessment of diagnostic approaches to idiopathic sudden sensorineural hearing loss and their influence on treatment and outcome

“…The results that patients with an hearing loss in the mid frequency region had the best recovery rate has been reported earlier in several studies [2,5,18] and can be explained on the basis of a vascular theory for ISSNHL: In the cases when two arteries are supplying the cochlea, which occurs in about 50% of the cases [19] and where the main internal auditory artery is occluded distally to the branching of the anterior vestibular artery, one would theoretically expect a hearing loss in the lower and mid frequency region of the cochlea which has a chance of recovery through collaterals from the second main artery [20]. The same reasoning can be applied to the five patients in the present investigation with vascular aberrations that were seen on MRI, all of whom had low frequency hearing loss and experienced none or moderate improvement.…”

“…The same reasoning can be applied to the five patients in the present investigation with vascular aberrations that were seen on MRI, all of whom had low frequency hearing loss and experienced none or moderate improvement. They may have had the same occlusion of the main auditory artery, but with no collateral supply from a second artery [20].…”

Corticosteroid Treatment of Idiopathic Sudden Sensorineural Hearing Loss

“…Treatments used have been built on different hypotheses of the etiology such as vascular compromise (1)(2)(3), viral/inflammatory causes (4) or perilymphatic fistula (5,6).…”