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Effects of adverse perinatal events on hearing
I~TER~ATrlcWrM,OtlNAL
OF
Pediatric
International
ELSEWER SClENCF lRFL.AND
Journal
of Pediatric Otorhinolaryngology
30 (1994) 29-40
Effects of adverse perinatal events on hearing M.S. Razi. V.K. Das*
(Received
I? July 1993; revision received I3 December
1993; accepted 19 December
1993)
Abstract The hearing sensitivity for frequencies 8 kHz through to 18 kHz was compared between children with adverse perinatal factors (study group) and children without adverse perinatal factors (control group). Children in both groups had hearing at levels of 20 dB HL or better in the frequency range between 250 Hz to 8 kHz with normal middle ear pressure. High frequency hearing tests showed that the mean high frequency hearing threshold levels were worse in the study group. Statistical analysis showed significant differences in hearing levels at and above 12 kHz frequencies between the study and control groups. The hearing levels were found to be more significantly affected in females as compared to males, indicating that the high frequency hearing of females was more vulnerable to damage. The results indicate that adverse perinatal events are associated with raised high frequency thresholds in both sexes, especially in females. KeJ words: Preterm birth; Adverse perinatal factors: High frequency hearing thresholds; Sensorineural hearing loss
1. Introduction The human physiological upper frequency limit of hearing has always been a focus of interest to Psychologists and Speech Pathologists. Audiologists have often expressed the clinical opinion that high frequency hearing loss may be a precursor of auditory disorder. The routine pure tone assessment normally is restricted to the range of 250 Hz to 8 kHz, possibly because most of the important sounds of speech and everyday life fall within this range. * Corresponding
Ol65-5876/94/$07.00 SSDI
author
0
1994 Elsevier Science Ireland
0165-5876(94)01012-M
Ltd. All rights reserved
M.S. Rozi. V.K. Das/Inr.
30
J. Pediutr. Otorlhwlur~ngoi.
30 (1994) 29-40
Rosen et al. (1964) [ 181introduced high frequency audiometry to clinical studies. The larger number of studies in the last 30 years is due to the recognition of the greater susceptibility of the basal part of the cochlea for both acquired and inherited sensorineural disease process. It is now recognized that high frequency hearing levels are most vulnerable to noxious influences than are the traditional test frequencies below 8 kHz [3,5,6,8.12,19,21]. The instruments employed in the majority of high frequency audiometric studies have provided air conduction measurements up to 20-24 kHz. The techniques have varied from Quasi free field method [9,16] to the use of special high frequency headphones [5,14,17]. The availability of Demlar 20 K high frequency audiometers and the introduction of electric bone conduction audiometry are useful additions to high frequency audiometry [20]. 2. Materials and methods 2.1. Methodology
Children aged between 7 and 15 years with hearing thresholds 5 20 dB HL [l l] and middle ear pressure between 0 to -100 mmHzO [ 131 were selected for this study. The study group was composed of children with one or more of the following adverse perinatal factors: prematurity, low birth weight, asphyxia, apnoea, respiratory distress syndrome, hyperbilirubinaemia, meningitis, incubator care, ototoxic medi-
Table I Perinatal
problems Study group
I. 2.
Premature Low birth weight
3.
(a) Below 1500 g (b) Between 1501-2500 (c) Above 2500 g Small for date
4. 5. 6. 7.
Hypoxia Respiratory Apnoea Incubation
8. 9. 10.
distress
g
syndrome
Jaundice Birth trauma Mode of delivery: (a) N.V.D.
(n = 28)
M
F
7 5
8
2 3 I2 3 4 I I 3
I 6 4 4
10
3 0
I
N.V.D.,
normal
(n = 26)
M
F
II
I5
5 4 I I vertex delivery;
group
2 I I 7
(b) Forceps (c) C.Sec. (elective) (d) C.Sec. (emergency) Abbreviations:
Control
C.Sec., Ceasarean
section.
14 I 0 0
M.S.
Ra:i.
Table 2 Postnatal
V. K. Das / Int. J. Pediatr.
Otorhinolaryngol.
30
i 1994 i
29-40
problems Study group
Control
group
M
F
M
F
Measles Mumps
9 IO
6 3
5 4
6 6
Measles and mumps No measles or mumps Recurrent ear infections
6 4 I4
2 4 6
2 3 6
4 x II
cation. All the study children had normal hearing in the frequency range of 250 Hz to 8 kHz. Children who had none of the problems mentioned above served as controls. Children with a history of cleft palate, repaired cleft palate, middle ear surgery or presence of congenital or longstanding middle ear dysfunction at the time of the study were excluded. 2.2. Instruments The Peters AP5 with TDH-39 headphone in MX-41 ear cushion was used for testing hearing between 250 and 8000 Hz. The audiometer was calibrated to B.S. 5966 [2]. The output of the headphone was checked as per specification of IEC-303 [lo]. For testing hearing between 8- 18 kHz, the Peters AP5 audiometer with some alteration was used. Beyer Dynamic DT-48 headphones were used. The maximum output of the audiometer ranged between 110-120.5 dB SPL through 8-18 kHz. The dial reading of -10 dB was equal to 40 dB SPL for 8 kHz, 10 kHz and 14 kHz, 30 dB SPL for 12 kHz and 18 kHz and 35 dB SPL for 16 kHz.
