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Journal of the association of physicians of india • vol 63 • march, 2015
Georg Von Bekesy - Visualisation of Hearing
Geeta Gore*, J V Pai-Dhungat**
Georg Von Bekesy - Stamp - Hungary 1988 Model of inner ear, with frequency curve of basilar membrane.-Sweden-1984
G
eorg Von Bekesy (1899-1972) was born in
Budapest in 1899. He graduated in 1920
from Bern, Switzerland and took his doctorate
degree in Physics from the University of
Budapest in 1923.
Bekesy joined the research laboratory of the
Hungarian Telephone System and worked in
their laboratories from1923 to 1946, where he
was mainly concerned with problems of long
distance telephone transmission. The eclectic
and efficient environment of this laboratory
allowed him to spend considerable time in the
autopsy rooms of hospitals, to study the ear as
a main component of the transmission system.
As a communication engineer in Budapest, he
was studying the mechanical and electrical
adaptation of telephone equipment to the
demands of the human hearing mechanism.
His search for the answer to the fundamental
question of “How much better is the quality
of the human ear compared to any telephone
system”, has added volumes to our presentday knowledge of hearing.
Professor & Head Department
of Audiology & Speech
Therapy-T. N. Medical College
(Retd.), Mumbai; **Professor of
Medicine, T. N. Medical College
(Retd.), Hon. Physician Bhatia
Hospital, Mumbai
*
In 1943, after fifteen years of studies, he
published the classic theory of travelling
wave, which replaced the earlier Helmholtz
(1885) resonance theory, widely accepted at
that time. Helmholtz, had contended that the
basilar membrane in cochlea contain a series
of resonators, which are under differing
amounts of tension in a manner analogous
to tension on various tuned piano strings,
each of which responded to sound waves of
progressively higher frequency. The basic
tones plus overtones caused the resonators
to react in a specific pattern, so that identical
notes sounded by different instruments were
distinguished by the ear.
However, Bekesy (1948) demonstrated that
the basilar membrane is under no tension at
all. Further, he postulated that spiral cochlea is
divided in two sections by a basilar membrane,
made up of some 24,000 parallel fibres,
stretched across its width. These fibres become
progressively wider, as one moves along the
cochlea to its tip. He conducted brilliant and
careful experiments using human and animal
cadavers whose auditory mechanisms he
stimulated electrically. He reached the cochlea
by grinding a small opening in the skull
and revealing part of the basilar membrane.
Based on these experiments Bekesy evolved
his travelling-wave theory: According to
this theory, a sound impulse sends a wave
sweeping along the basilar membrane. As the
wave moves along the membrane, its amplitude
increases until it reaches a maximum, then
falls off sharply until the wave dies out. That
point at which the wave reaches its greatest
amplitude, is the point at which the frequency
of the sound is detected by the ear. It is the
shape of the waves, varying in pitch, loudness,
and quality, that gives the brain the data, to
appreciate and to analyse the sound.
Bekesy’s work revolutionised the thinking
of hearing and laid the groundwork for
hearing impairment. He left Hungary in 1946
for Sweden, to join as a guest researcher at the
Technical Institute in Stockholm. It was during
this period that he developed a new type of
audiometer which was operated by the patient.
Due to Soviet occupation of Hungary he
migrated to the US in 1947, and worked at
Harvard University in the Psycho-Acoustic
Laboratory. In 1966, he was offered to lead
a research laboratory of sense organs in
Honolulu, becoming a professor at the
University of Hawaii. He died in Honolulu
in 1972.
Bekesy was awarded the Noble Prize in
medicine and physiology, for his studies of
the travelling wave in 1961. He was the first
physicist ever, to win the Prize in this category.