A CASE OF DIPLACUSIS BINAURAFIS, 
WITH REMARKS. 
A CASE OF RESTRICTED RANGE OF 
AUDITION. 
SWAN M. frURNETT, M.D., 
OF WASHINGTON, D. C. 
Reprinted from the “ Archives of Ophthalmology and Otology,'1'1 
Nos. 3 and 4, 1S76. 
N E W YORK: 
WILLIAM WOOD & COMPANY, 27 GREAT JONES ST. 
1877. A CASE OF DIPLACUSIS BINAURALIS, 
WITH REMARKS. 
A CASE OF RESTRICTED RANGE OF 
AUDITION. 
SWAN M. BURNETT, M.D., 
OF WASHINGTON, D. C. 
Reprinted from the “Archives of Ophthalmology and Otology." 
Nos. 3 and 4, 1876. 
NEW YORK: 
WILLIAM WOOD & COMPANY, 27 GREAT JONES ST. 
1877. A CASE OF DIPLACUSIS BINAURALIS, WITH 
REMARKS. 
By SWAN M. BURNETT, M.D., of Washington, D. C. 
G. K., a German professor of music, aged 59, noticed for the first time, 
about ten years ago, that an A tuning-fork, when held before the right ear, 
sounded from § to a tone fiat. This he thought to be very strange : but 
as it caused him no inconvenience in his profession, or otherwise, he paid 
but little attention to it, always employing the left ear in tuning instru- 
ments and when using the tuning-fork. 
On being questioned as regards the circumstances under which this 
phenomenon made its appearance, he remembers at about that time, or 
previously, he noted a loss of hearing power, subjective noises, and some 
vertigo. 
Since early life, however, he has been troubled more or less with ver- 
tigo even more than now, though he had a severe attack last spring. He 
also has had frequent attacks of “nervous headache,” which were re- 
lieved by emesis or sleep. These headaches are now less frequent than 
formerly. 
Seven months before calling my attention to his condition (July 29th, 
1876), he accidentally noticed that the A fork, when held before the right 
ear, sounded as b natural, one tone higher. This change in the state of 
affairs arrested his attention, and he has since been observing it more 
closely, and, in the experiments carried on under my directions, the follow- 
ing facts have been elicited : 
The A tuning-fork, as stated, when placed before the right ear is heard 
as b natural, but occasionally varies from that tone by one or two com- 
mas (} to | of a tone). When the fork is placed on the glabella, it is 
heard as a, but when on the mastoid process of the right side as b natural, 
the same as when held in front of the auricle. When the fork is placed 
on a sounding-board or on a common table, and the ears are applied to 
it, no difference is observed on the two sides. 
On the piano a difference is noted, beginning at the contra 
A, which sounds in the right ear as a sharp, or about five 
commas higher. This difference lessens about one comma 
for each octave in ascending, until it disappears altogether. Swan M. Burnett 
The violin was used, held close to the ears, and the vibrations were 
made both by a bow and by plucking the strings, but no difference could 
be detected. 
The same want of success followed experiments with wind instru- 
ments. 
The timbre of the pseudo-tone of the fork and piano had, if there were 
any difference, a little less brilliancy than the tone as heard in the other 
ear. 
His general health at present is good, except for a rheumatism of the 
right-side leg especially—an affection from which he has been a sufferer 
all his life. 
A watch, which is heard at eighteen inches on the left side, is heard at 
one inch on the right. The membrana tympani is healthy in appearance ; • 
he has occasional noises, but there is no discharge from the ear, nor has 
there been at any time. About the time he first became awTare of the 
diplacusis, however, he noticed that when he struck a note on the piano 
particularly hard, it gave a sensation of pain in the right ear. The Eus- 
tachian tube is pervious. 
Accurately observed cases of diplacusis seem to be rare. Prof. 
Knapp, in these Archives, Vol. I., p..365, records a case, and 
makes mention in more or less detail of the other cases that had 
been described up to that time. These cases comprise two re- 
corded by Moos, and one by von Wit tick. 
In this paper Knapp gives a rational explanation of the phe- 
nomena of the affection in accordance with the present accepted 
views in regard to the physiology of music, and offers sugges- 
tions as to the proper study of cases that may come under notice 
in future—suggestions of which I have availed myself in the 
instance under consideration. 
