On the Problem of Disposition in Perceptive Deafness

Abstract

In 1939 the author discussed on the close relationship of hereditary deafness with Beriberi in V. Bi-deficiency. Consecutively the author gave his own opinion that the etiology of the perceptive deafness, especially in that of unknown causes, shoud be found in thiamine deficiency. Futhermore, even by the latent thiamine deficiency, it might disturb the next generation, and the possibility of the geneimpairing by nerve deafness was discussed. In the perceptive deafness of known etiology also the predisposed thiamine deficiency can play an important role as the developing factor of its outbreak. In 1948 TOMOMATSU found the positive Sawada's urinary reaction of pyruvic acid increase by 75% of nerve-deafness cases of unknown etiology.
This special condition is based upon alimentary situation of our nation, characterized by unbalanced carbohydrate rich diet which requires too much use of carboxylase, to some extent, I believed.
Acetylcholine is well known as a significant chemical substance necessary for sensorineural activity mechanism. It relates also to auditory perception in various portions. We know the existence of pseudo-cholinesterase in plasma and true cholinesterase in red cells. The content of cholinesterase in plasma of normal person has been measured undoubtedly as almost constant value to a certain degree until comparatively lately, however, what is interesting is that recently a fact was recognized in pharmacogenetics, there are few exceptional individuals of poor cholinesterase among normal persons. And it was reported that there exists inherent tendency by it.
Lately we measured the levels of cholinesterase of serum in 10 normal persons and on the other side that of 30 patients with sensori-neural deafness. The average enzymatic level of cholinesterase in perceptive deafness as 0.77±0.05, presented lower value than that of normal control group as 0.92±0.05. On the other hand the intimate relationship of cholinesterase with thiamine deficiency has been noted since MINz (1937) etc. The cholinesterase is an inhibitor of thiamine.
Thus the inherent enzymatic disorder will develop to a nerve-deafness of unknown cause with symmetrical flat audiograms, when they get an endogenous manifestation in their younger days.
The metabolic disorder by thalidomide embryopathy or by maternal rubella almost in the same way alter the organogenesis and can cause an abnormal pattern of enzyme activity.
Congenital distribution of the inner ear vessels may play a certain role as disposition former. Functional states of the inner ear vessels can be influenced by inheritable nature of the autonomic nervous system. These above-mentioned factors should be related in various ways to bear perceptive deafness. I should like to conclude the inheritable enzymatic disorder of the auditory organ may produce a recessive disposition to provoke the perceptive deafness.