Table 3 Mean high frequency Frequency
hearing
threshold
levels (dB SPL) group
(n = 26)
P-value
Study group ‘(n = 28)
Control
Mean
Range
Mean
Range
10
42.8 43.9
40.0-60.0 37.5-52.5
41.1 42.2
40.0-50.0 40.0-52.5
0.09 0.22
I? I4 I6 18
41.4 51.9 64.2 91.0
30.0-87.5 40.0-l 17.5 40.0-I 10.0 57.5-l 15.0
35. I 46. I 49.4 74.5
30.0-55.0 40.0-60.0 35.0-72.5 47.5-97.5
0.03 0.01 0.0 I 0.01
(kHe)
8
Comparison of hearing thresholds between the study and control groups shows that differences hearing thresholds reached levels of statistical significance at and above I2 kHz.
in their
M.S.
32
Rd.
V.K. Das/lnt.
J. Pediutr.
Otorhinolary@.
30 (1994)
29-40
Table 4 Comparison of right and left ears in each group (Mann-Whitney U-test, P-value) Frequency
8 IO I2 I4 I6 I8
Study group
Control group
0.9 0.6 0.6 0.1 0.8 0.8
1.0 0.5 0.9 0.2 0.4 0.5
The hearing threshold levels in the right ear was compared with the left ear in the study group. MannWhitney U-test demonstrated no difference between these ears, Similar findings were observed in the control group. Since there was statistically no difference (P = <0.05) between ears at any frequency for either group, the thresholds for the 2 ears were combined to derive the pure tone configurations shown for the two groups in (Table 3 and Fig. I).
All the equipment used in the study was regularly checked and calibrated throughout the study by a trained university audiology technician. An Amplaid 720 with XY plotter was used for tympanometry. 2.3. Procedure Testing was carried out in a sound treated room with the subject in a double walled sound proof booth. The tester and the equipment were outside the booth. Moditied Hughson Westlake Method of Limits [4] was used. Hearing thresholds above 8 kHz were determined in an ascending order at 2 kHz intervals. The order of presentation of the tone in the ears was varied to avoid practice effect [21] and headphones were also alternated.
Table 5 Comparison of high frequency hearing levels of same sex in both groups (Mann Whitney U-test result) Frequency (kHz)
8 IO I2 I4 I6 18
Males v. males (P-values)
Females v. females (P-values)
Right ear
Left ear
Right ear
Left ear
0.16 0.40 0.05 0.006 0.55 0.63
0.06 0.74 0.2 I 0.003 0.25 0.47
0.1 0.1 0.03 0.01 0.01 0.01
0.34 0.13 0.02 0.002 0.001 0.001
Comparison of hearing thresholds of males in both groups shows that in the study group it was worse at all the frequencies in both the ears, but they reached the level of significance at I2 kHz and 14 kHz in the right ear and at 14 kHz in the left ear. In the case of the females the differences in hearing levels reached a level of significance at and above I2 kHz in both the ears.
M.S. Ra-_i, V. K. Das /IN.
J. Pediutr.
Table 6 Mean and range of high frequency Frequency
(kHz) M
Otorhinolaryngol.
hearing
threshold
Range
30
( 19941 29-40
33
levels (dB SPL) Study group F
Range
f-values
Right ear 8
42.6
40-60
43.0
40-50
0.47
10 I2 I4 I6
42.6 38.2 56.5 58.8
40-55 30-80 40-l I5 35-l IO
45.5 46.0 63.5 71.0
0.09 II.03 lJ.IX 0.09
I8
84.7
55-115
99.5
40-55 30-65 45-85 45-105 60-I I5
40-55 40-55 30-65
0.09
0.04
Left ear 8
43.5
40-60
41.4
IO I2 I4 I6
42.9 39.1 53.5 61.2
35-55 30-95 40- I20 40-l IO
45.5 44.5 61.4 70.5
I8
83.5
55-l I5
103.2
0.16 0.05 0.03 0.05
45-80 50-85 75-l
0.006
I5
Comparison of right ear hearing thresholds between males and females in the study group shows that differences were statistically significant at I2 kHz and I8 kHz. In the left ear the differences reached a level of significance
at and above
I2 kHz.
3. Results
After eliminating those who did not fulfil the criteria of selection, 54 subjects aged 7-15 years were included in this study. Table 7 Mean and range of high frequency
hearing
threshold
levels (dB SPL) Control
group
Range
F
Range
P-values
40.9
40-50
41.3
35-50
0.79
lfl I6
40.9 32.7 44.5 53.2
40-45 30-35 40-55 35-75
42.7 37.3 48.7 47.3
40-55 30-55 40-70 35-75
0.33 0.09 0.44 0.17
I8
80.0
45-105
69.3
45-95
0.07
40.5 41.8 32.1 42.7 50.9 78.2
40-45 40-50 30-40 40-55 35-70 60-10
41.7 43.0 36.3 47.0 47.7 73.0
40-50 40-60 30-55 40-60 35-70 50-100
0.25 0.70 0.09 0.06 0.47 0.44
Frequency Right ear 8 IO I2
Left ear 8 IO I2 I4 I6 I8
(kHz)M
Comparison of right ears hearing thresholds between males and females in the control group shows that none of the differences reached a level of statistical significance. Similar findings were noted in the left ear.
34
M.S. Ruzi.
V.K. Das/Int.