In order to obtain a clear understanding of the case just related, 
it will be best, perhaps, to repeat, briefly, the principles, physio- 
logical as well as pathological, that enter into a consideration of 
the subject. 
The membrana spiralis, according to the theory of Helmholtz, 
is to be considered as a stringed instrument possessing a fibre 
which by its length and tension is tuned to each perceptible tone 
of the musical scale. The two cochleae are tuned, in a normal 
condition, in unison. 
In diplacusis binauralis there is supposed to be an inter- A Case of Diplacusis Binauralis. 
ference in the tuning of one of the cochleae, such as to destroy the 
harmony that should exist between the two, in order to insure 
binaural audition. 
This interference may be such as to occasion a false higher, or 
a false lower tone in the affected ear. 
In the case reported by Knapp the pseudo-tone was lower # 
than in the healthy ear, which would correspond to a tightening 
of the fibres. In von Wittich's case the pseudo-tone was higher 
with a corresponding relaxation of the affected fibres. 
In our case the pseudo-tone was first lower, and, in accordance 
with this theory, associated with a tightening of Corti’s fibres. 
Subsequently it was higher, with a corresponding relaxation of 
the affected fibres. 
In von Wittich’s case the diplacusis was limited to the middle 
octaves of the piano ; in Knapp's to the middle and next higher ; 
in ours it extended over about four octaves, beginning with the 
contra A. 
In Knapp's case the difference between the two tones was two 
whole tones, and disappeared gradually ; in von Wittich's it was 
one half-tone, and not variable ; in ours it was not only variable 
from time to time, but changed with the octaves, varied with the 
character of the tones, and for some kinds of tones was rtot per- 
ceptible at all. 
In all the reported cases, except in ours, there was an accom- 
panying catarrh, acute or chronic, of the middle ear. 
Any discussion of the pathology of diplacusis must, from the 
nature of the case, be entirely speculative in its character; and, 
while agreeing with Knapp, that “it is more important to collect 
facts in relation to this anomaly than to seek for a theory,” we 
cannot but think that an examination of the facts thus far accumu- 
lated will not altogether fail to yield some good fruit. 
In the cases hitherto reported there has been a high degree of 
probability that there was a propagation of a morbid process from 
the middle ear to the labyrinth, since in all there was present an 
* There is an error in Knapp'j report (l.c., p. 369), where he says that the tuning- 
fork was heard higher on the affected side. Further on he says it was heard lower, 
and from the context we judge this to be the case. In this same connection we would 
call attention to a singular mistake made by Roosa, in his reference to this case, in his 
textbook. In alluding to it, he says: “Both ears of this patient were affected with 
double hearing.” (P. 490.) 6 
Swan M. Burnett: 
acute or chronic otitis media. And if we accept the theory 
offered to us in explanation of the phenomenon, we have to deal 
with an exudation into the cochlea, or at least with an increase 
of intra-cochlear pressure. That the former is the morbid condi- 
tion, would appear the more likely, since the false tuning has in 
all the cases been confined to a limited number of fibres, and does 
not affect them all, as must have been the case if there were a 
general increase in the pressure of the liquor Cotugni. That the 
latter might occur, however, cannot be denied. 
It is a very pertinent question whether the symptoms accom- 
panying diplacusis are such as we are accustomed to look for in 
cases where there is an increase of pressure on the terminal fibres 
of the auditory nerve. 
In none of the cases have subjective noises, vertigo, etc., been 
at all prominent symptoms. In none of the cases hitherto re- 
corded are these symptoms mentioned, and in ours they were by 
no means prominent, and the fact of their existence was elicited 
only by questioning. One feature in our case, which points to 
pressure in the labyrinth, is the hypercesthesia, which was present 
early in the history of the affection, if we can accept as evidence 
of this the pain caused by loud sounds. 
As to the character of the exudation causing pressure in 
these cases, it must either be inflammatory or sanguineous. In 
our case, if there were inflammatory action going on in the laby- 
rinth, it must have been idiopathic—a fact denied by some writers ; 
but, on the other hand, it lacked many of those intense features 
which have been asserted by those who contend for a primary 
inflammatory condition of the labyrinth to belong to the affection. 
