Radio age research, manufacturing, communications, broadcasting, television (1941)

iiMii» -^sr^teoBoftieli, f '■ ■ m m ■ as ■ -*it - Ulfe$i«M§w -I J RCA DEVE.OPS STETHOSCOPE Hiiidlt) Sensitioe Ins iment Introduces Mciny Sounds of the Human Body Doctors Have Neoi Seen Able to Hear ^Clarity and Range Increased ANEW acoustic stetliscope has been developed in OA Labo- ratories so sensitive in its range of hearing that it introcices many sounds doctors have nevi heard. In much the same wn that the RCA Electron Microsco): is open- ing unseen worlds in thtsubmicro- scopic realm, this stethcope, de- veloped by Dr. Harry *'. Olson, promises to widen the study of sound within the human ody. The beat of the heart, nonal or ab- normal, respiratory raiJes, peri- staltic squeaks, m u r nu r s and groans, all are amplifiec to facili- tate diagnosis, based ipon the structure of sound. It has been found that le sounds of the body range from » to 4,000 cycles, the full range of \'hich are covered for the first tiie by the new stethoscope. Above 4)00 cycles most of the sounds in th body are so weak that they are lasked by the ambient random nous gener- ated within the body, t is ex- plained that respirator sounds such as wheezes and the ushing of air are of a complex natu ^ There- fore, in designing the nvv stetho- scope to gain maximum itelligence the instrument transmi; all fre- quencies over the range :om 40 to 4,000 cycles without atteuation or discrimination. The ordinry steth- oscope has an effective mge be- tween 200 and 1,500 cycl . The advantages of the ew steth- oscope, according to I'. Olson, come from the fact that t couples the ears of the diagnosti an much more closely to the huian body through the employmeni of a re- versed taper tube which esults in greatly improved matchig of the acoustic elements. Thu sounds produced by the organs of the body are heard more clearly and their range is greatly widened. In fact, so many new sounds aw heard with the instrument. Dr. Olson said, that a filter is built into it to enable the user, by simply turning a knob, to limit the range at will. This was done at the sug- gestion of one of the testing physi- cians in order to prevent confusion until the meaning of the new sounds can be determined through further study. It also makes the stetho- scope a more flexible tool of the doctor. In discussing the practical ap- plication of the acoustic stetho- scope. Dr. Olson pointed out that the conventional type of instrument is not effective with the lower sound frequencies of the heart or with the higher frequencies pro- duced in the chest. The new steth- oscope is expected to be invaluable by making these frequencies avail- able to the physician. "By the application of modern acoustic principles, the new steth- oscope has been developed in which the disadvantages of existing steth- oscopes have been eliminated," said Dr. Olson. "As a result, the per- formance of the new stethoscope is far superior to existing instru- ments." Detection of weak sounds by means of an ordinary stethoscope is limited, according to Dr. Olson, by the presence of noise which blankets the desired sound. "For the most part," he said, "such ex- traneous sounds are caused by the movement of clothing, and room noises, most of which are air- borne. The new stethoscope is in- seiisit' e to air-borne noise because DR. A. D. SUMMERS, COMPANY PHYSI- CIAN, WITH THE AID OF A NURSE, TESTS THE NEW STETHOSCOPE ON ONE OF THE ItCA LABORATORIES EMPLOYEES. DR. HARRY F. OLSON, LEFT, LXl'LAINS TO H. D. BENSON, LABORATORY TECHNICIAN, THE PRINCIPLES OF THE NEW ACOUSTIC STETHOSCOPE. of the high mismatch between the air and the stethoscope." "The ordinary acoustic stetho- scope," Dr. Olson continued, "is one of the most useful instruments which the physician uses in medi- ate auscultation (study of body sounds by the stethoscope). By means of the stethoscope the physi- cian is able to study sounds pro- duced within the heart, lungs, stomach, intestines, or other por- tions of the body, and to determine whether normal or abnormal condi- tions exist as indicated by sounds. Obviously, it is the structure of the sound, which involves the intensity, the fundamental frequency, and the harmonic components, that makes it possible to diagnose normal or abnormal conditions by ausculta- tion." The stethoscope was invented in the early years of the Nineteenth Century by a French physician, R. T. H. Laennec. Until now, there has been very little advance in its basic design. Dr. Olson has been in charge of RCA's acoustics research as related to radio, sound motion pictures, and phonograph sound pickup and reproduction for many years. He is recognized as one of the coun- try's leading authorities on acous- tics. [RADIO AGE 27]