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A note on the analysis of audiograms of young people
Journal of Sound and Vibration (1993) 161(1), 185-186
A NOTE ON THE ANALYSIS OF AUDIOGRAMS OF YOUNG PEOPLE R. W, FEARN
Department of Public Health Medicine, University of Leeds, 32 Hyde Terrace, Leeds LS2 9LN, England (Received l April 1992) In analyzing audiograms of young people exposed to various noise exposures, we have used a criterion of the number of subjects with hearing thresholds of various values at 3, 4 or 6 kHz in either ear relative to the threshold at 2 kHz. On balance, we have found to be of most use a value of 15 dB or more at 3 or 4 kHz or 20 dB or more at 6 kHz, in either ear relative to the threshold at 2 kHz. Such values will henceforth be referred to as 15/ 20 dB or more. (The extra 5 dB at 6 kHz is accounted for because the calibration factor at this frequency is too low.) The higher the value of the criterion is, the less is the number of subjects with elevated thresholds for reasons other than noise exposure, as may be seen TABLE 1
The numbers of students in the age range 18-25 years with no known noise exposure and with hearing thresholds of various amounts in either ear, relative to the threshold at 2 kHz in various categories
Overall number Unknown reasons Adeno-tonsillectomy Close relative with hearing problems Catarrhal infection Knocked unconscious in accidents etc. Medical inspection of ear Total number tested
10/15 dB or more
15/20 dB or more
20/25 dB or more
53 (37.1%) 31 (21.7%) 10 (7.0%) 6 (4'2%) 3 (2"1%) 2 (1.4°) l (0.7%)
12 (8-4%) 8 (5.6%) 2 (1-4%) -I (0'7%) l (0.7%) --
3 (2.1%) 2 (!.4%) I (0.7%) -----
148
in Table 1. However, if the criterion is made too high then there will be too few subjects in the samples for meaningful statistical analysis. It is not just a matter o f arithmetic convenience. Subjects' aural status is related to the value of the criterion in Table 2. It will be seen that as the value of the criterion increases so does the percentage of subjects reporting hearing difficulties.
TABLE 2
The numbers of subjects reporting hearing problems at various hearing threshold levels; absolute threshold levels at 2 kHz do not exceed l0 dB Heai'ing threshold relative to the threshold at 2 kHz
Total number tested
Percentage reporting hearing problems
10/15 to 14/19 dB 15/20 to 24/29 dB 25/30 dB or more
29 39 25
7% 26% 44%
185
186
L E T T E R S TO T H E E D I T O R
Hence, using a criterion of 15/20 dB or more means that about one-third of the subjects in that category are aware that deafness is beginning to raise its ugly head. The problem, o f course, is to convince the other two-thirds.
A NOTE ON THE ANALYSIS OF AUDIOGRAMS OF YOUNG PEOPLE R. W, FEARN
Department of Public Health Medicine, University of Leeds, 32 Hyde Terrace, Leeds LS2 9LN, England (Received l April 1992) In analyzing audiograms of young people exposed to various noise exposures, we have used a criterion of the number of subjects with hearing thresholds of various values at 3, 4 or 6 kHz in either ear relative to the threshold at 2 kHz. On balance, we have found to be of most use a value of 15 dB or more at 3 or 4 kHz or 20 dB or more at 6 kHz, in either ear relative to the threshold at 2 kHz. Such values will henceforth be referred to as 15/ 20 dB or more. (The extra 5 dB at 6 kHz is accounted for because the calibration factor at this frequency is too low.) The higher the value of the criterion is, the less is the number of subjects with elevated thresholds for reasons other than noise exposure, as may be seen TABLE 1
The numbers of students in the age range 18-25 years with no known noise exposure and with hearing thresholds of various amounts in either ear, relative to the threshold at 2 kHz in various categories
Overall number Unknown reasons Adeno-tonsillectomy Close relative with hearing problems Catarrhal infection Knocked unconscious in accidents etc. Medical inspection of ear Total number tested
10/15 dB or more
15/20 dB or more
20/25 dB or more
53 (37.1%) 31 (21.7%) 10 (7.0%) 6 (4'2%) 3 (2"1%) 2 (1.4°) l (0.7%)
12 (8-4%) 8 (5.6%) 2 (1-4%) -I (0'7%) l (0.7%) --
3 (2.1%) 2 (!.4%) I (0.7%) -----
148
in Table 1. However, if the criterion is made too high then there will be too few subjects in the samples for meaningful statistical analysis. It is not just a matter o f arithmetic convenience. Subjects' aural status is related to the value of the criterion in Table 2. It will be seen that as the value of the criterion increases so does the percentage of subjects reporting hearing difficulties.
TABLE 2
The numbers of subjects reporting hearing problems at various hearing threshold levels; absolute threshold levels at 2 kHz do not exceed l0 dB Heai'ing threshold relative to the threshold at 2 kHz
Total number tested
Percentage reporting hearing problems
10/15 to 14/19 dB 15/20 to 24/29 dB 25/30 dB or more
29 39 25
7% 26% 44%
185
186
L E T T E R S TO T H E E D I T O R
Hence, using a criterion of 15/20 dB or more means that about one-third of the subjects in that category are aware that deafness is beginning to raise its ugly head. The problem, o f course, is to convince the other two-thirds.