J. Pediutr. Olorhinolur~ngoI. 30 (1994) 29-40
Table 8 Pure tone thresholds (dB SPL) of first test in 13 subjects Frequency (kHz)
8 10 I2 I4 I6 I8
Mean
Range
Right ear
Left ear
Right ear
Left ear
41.53 43.46 37.69 55.00 58.46 89.61
41.92 42.30 38.07 51.92 56.15 86.53
40-45 40-55 30-65 40-85 40-105 55-115
40-55 40-50 30-65 40-80 40-85 55-l I5
Overall 107 ears were tested and their tympanograms taken. None of the ears had hearing levels worse than 20 dBHL in the conventional frequency range. Similarly, none of the ears included had middle ear pressure outside the 0 to -110 mmH20 range. The right ear of one girl was not tested because of subtotal hearing loss. From the 54 subjects, 28 who had adverse perinatal factors comprised the ‘study group’ and the rest the ‘control group’. The mean age of the subjects in the study group was 11.39 years and in the control group 11.65 years. There were 17 males and 11 females in the study group with a mean age of 11.35 and 11.45 years, respectively. The control group consisted of 11 males and 15 females with a mean age of 12.3 years and 11.1 years, respectively. The differences in the number of subjects and their mean ages were statistically not significant. Six subjects in the study group did not respond at 18 kHz and were assigned a threshold of 5 dB above the maximum output of the audiometer at that frequency. Five of these subjects were females and one male. Five of these subjects had no response in either ear. One responded only in the right ear. One male subject did not respond in either ear.
Table 9 Pure tone thresholds (dB SPL) of retests in I3 subjects Frequency (kHz)
8 10 I2 I4 I6 I8
Range
Mean Right ear
Left ear
Right ear
Left ear
41.92 43.84 36.53 53.84 58.46 86.53
42.30 41.53 36.53 49.23 58.46 87.30
40-50 40-60 30-70 40-95 35-l 10 50-l IO
40-55 40-55 30-55 40-70 35-80 55-l IO
M.S.
Razi.
Table 10 Significance Frequency
P:K. Das/In~.
J. Pcdiutr.
levels for test-retest
Omhinolrry,gol.
result (Wilcoxon
(kHz)
35
30 i 19941 29-40
matched
pair test. P-value)
Right car
Left ear
8 IO
0.68 0.78
0.78 0.58
I2 I4 16 I8
0.47 0.72 0.95 0.13
0.26 0.056 0.16 0.51
Statistical analysis of test-retest values retested after a gap of 4-6 weeks,
shows
that
hearing
levels of children
remained
stable.
when
A study of Table 1 shows that the number of males and females varied in the problems mentioned. x2 test showed that these differences between sexes were statistically not significant except in the children who needed incubation. A history of postnatally acquired conditions like measles, mumps and ear problems was also obtained from both the groups (Table 2). None of these conditions reached a level of statistical significance between the groups. dB HL
-5 0
5 10 20 30 40 50 60 70 80 90 100 110
8
16 12 14 10 (FREQUENCY kHz)
18
o = Study Group x = Control Group Fig. I. Comparison
of high frequency
hearing
threshold
between
the study and control
groups.
36
M.S. Rari,
V.K. Das 1 lnt. J. Prdiutr. Otorl~inulur,w~ol. 30 (1994)
29-40
Thirteen children from the study group were randomly selected to determine their hearing thresholds between 4 and 6 weeks after the first test. The test-retest values and their range are presented in Tables 8 and 9. Wilcoxon’s matched pair test results (Table 10) demonstrated that high frequency hearing thresholds in these children remained stable after a gap of 4-6 weeks. 4. Discussion The effect of adverse perinatal events on conventional frequency are widely reported but there is very limited information on their effect on the high frequency hearing in children with adverse perinatal events. From the data presented (Table 3, Fig. l), it is clear that the high frequency hearing thresholds of the control group were better than for the study group at all the frequencies tested. The differences in the threshold reached a level of statistical significance at all the frequencies above 10 kHz. The difference was greatest at 18 kHz, which can be attributed to no responses at that frequency in 6 cases. The statistical difference in hearing threshold at some frequencies was maintained when high frequency hearing thresholds of males in the control group were compared with males
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 B
0 X
Fig. 2. Comparison
= =
right ear left ear
10 12 14 16 (FREQUENCY kHz)
l = A =
Males
of high frequency
hearing
threshold
18
right ear left ear
Females
between males and females in the study group.
M.S.
Razi.
C’.K. Das/Int.
J. Pediatr.
Otorhinolurwgol.
30 (1994)
,7Y-40
10 12 14 16 (FREQUENCY kHz)
18
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 8
0 X
= =
Fig. 3. Comparison
right ear left ear
l = A =
Males
of high frequency
hearing
threshold
right ear left ear
Females
between males and females in the control
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 8
10
12
14
(FREQUENCY 0 X
= =
right ear left ear
Fig. 4. Comparison
16 l
Study
= A =
Group
of high frequency
hearing
18
kHz)
threshold
right ear left ear
between
Control
Group
males in both groups.
group
M.S.
Razi.
V. K. DOS / hr.
J. Pediurr.
Otorhinolqwgol.