But, is it not possible that the changes which produce diplacusis 
may in some cases not be seated in the labyrinth at all, but in the 
cerebral centre of audition ? We simply throw this out as a sug- 
gestion, and will reserve its further consideration for its proper 
place in a paper on the connection between nervous deafness and 
certain nervous affections. 
There are some features of our case, peculiar to it, which are 
worthy of attention. 
It is remarkable that the pseudo-tone varied with the different 
octaves and with tones of different timbre, and for some kinds of 
tones was not perceptible at all. In the experiments, it will be A Case of Diplacusis Binauralis. 
noted that the nearer the tone approached to a simple tone—the 
fewer over-tones it had—-the more pronounced was the pseudo-tone 
and the greater the interval between it and the tone as heard in the 
healthy ear. The difference between the two, when a tuning-fork 
was used which gives a simple tone, was one tone ; in the piano, 
in the lower octaves, where the over-tones are few, the difference 
was less marked, being one half-tone, but still greater than in 
the higher octaves where the over-tones are more numerous. In 
the violin, where the over-tones are many, no pseudo-tone could 
be detected. I have not been able to frame in my mind a satis- 
factory explanation of this curious fact. The nearest approach 
to it is this : If you take, for the pseudo-tone, a fundamental with 
a large number of over-tones, especially the middle and higher 
octaves, there are likely to be among these a number which, 
either in themselves or their harmonics, correspond to the funda- 
mental of the tone as heard in the healthy ear. These over-tones 
will reinforce the tone as heard in the healthy ear, and give, so to 
speak, apreponderance to that tone. Applying here the principles 
that we have seen in action in strabismus, we can readily suppose 
that the false tone can be to a greater or less extent suppressed. 
In this manner we can satisfactorily explain why the diplacusis 
has never caused him any serious inconvenience. The suppres- 
sion of the pseudo-tone is rendered the easier on account of its 
being much less intense than the tone as heard in the healthy ear, 
just as the more feeble of the double images in diplopia is more 
readily suppressed than the distinct one. 
Bearing in mind these facts, we are able to infer that diplacusis 
may be a much more common affection than the record of cases 
would lead us to suppose, since it can be so readily overlooked. 
In our case it would never have been brought to light had the 
Professor not been accustomed to use the tuning-fork, and the 
difference in pitch would probably have passed unnoticed had he 
not been a musician. A CASE OF RESTRICTED RANGE OF AUDITION. 
By SWAN M. BURNETT, Washington, D. C. 
Mrs. M. P. S., aged about 47, suffered from her infancy to her twelfth 
year with earaches, which, however, were never accompanied by a dis- 
charge. 
The peculiarity in hearing under which she labors dates from her ear- 
liest recollection, and has never seemed to change from the time she first 
began to notice it until now. This peculiarity consists in the inability to 
hear certain tones. The singing of most birds is not heard by her at all ; 
neither is whistling, unless it be in a low key; and she has never heard 
the chirp of a cricket. Words spoken in a whisper are totally incompre- 
hensible to her. Bells of deep tone are readily enough heard, but small 
dinner-bells of high pitch are indistinguishable. Conversation, when 
carried on in an ordinary tone, is understood ; but when words are spoken 
in a high key, as when one is speaking to an audience, she finds consid- 
erable difficulty in following the speaker. The ticking of some clocks is 
heard distinctly. When my watch (an English lever) was pressed strongly 
against the auricle, she experienced a sensation ; but whether it was the 
auditory nerve or only the nerves of common sensation that were affected 
by the vibrations, it is difficult to say. 
In testing on the piano, I found that she distinguished the notes one 
from the other very readily, until I came to the second C above the 
middle C of the instrument. All notes above this, she said, appeared to 
her alike ; she could distinguish no difference between them. They had 
a low, dull, obscure sound, as if a table were tapped with the tip' of the 
finger. The lower notes of the piano were much more brilliant in timbre 
than the higher. 
The MTT., on inspection, were of the natural brilliancy. The light 
spot in the right was of the normal shape and position; in the left it was 
interrupted in the middle of its course; the Eustachian tubes were patent, 
—no evidence, in other words, of any present or past inflammatory trouble 
in the middle ear. 
