RESULTS OF THE WORLD'S FAIR HEARING TESTS 



561 



only for the youngest group because we are primarily concerned with 

 early detection of deafness. Limits for older groups can be obtained 

 in a similar manner. 



The table indicates that a smaller hearing loss is significant at low 

 than at high frequencies. At the higher frequencies a smaller loss is 

 significant for girls than for boys. The percentage of the youngest 

 group at the Fairs falling outside of the 2a limits is given in Table 17. 



TABLE 17 

 Percentage of Children with a Significant Amount of Hearing Loss 



Use of the Sa limits would lead to percentages about half as great. 

 It is of interest to note that the 2o- limits are smaller than the amounts 

 of hearing loss which ordinarily constitute a handicap. In other 

 words, a hearing acuity test may have diagnostic significance before 

 the hearing loss is great enough to produce appreciable functional 

 impairment. 



Incidence of High-Tone Deafness arid of Adenoid Growth 

 The characteristic difference between men and women in the hearing 

 of high tones seems now to be well established. It has been previously 

 observed by Bunch and Raiford,'' by Ciocco ^^ and more recently by 

 Beasley in a survey of hearing during the health census of 1936.^^ The 

 reason for the difference is not known. It may be occupational in 

 part, although the difference is in evidence in the youngest age group. 

 Recent work reported from Johns Hopkins University .^"^ indicates that 

 children with high-tone deafness frequently show pronounced lymphoid 

 tissue growth at the openings of the Eustachian tubes in the throat. 

 In a number of cases, the deafness was cured or held in check by 

 removing the tissue and inhibiting its growth by irradiation with 

 radium during the adolescent period. 



If there is a connection between adenoid growth and high-tone 

 deafness, one would expect a greater incidence of adenoid growth in 



^^ A. Ciocco, "Observations on the Hearing of 1980 Individuals," Laryngoscope, 

 42: 837-856, Nov. 1932. 



'^ W. C. Beaslev, National Health Survey, Hearing Study Series, Bulletins 5 and 6, 

 United States Public Health Service, Wash. D. C. (1938). 



^^ S. J. Crowe and J. W. Baylor, "Prevention of Deafness," Jour. Amer. Med. 

 Assn., 112: 585-590, Feb. 1939. 