30 (1994)
29-40
dB HL
-5 0 5 10 20 30 40 50 60
70 80 90 100 110
I
1
8
0 X
= =
right ear left ear
L
10
I
L
12 14 18 (FREQUENCY kHz)
Study Group
l = A =
4
18
right ear left ear
Control
Group
Fig. 5. Comparison of high frequency hearing threshold between females in both the groups.
in the study group. These findings were more pronounced in females (Table 5, Fig. 2). This shows that both males and females in the study group suffered from high frequency hearing loss. Similar results were obtained, when high frequency hearing thresholds of males were compared with females in the study group (Table 6, Fig. 2). This is also supported by the result in Table 7, where comparison of hearing levels of males and females in the control group did not show any statistical difference. In the light of all these findings, females appear to have sustained much more damage than their male counterparts, suggesting that the high frequency hearing thresholds of females are more vulnerable to insult of perinatal events, which is contrary to the findings in the conventional frequency range where females appear to be more resistant to perinatal insults than male subjects. The statistical analysis carried out to determine the effect of each adverse perinatal event suggests that the effect of perinatal events on hearing sensitivity are complex and no single factor can be attributed to induce such damage. It is conceivable that perinatal factors cause high frequency hearing loss possibly by a synergistic effect of 2 or more adverse factors.
M.S. Razi. V.K. Das/Int.
J. Pediatr. Otorhinolarygol.
39
30 11994) 29-40
5. Conclusion It is concluded that adverse perinatal factors are directly associated with raising of high frequency hearing thresholds in children. There appears to be a synergistic effect of 2 or more adverse factors leading to the hearing loss in the frequency range from 12 kHz to 18 kHz. The aetiology and the site of lesion of high frequency hearing loss needs further investigation and a prospective study is needed to examine the interacting and potentiating effects which all these factors have on high frequency sensitivity. Further studies would be necessary to find out whether such subjects are more prone to hearing impairment in later life. The assessment of high frequency hearing in children may also help paediatricians and neonatologists in monitoring the efficacy and safety of various clinical techniques or procedures carried out in special care units for preterm babies in relation to hearing status.
6. Acknowledgements The authors wish to acknowledge the help given by Dr. V.E. Newton, Senior Lecturer and Honorary Consultant in Paediatric Audiological Medicine, Dr. V.F. Hillier, and the technical staff of the Centre for Audiology, Education of the Deaf and Speech Pathology, University of Manchester. in conducting this study. 7. References I
Bieter. R.C. and Rupp. R.R. (1972) Standard a normative study. J. Aud. Res. 12. 99-202.
audiometric
procedures
for thresholds
above X ~ kcs:
British Standards Institution (1980) Specifications for Audiometers. B.S. 5966. Brummett, R.E., Harris. R.F. and Lindgren. J.A. (1976) Detection of ototoxicity from drugs applied topically to the middle ear space. Laryngoscope 86. I l77- 1187. Carhart. R. and Jerger, J.F. (1959) Preferred method for clinical determination of puretone 5 6
thresholds. J. Speech Hear. Dis. 24, 330-345. Fausti. S.A., Erickson. D.A., Rappaport, B.Z.. Cleary, E.J. and Brummett, R.E. (1979) A system for evaluating auditory function from 8000-20 000 Hz. J. Acoustic Sot. Am. 66. 1713-1718. Fausti. S.A.. Erickson, D.A. and Rappaport. B.Z. (1981) The effect of noise upon human hearing sensitivity from 8000-20 000 Hz. J. Acoustic Sot. Am. 69(5). 1343- 1349. Fausti. S.A., Rappaport, B.Z. and Schechter. M.A. (1982) An investigation of the validity of high frequency audition. J. Acoustic Sot. Am. 71(3), 646-649. Fletcher, J.L.. Cairns, A.B.. Collins, F.G. and Endicott. J. (1967) High frequency hearing following meningitis. J. Aud. Res. 7, 223-227. Henry K.R. and Fast, G.A. (1984) Ultra high frequency auditory thresholds in young adults: rehable responses up to 24 kHz with a quasi-free field technique. Audiology 23, 477-489. International Electra-technical Commission (1970) Provisional Reference Coupler for the Calibration of Earphones used in Audiometry. I.E.C. Publication. 330. International Standard Organization (1975) The Value of Reference Equivalent Sound Pressure Level for Air Conduction. I.S.O. Recommendation. 389. Jacobson, E.J.. Downs, M.P. and Fletcher. J.L. (1969) Clinical findings in high frequency thresholds during known ototoxic drug usage. J. Aud. Res. 9, 379-385. Jerger, J.. Jerger. S. and Mauldin, L. (1972) Studies on impedance 513-523.
audiometry.
Arch.
Otol. 96,
40
14
I5 16 17 18 19 20 21
M.S.
Razi.
V. K. Das /ht.
J. Pdiatr.
Otorlkwlaryngol.
