/7,
THE DEAF CAROLINIAN
PUBLISHED BY THE NORTH CAROLINA SCHOOL FOR THE DEAF, MORGANTON. N. C.
VOL. XXX. SATURDAY, NOVEMBER 1, 1924. N0.8
“AID TO HEARING;” A REVIEW
A Discussion of Various Devices to Aid Hearing Which Will Appeal
Especially to Hard of Hearing and Their Friends.
By ENFIELD JOINER, in The Annals
The Annals of Otology, Rhinology ami
Laryngology, (September, 1923: vol. 32,
no. 3; St. Louis), has recently published
a paper on “Aids to Hearing.” by Dr. Gor¬
don Berry, of Worcester, Mass. This pa¬
per was originally presented at a meeting
of the Eastern Section of the American
Laryngological, Rhinological and Otologi-
cal Society, at Providence. R. I. It was,
therefore, designed for a special group of
the rrtedical profession, but it contains
much of general interest for the lay-
reader as well as for the professional
reader. Written in a pleasing, non-techni-
cal style, from a sympathetic viewpoint,
at er an obviously exhaustive study of
the subject, the article will appeal especi¬
ally to the hard of hearing and their
friends.
Says Dr. Berry, “The subject naturally
divides itself into a consideration, first, of
the mechanical devices to aid hearing that
are on the market; second, lip-reading as
a very important remedy ; third, of the
cooperative work now being done in this
country for the deaf.” ,F°r sometime, Dr.
Berry has been prominent among that
school for otologists who hold that it
comes within the province of their work,
not only to try to prevent and cure deaf¬
ness, but to foster all movements which
look toward removing its handicap: conse¬
quently, he believes in the efficacy and
the necessity of a close cooperation ire-
tween doctors and teachers of lip-reading
He has already made several excellent
contributions to the literature of adult
lip-reading, and in this paper he again
goes on record as strongly favoring an in¬
tensive program of instruction for tiie
student. “Hard concentrated effort and
continued practice seem essential to the
best accomplishment," is the statement
with which he concludes the second divi¬
sion of his article. These are interesting
topics, but for the readers of the Annals,
the chief value of the paper lies in its in¬
formative discussion of mechanical aids
to hearing.
Dr. Berry tells us there are three types
of such contrivances. They are classified
as follows: the various forms of rubber
or membrane, which are to be placed in
the auditory canal and which are popu¬
larly known as artificial eardrums; the
born or tube, which gathers up sound
waves much as the hand cupped about the
ear does; and electrical instruments.
In regard to the first type, he admits
that “by actual test the hearing may be
better after its insertion," but he warns
the user the danger of injuring the canal,
or of aggravating or creating an inflam¬
mation which may have serious conse¬
quences. He believes that such appliances
are to be condemned “because they are
not intelligently used.”
The second type is the simplest of all
devices and can in no way harm the ear.
The Globe Phone Company manufactures
and widely advertises nine different in¬
struments of this type, all of them some
form of the horn or tube which will catch
a larger volume of sound than the unaided
ear. He recommends these as especially
adapted to the needs of the aged deaf. The
advantage of this type is that “it trans¬
mits sound exactly as it is received with¬
out accentuating certain types of sound
and lessening others.” Under this class of
instruments he places those which make
use of bone conduction. The best of these
is a hard rubber fan held against the
teeth, which receives sound impressions
and carries by way of the teeth to the
bones of the skull and thence to the inner
ear. Though differing in appearance from
its brothers of the horn and tube type,
this instrument also transmits sound in
its natural state, that is, unamplified or
modified in any way. Its principle is the
same, though it effects its delivery to the
auditory nerve by another route.
The third type, the electrical device, is
discussed at length. Dr. Berry’s observa¬
tions lead him to conclude that “by reason
of its finer control and better adaptation.”
this type is gaining supremacy. He gives
a list of the different standard ear-phones;
the Acousticon, the Gem. the Globe, the
Harper, the Magniphone, the Mears, the
Midget Phonophor, the Opera Type which
Miss Bruhn introduced recently from Ger¬
many. the Potter and the Williams Ar¬
ticulator. Basically, all these employ the
mechanism of the telephone. They are
being steadily perfected; their inventors
are continually experimenting, eliminat¬
ing unnecessary parts, simplifying bat¬
teries, improving cords. We are told one
worker, Mr. Charles W. Harper, spent two
years trying to find the best material for
the diaphragm of his instrument.
The latest of the • electrical devices is
the Vactuphone. the invention of Mr. Earl
C. Hanson. The latter was one of the
wireless experts connected with the Am¬
erican Expeditionary Force to France.
In his experiments with the audion ampli¬
fier, he found that he could use trees as
receivers, and enable men at listening
posts to hear the enemy’s plans, and also
to get messages to aviators from the
ground. Mr. Hanson had a deaf mother,
for whom he had been able to find no en¬
tirely satisfactory hearing instrument.
Dr. Berry tells us that his eagerness to
help her brought about the Vactuphone,
to which the principles of wireless trans¬
mission are applied.
Deductions concerning the worth of this
class of devices are so clearly stated and
so scientifically suppoited that it seems
best to quote at length: “An ear-phone
transmitter lends itself to considerable ad¬
justment. Two factors are present. The
first factor regulates the pitch which is
transmitted through the cord to the re¬
ceiver and the ear, the second determines
the intensity of that sound. As we know
experimentally that certain patients,
though deaf, can hear fai more clearly at
certain pitches than others, and, on the
othe: band, that where .here is a partial
nerve deafness superimposed, a greater
intensity both tires and drowns out the
sound, it is clear that these two factors of
distinctness or pitch, and volume or inten¬
sity. must be intelligently controlled. Does
not this suggest where the otologist may
contribute by determining the degree and
type of deafness? * * * How much gain
can a deaf patient expect from a properly
adjusted earphone? A conservative
estimate would double the hearing in the
average catarrhal cases. This is a real
gain.”
At this point. Dr. Berry discusses the
need for individual adjustment. “Manu¬
facturers and deaf persons alike say that
one must train himself to use the instru¬
ment. Certain types of noises art much
magnified, others are scarcely audible.
The user learns how to adjust the rheo¬
stat, dimming the loud noises and increas¬
ing the soft. Adventitious noises which
the instrument accentuates, he learns now
to pay no attention to. In nerve deafness,
these adventitious noises trouble more, and
here the earphone offers no aid, but jan¬
gles and tires the ear. Where there is a
catarrhal, as well as a nerve deafness, an
instrument which accentuates detail with¬
out undue volume will help the catarrhal
phase and not tire the nerve phase. It is
claimed that these instruments improve
the heai'ing. There is some logic in this
contention. We know that disuse of a
nerve causes its atrophy.”
The importance of the otologist's being
able to make accurate and definite recom¬
mendations as to types of instruments best
suited to their patients is stressed. He
Continued on Page Two
