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WORD DEAFNESS.
Cases are now diagnosed from time to time as being congenital word deafness. The condition is
a rare one—indeed it is just 10 years since the first case was described by me, and most cases hitherto
recorded have been noted among our London children by Dr. Thomas. In certain children, usually
with general mental defect, words heard act in a kind of reflex way, and are immediately reproduced as
a parrot speech (echolalia). The mechanism of hearing and production is perfect, but the structures
concerned in understanding the words heard are wanting. In the ordinary mentally defective child
this is always taken as indicating considerable and grave mental defect, showing want of development
of the higher auditory speech centres. The memories of words are stored in the brain in various ways,
but spoken words are heard by the ear : are seen by lip-reading ; can be felt by motor speech, and
understood by first repeating the words. The ordinary method of learning word heard is by development
of a centre, the higher auditory (word) centre. Where this fails speech may be learnt by the
visual (lip-reading) centre becoming specially educated, or by the motor (spoken) word centre developing.
The highest intellectual centres for understanding words can be reached through any of these routes.
Word deafness then may be associated with general mental defect or in rare cases may be isolated, the
rest of the brain being normal, the word centre alone impaired. Besides this variety, a few children
are seen from time to time where obscure hysterical or psychical causes seem to have interfered with
normal speech evolution. In one case, apparently of a functional nature, and originating in a fright, a
boy of nine who had not spoken for years was made to count numbers in an audible voice at the first
examination by simple suggestion strongly maintained. Some of the doubtful cases seen at the Head
Office have been followed up in the deaf schools, by careful testing early this year by Dr. E. Jones. He
thinks these cases have been too much assimilated in their mechanism to word blindness, to which they
do not bear resemblance. He does not credit the "word hearing centre" hypothesis, although even
if it is wrong, it was this hypothesis which by analogy led to deduction from the earlier observed word
blindness, and to the search for and discovery of this much rarer condition of congenital word deafness.
In addition to the mentally defective there are clinically a number of cases which fulfil the
simple definition of persons able to hear, but unable to understand what they hear. Of two children
with the same degree of deafness one may understand the meaning of words heard much better than
the other. This may be due to a congenital weakness of the hypothetical auditory word centre, or
to some psychical inhibition due to infantile psychasthenia, hysteria, or congenital debility. In these
last cases the defect is only apparent. The words are heard, registered in the memory, and even subconsciously
understood, and all that is lacking is conscious apprehension of the meaning, as happens
when a person under strong emotion cannot take in the meaning of words addressed to them. If
such a psychical cause arises early in life, after this has begun to act not only is there continuous amnesia
for the meanings of words heard, but the case also may differ from that in an adult in that there is no
further formation of a conscious vocabulary with any meaning attached. The child therefore is in many
respects like a mentally defective one, and such cases have often, or perhaps generally, been neglected
as imbecile. The profound secondary consequences of speech, or of want of speech, from the educational
point of view are not always realised, but become quite comprehensible from this point of
view. There is probably a close relation between deafness and word deafness, in that most cases,
though not all, show some deafness. The analysis of this apparent deafness is very difficult. How