30 (1994)
29-40
McDermott, J.C., Fausti, S.A. and Frey, R.H. (1986) Effects of middle ear disease and cleft palate on high frequency hearing in children. Audiology 25, 136-148. Osterhammel, D., Osterhammel, P. and Terkildsenk (1977) A quasi-free field transducer system for high frequency audiometry. Stand. Audiol. 6, 91-95. Osterhammel, D., Osterhammel, P. and Terkildsenk (1977) high frequency thresholds using a quasifree field technique. &and. Audiol. 7. 27-30. Rappaport, B.Z., Fausti, S.A., Schechter, M.A. and Frey, H. (1982) Investigation of interaural attenuation factors for frequencies above 8000 Hz. J. Acoustic Sot. Am. 72(4). 1297-1298. Rosen, S.. Plester, D., Mofty, A.E. and Rosen, H.V. (1964) High frequency audiometry in presbycusis. Arch. Otol. 79, 34-47. Rosen S. and Olin, P. (1965) Hearing loss and coronary heart disease. Arch. Otol. 82, 236-243. Tandorff, J. (1985) High frequency audiometry. Seminar in hearing electro-stimulation, pp. 359-367. Cited by Goldstein et al. (1987). Zislis, T. and Fletcher, J.L. (1966) Relation of high frequency thresholds to age and sex. J. Aud. Res. 6, 189-196.
OF
Pediatric
International
ELSEWER SClENCF lRFL.AND
Journal
of Pediatric Otorhinolaryngology
30 (1994) 29-40
Effects of adverse perinatal events on hearing M.S. Razi. V.K. Das*
(Received
I? July 1993; revision received I3 December
1993; accepted 19 December
1993)
Abstract The hearing sensitivity for frequencies 8 kHz through to 18 kHz was compared between children with adverse perinatal factors (study group) and children without adverse perinatal factors (control group). Children in both groups had hearing at levels of 20 dB HL or better in the frequency range between 250 Hz to 8 kHz with normal middle ear pressure. High frequency hearing tests showed that the mean high frequency hearing threshold levels were worse in the study group. Statistical analysis showed significant differences in hearing levels at and above 12 kHz frequencies between the study and control groups. The hearing levels were found to be more significantly affected in females as compared to males, indicating that the high frequency hearing of females was more vulnerable to damage. The results indicate that adverse perinatal events are associated with raised high frequency thresholds in both sexes, especially in females. KeJ words: Preterm birth; Adverse perinatal factors: High frequency hearing thresholds; Sensorineural hearing loss
1. Introduction The human physiological upper frequency limit of hearing has always been a focus of interest to Psychologists and Speech Pathologists. Audiologists have often expressed the clinical opinion that high frequency hearing loss may be a precursor of auditory disorder. The routine pure tone assessment normally is restricted to the range of 250 Hz to 8 kHz, possibly because most of the important sounds of speech and everyday life fall within this range. * Corresponding
Ol65-5876/94/$07.00 SSDI
author
0
1994 Elsevier Science Ireland
0165-5876(94)01012-M
Ltd. All rights reserved
M.S. Rozi. V.K. Das/Inr.
30
J. Pediutr. Otorlhwlur~ngoi.
30 (1994) 29-40
Rosen et al. (1964) [ 181introduced high frequency audiometry to clinical studies. The larger number of studies in the last 30 years is due to the recognition of the greater susceptibility of the basal part of the cochlea for both acquired and inherited sensorineural disease process. It is now recognized that high frequency hearing levels are most vulnerable to noxious influences than are the traditional test frequencies below 8 kHz [3,5,6,8.12,19,21]. The instruments employed in the majority of high frequency audiometric studies have provided air conduction measurements up to 20-24 kHz. The techniques have varied from Quasi free field method [9,16] to the use of special high frequency headphones [5,14,17]. The availability of Demlar 20 K high frequency audiometers and the introduction of electric bone conduction audiometry are useful additions to high frequency audiometry [20]. 2. Materials and methods 2.1. Methodology
Children aged between 7 and 15 years with hearing thresholds 5 20 dB HL [l l] and middle ear pressure between 0 to -100 mmHzO [ 131 were selected for this study. The study group was composed of children with one or more of the following adverse perinatal factors: prematurity, low birth weight, asphyxia, apnoea, respiratory distress syndrome, hyperbilirubinaemia, meningitis, incubator care, ototoxic medi-
Table I Perinatal
problems Study group
I. 2.
Premature Low birth weight
3.
(a) Below 1500 g (b) Between 1501-2500 (c) Above 2500 g Small for date
4. 5. 6. 7.
Hypoxia Respiratory Apnoea Incubation
8. 9. 10.
distress
g
syndrome
Jaundice Birth trauma Mode of delivery: (a) N.V.D.
(n = 28)
M
F
7 5
8
2 3 I2 3 4 I I 3
I 6 4 4
10
3 0
I
N.V.D.,
normal
(n = 26)
M
F
II
I5
5 4 I I vertex delivery;
group
2 I I 7
(b) Forceps (c) C.Sec. (elective) (d) C.Sec. (emergency) Abbreviations:
Control
C.Sec., Ceasarean
section.
14 I 0 0
M.S.
Ra:i.
Table 2 Postnatal
V. K. Das / Int. J. Pediatr.
Otorhinolaryngol.
30
i 1994 i
29-40
problems Study group
Control
group
M
F
M
F
Measles Mumps
9 IO
6 3
5 4
6 6
Measles and mumps No measles or mumps Recurrent ear infections
6 4 I4
2 4 6
2 3 6
4 x II
cation. All the study children had normal hearing in the frequency range of 250 Hz to 8 kHz. Children who had none of the problems mentioned above served as controls. Children with a history of cleft palate, repaired cleft palate, middle ear surgery or presence of congenital or longstanding middle ear dysfunction at the time of the study were excluded. 2.2. Instruments The Peters AP5 with TDH-39 headphone in MX-41 ear cushion was used for testing hearing between 250 and 8000 Hz. The audiometer was calibrated to B.S. 5966 [2]. The output of the headphone was checked as per specification of IEC-303 [lo]. For testing hearing between 8- 18 kHz, the Peters AP5 audiometer with some alteration was used. Beyer Dynamic DT-48 headphones were used. The maximum output of the audiometer ranged between 110-120.5 dB SPL through 8-18 kHz. The dial reading of -10 dB was equal to 40 dB SPL for 8 kHz, 10 kHz and 14 kHz, 30 dB SPL for 12 kHz and 18 kHz and 35 dB SPL for 16 kHz.