She has never in her life suffered from vertigo, and has never had any 
subjective noises. 
Other members of her family have suffered from earaches ; but she alone 
has this limitation in the range of audition. In her younger years she Swan M. Burnett: Restricted Range of Audition 
learned music on the piano, but always played mechanically, and could 
never learn “by ear,” though she strove hard to do so. 
In addition to her defect in hearing, she has also a marked peculiarity 
in speech. None of the hissing sounds are pronounced. They are sub- 
stituted by the smooth sound of th, or are glided over without any defi- 
nite sound bv the simple expiratory sound of ha. Thus the words Mister, 
Sampson would be pronounced Mithter, Hampthon. It was a long time 
before she could learn to pronounce the word champagne correctly, call- 
ing it invariably campagne. 
It is these words, too, where the hissing sounds occur, which she ex- 
periences the most difficulty in understanding. Sometimes they must be 
spelled or even written before she can comprehend them. 
In her youth she had her frenurn clipped by a surgeon, under the im- 
pression that her lisping was caused by tongue-tie. It is scarcely neces- 
sary to state that no relief followed the operation. 
The perception of the higher musical tones and their patho- 
logical significance have already been treated of, in extenso, in 
these Archives, by the able pen of Dr. Moos (Vol. III., Part I., 
p. 113, and Vol. IV., p. 469), and it would be superfluous for us 
here to enter into a discussion of them. Besides, we are not sure 
that the case reported has any bearings in that direction. It is 
more than probable that the defect was congenital. It is true 
there was a history of earaches, but that history was not such, 
neither were the present indications such, as to point to a con- 
dition of affairs that would be likely to bring about the defect 
under consideration. 
In all of Moos’s cases there were subjective noises ; in ours there 
were none, and never had been. The condition of the MTT. 
in Moos’s cases was such as to lead to the diagnosis of “ chronic 
catarrah of the middle ear,” while no such evidence existed in 
our case. Moreover, we think that the fact that the limitation 
was abrupt and occurred at precisely the same note in each ear 
would militate against the idea of its being of pathological origin. 
It would be hardly probable that the modification of labyrinthine 
pressure from any pathological cause would be so exactly the 
same on both sides. 
It is well known that the capacity for hearing very high notes 
is various in different individuals of otherwise normal hearing 
power, and also differs in different animals ; and the only interest Sivan M. Burnett: Restricted Range of Audition. 
that attaches to our case in that particular is, that the limitation 
is very much in excess of what is common. 
The two points to which we would call attention, in connection 
with the case, are physiological rather than pathological. 
It will have been observed in the history of the case that, 
though all notes above c" (ut4) ceased to be musical in their 
character and could not be distinguished one from the other, they 
were still, in a certain measure, perceptible. 
This would appear to substantiate the theory that the percep- 
tive auditory apparatus has two distinct functions with two sepa- 
rate organs for their performance. The office of one of these 
organs is to take cognizance of sound as noise, the other of sound 
as music. The cochlea is now accepted to be the organ for the 
perception of musical sounds, and in our case it is fair to presume 
that the fibres of that part of the lamina spiralis which corre- 
sponds to the higher notes are either absent or are in some man- 
ner hindered in the proper performance of their office ; while 
that organ which presides over the perception of aerial vibrations 
as noise is to a greater or less extent intact. 
The fact, that the lower notes of the piano were more brilliant 
in timbre than the higher, finds its explanation in the fact that the 
over-tones (which give the tone its brilliancy) of the upper notes 
lie largely in that portion of the musical scale which is beyond the 
limit of audition. 
It is easy to trace the connection between the defect in hearing 
and the peculiarity of speech. It is certain that we make the 
sound of our own voices the guide to our articulation. If we can- 
not hear what we say, we cannot fashion the delicate and complex 
apparatus for articulation so as to enunciate the sounds we have 
in our minds to utter. The lady, whose case we have been con- 
sidering, having never heard the hissing sounds, is not able to 
judge whether she articulates them or not, and the consequence 
is that they are either glided over or substituted by some other 
sounds which appear to her mind to be their equivalents. 
It is not improbable that many cases of “ lisping” have their 
origin in this same condition of the auditory apparatus ; and in all 
such cases it would be well to make an examination of the range 
of audition.