Table 3 Mean high frequency Frequency
hearing
threshold
levels (dB SPL) group
(n = 26)
P-value
Study group ‘(n = 28)
Control
Mean
Range
Mean
Range
10
42.8 43.9
40.0-60.0 37.5-52.5
41.1 42.2
40.0-50.0 40.0-52.5
0.09 0.22
I? I4 I6 18
41.4 51.9 64.2 91.0
30.0-87.5 40.0-l 17.5 40.0-I 10.0 57.5-l 15.0
35. I 46. I 49.4 74.5
30.0-55.0 40.0-60.0 35.0-72.5 47.5-97.5
0.03 0.01 0.0 I 0.01
(kHe)
8
Comparison of hearing thresholds between the study and control groups shows that differences hearing thresholds reached levels of statistical significance at and above I2 kHz.
in their
M.S.
32
Rd.
V.K. Das/lnt.
J. Pediutr.
Otorhinolary@.
30 (1994)
29-40
Table 4 Comparison of right and left ears in each group (Mann-Whitney U-test, P-value) Frequency
8 IO I2 I4 I6 I8
Study group
Control group
0.9 0.6 0.6 0.1 0.8 0.8
1.0 0.5 0.9 0.2 0.4 0.5
The hearing threshold levels in the right ear was compared with the left ear in the study group. MannWhitney U-test demonstrated no difference between these ears, Similar findings were observed in the control group. Since there was statistically no difference (P = <0.05) between ears at any frequency for either group, the thresholds for the 2 ears were combined to derive the pure tone configurations shown for the two groups in (Table 3 and Fig. I).
All the equipment used in the study was regularly checked and calibrated throughout the study by a trained university audiology technician. An Amplaid 720 with XY plotter was used for tympanometry. 2.3. Procedure Testing was carried out in a sound treated room with the subject in a double walled sound proof booth. The tester and the equipment were outside the booth. Moditied Hughson Westlake Method of Limits [4] was used. Hearing thresholds above 8 kHz were determined in an ascending order at 2 kHz intervals. The order of presentation of the tone in the ears was varied to avoid practice effect [21] and headphones were also alternated.
Table 5 Comparison of high frequency hearing levels of same sex in both groups (Mann Whitney U-test result) Frequency (kHz)
8 IO I2 I4 I6 18
Males v. males (P-values)
Females v. females (P-values)
Right ear
Left ear
Right ear
Left ear
0.16 0.40 0.05 0.006 0.55 0.63
0.06 0.74 0.2 I 0.003 0.25 0.47
0.1 0.1 0.03 0.01 0.01 0.01
0.34 0.13 0.02 0.002 0.001 0.001
Comparison of hearing thresholds of males in both groups shows that in the study group it was worse at all the frequencies in both the ears, but they reached the level of significance at I2 kHz and 14 kHz in the right ear and at 14 kHz in the left ear. In the case of the females the differences in hearing levels reached a level of significance at and above I2 kHz in both the ears.
M.S. Ra-_i, V. K. Das /IN.
J. Pediutr.
Table 6 Mean and range of high frequency Frequency
(kHz) M
Otorhinolaryngol.
hearing
threshold
Range
30
( 19941 29-40
33
levels (dB SPL) Study group F
Range
f-values
Right ear 8
42.6
40-60
43.0
40-50
0.47
10 I2 I4 I6
42.6 38.2 56.5 58.8
40-55 30-80 40-l I5 35-l IO
45.5 46.0 63.5 71.0
0.09 II.03 lJ.IX 0.09
I8
84.7
55-115
99.5
40-55 30-65 45-85 45-105 60-I I5
40-55 40-55 30-65
0.09
0.04
Left ear 8
43.5
40-60
41.4
IO I2 I4 I6
42.9 39.1 53.5 61.2
35-55 30-95 40- I20 40-l IO
45.5 44.5 61.4 70.5
I8
83.5
55-l I5
103.2
0.16 0.05 0.03 0.05
45-80 50-85 75-l
0.006
I5
Comparison of right ear hearing thresholds between males and females in the study group shows that differences were statistically significant at I2 kHz and I8 kHz. In the left ear the differences reached a level of significance
at and above
I2 kHz.
3. Results
After eliminating those who did not fulfil the criteria of selection, 54 subjects aged 7-15 years were included in this study. Table 7 Mean and range of high frequency
hearing
threshold
levels (dB SPL) Control
group
Range
F
Range
P-values
40.9
40-50
41.3
35-50
0.79
lfl I6
40.9 32.7 44.5 53.2
40-45 30-35 40-55 35-75
42.7 37.3 48.7 47.3
40-55 30-55 40-70 35-75
0.33 0.09 0.44 0.17
I8
80.0
45-105
69.3
45-95
0.07
40.5 41.8 32.1 42.7 50.9 78.2
40-45 40-50 30-40 40-55 35-70 60-10
41.7 43.0 36.3 47.0 47.7 73.0
40-50 40-60 30-55 40-60 35-70 50-100
0.25 0.70 0.09 0.06 0.47 0.44
Frequency Right ear 8 IO I2
Left ear 8 IO I2 I4 I6 I8
(kHz)M
Comparison of right ears hearing thresholds between males and females in the control group shows that none of the differences reached a level of statistical significance. Similar findings were noted in the left ear.
34
M.S. Ruzi.
V.K. Das/Int.
J. Pediutr. Olorhinolur~ngoI. 30 (1994) 29-40
Table 8 Pure tone thresholds (dB SPL) of first test in 13 subjects Frequency (kHz)
8 10 I2 I4 I6 I8
Mean
Range
Right ear
Left ear
Right ear
Left ear
41.53 43.46 37.69 55.00 58.46 89.61
41.92 42.30 38.07 51.92 56.15 86.53
40-45 40-55 30-65 40-85 40-105 55-115
40-55 40-50 30-65 40-80 40-85 55-l I5
Overall 107 ears were tested and their tympanograms taken. None of the ears had hearing levels worse than 20 dBHL in the conventional frequency range. Similarly, none of the ears included had middle ear pressure outside the 0 to -110 mmH20 range. The right ear of one girl was not tested because of subtotal hearing loss. From the 54 subjects, 28 who had adverse perinatal factors comprised the ‘study group’ and the rest the ‘control group’. The mean age of the subjects in the study group was 11.39 years and in the control group 11.65 years. There were 17 males and 11 females in the study group with a mean age of 11.35 and 11.45 years, respectively. The control group consisted of 11 males and 15 females with a mean age of 12.3 years and 11.1 years, respectively. The differences in the number of subjects and their mean ages were statistically not significant. Six subjects in the study group did not respond at 18 kHz and were assigned a threshold of 5 dB above the maximum output of the audiometer at that frequency. Five of these subjects were females and one male. Five of these subjects had no response in either ear. One responded only in the right ear. One male subject did not respond in either ear.
Table 9 Pure tone thresholds (dB SPL) of retests in I3 subjects Frequency (kHz)
8 10 I2 I4 I6 I8
Range
Mean Right ear
Left ear
Right ear
Left ear
41.92 43.84 36.53 53.84 58.46 86.53
42.30 41.53 36.53 49.23 58.46 87.30
40-50 40-60 30-70 40-95 35-l 10 50-l IO
40-55 40-55 30-55 40-70 35-80 55-l IO
M.S.
Razi.
Table 10 Significance Frequency
P:K. Das/In~.
J. Pcdiutr.
levels for test-retest
Omhinolrry,gol.
result (Wilcoxon
(kHz)
35
30 i 19941 29-40
matched
pair test. P-value)
Right car
Left ear
8 IO
0.68 0.78
0.78 0.58
I2 I4 16 I8
0.47 0.72 0.95 0.13
0.26 0.056 0.16 0.51
Statistical analysis of test-retest values retested after a gap of 4-6 weeks,
shows
that
hearing
levels of children
remained
stable.
when
A study of Table 1 shows that the number of males and females varied in the problems mentioned. x2 test showed that these differences between sexes were statistically not significant except in the children who needed incubation. A history of postnatally acquired conditions like measles, mumps and ear problems was also obtained from both the groups (Table 2). None of these conditions reached a level of statistical significance between the groups. dB HL
-5 0
5 10 20 30 40 50 60 70 80 90 100 110
8
16 12 14 10 (FREQUENCY kHz)
18
o = Study Group x = Control Group Fig. I. Comparison
of high frequency
hearing
threshold
between
the study and control
groups.
36
M.S. Rari,
V.K. Das 1 lnt. J. Prdiutr. Otorl~inulur,w~ol. 30 (1994)
29-40
Thirteen children from the study group were randomly selected to determine their hearing thresholds between 4 and 6 weeks after the first test. The test-retest values and their range are presented in Tables 8 and 9. Wilcoxon’s matched pair test results (Table 10) demonstrated that high frequency hearing thresholds in these children remained stable after a gap of 4-6 weeks. 4. Discussion The effect of adverse perinatal events on conventional frequency are widely reported but there is very limited information on their effect on the high frequency hearing in children with adverse perinatal events. From the data presented (Table 3, Fig. l), it is clear that the high frequency hearing thresholds of the control group were better than for the study group at all the frequencies tested. The differences in the threshold reached a level of statistical significance at all the frequencies above 10 kHz. The difference was greatest at 18 kHz, which can be attributed to no responses at that frequency in 6 cases. The statistical difference in hearing threshold at some frequencies was maintained when high frequency hearing thresholds of males in the control group were compared with males
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 B
0 X
Fig. 2. Comparison
= =
right ear left ear
10 12 14 16 (FREQUENCY kHz)
l = A =
Males
of high frequency
hearing
threshold
18
right ear left ear
Females
between males and females in the study group.
M.S.
Razi.
C’.K. Das/Int.
J. Pediatr.
Otorhinolurwgol.
30 (1994)
,7Y-40
10 12 14 16 (FREQUENCY kHz)
18
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 8
0 X
= =
Fig. 3. Comparison
right ear left ear
l = A =
Males
of high frequency
hearing
threshold
right ear left ear
Females
between males and females in the control
dB HL
-5 0 5 10 20 30 40 50 60 70 80 90 100 110 8
10
12
14
(FREQUENCY 0 X
= =
right ear left ear
Fig. 4. Comparison
16 l
Study
= A =
Group
of high frequency
hearing
18
kHz)
threshold
right ear left ear
between
Control
Group
males in both groups.
group
M.S.
Razi.
V. K. DOS / hr.
J. Pediurr.
Otorhinolqwgol.
30 (1994)
29-40
dB HL
-5 0 5 10 20 30 40 50 60
70 80 90 100 110
I
1
8
0 X
= =
right ear left ear
L
10
I
L
12 14 18 (FREQUENCY kHz)
Study Group
l = A =
4
18
right ear left ear
Control
Group
Fig. 5. Comparison of high frequency hearing threshold between females in both the groups.
in the study group. These findings were more pronounced in females (Table 5, Fig. 2). This shows that both males and females in the study group suffered from high frequency hearing loss. Similar results were obtained, when high frequency hearing thresholds of males were compared with females in the study group (Table 6, Fig. 2). This is also supported by the result in Table 7, where comparison of hearing levels of males and females in the control group did not show any statistical difference. In the light of all these findings, females appear to have sustained much more damage than their male counterparts, suggesting that the high frequency hearing thresholds of females are more vulnerable to insult of perinatal events, which is contrary to the findings in the conventional frequency range where females appear to be more resistant to perinatal insults than male subjects. The statistical analysis carried out to determine the effect of each adverse perinatal event suggests that the effect of perinatal events on hearing sensitivity are complex and no single factor can be attributed to induce such damage. It is conceivable that perinatal factors cause high frequency hearing loss possibly by a synergistic effect of 2 or more adverse factors.
M.S. Razi. V.K. Das/Int.
J. Pediatr. Otorhinolarygol.
39
30 11994) 29-40
5. Conclusion It is concluded that adverse perinatal factors are directly associated with raising of high frequency hearing thresholds in children. There appears to be a synergistic effect of 2 or more adverse factors leading to the hearing loss in the frequency range from 12 kHz to 18 kHz. The aetiology and the site of lesion of high frequency hearing loss needs further investigation and a prospective study is needed to examine the interacting and potentiating effects which all these factors have on high frequency sensitivity. Further studies would be necessary to find out whether such subjects are more prone to hearing impairment in later life. The assessment of high frequency hearing in children may also help paediatricians and neonatologists in monitoring the efficacy and safety of various clinical techniques or procedures carried out in special care units for preterm babies in relation to hearing status.
6. Acknowledgements The authors wish to acknowledge the help given by Dr. V.E. Newton, Senior Lecturer and Honorary Consultant in Paediatric Audiological Medicine, Dr. V.F. Hillier, and the technical staff of the Centre for Audiology, Education of the Deaf and Speech Pathology, University of Manchester. in conducting this study. 7. References I
Bieter. R.C. and Rupp. R.R. (1972) Standard a normative study. J. Aud. Res. 12. 99-202.
audiometric
procedures
for thresholds
above X ~ kcs:
British Standards Institution (1980) Specifications for Audiometers. B.S. 5966. Brummett, R.E., Harris. R.F. and Lindgren. J.A. (1976) Detection of ototoxicity from drugs applied topically to the middle ear space. Laryngoscope 86. I l77- 1187. Carhart. R. and Jerger, J.F. (1959) Preferred method for clinical determination of puretone 5 6
thresholds. J. Speech Hear. Dis. 24, 330-345. Fausti. S.A., Erickson. D.A., Rappaport, B.Z.. Cleary, E.J. and Brummett, R.E. (1979) A system for evaluating auditory function from 8000-20 000 Hz. J. Acoustic Sot. Am. 66. 1713-1718. Fausti. S.A.. Erickson, D.A. and Rappaport. B.Z. (1981) The effect of noise upon human hearing sensitivity from 8000-20 000 Hz. J. Acoustic Sot. Am. 69(5). 1343- 1349. Fausti. S.A., Rappaport, B.Z. and Schechter. M.A. (1982) An investigation of the validity of high frequency audition. J. Acoustic Sot. Am. 71(3), 646-649. Fletcher, J.L.. Cairns, A.B.. Collins, F.G. and Endicott. J. (1967) High frequency hearing following meningitis. J. Aud. Res. 7, 223-227. Henry K.R. and Fast, G.A. (1984) Ultra high frequency auditory thresholds in young adults: rehable responses up to 24 kHz with a quasi-free field technique. Audiology 23, 477-489. International Electra-technical Commission (1970) Provisional Reference Coupler for the Calibration of Earphones used in Audiometry. I.E.C. Publication. 330. International Standard Organization (1975) The Value of Reference Equivalent Sound Pressure Level for Air Conduction. I.S.O. Recommendation. 389. Jacobson, E.J.. Downs, M.P. and Fletcher. J.L. (1969) Clinical findings in high frequency thresholds during known ototoxic drug usage. J. Aud. Res. 9, 379-385. Jerger, J.. Jerger. S. and Mauldin, L. (1972) Studies on impedance 513-523.
audiometry.
Arch.
Otol. 96,
40
14
I5 16 17 18 19 20 21
M.S.
Razi.
V. K. Das /ht.
J. Pdiatr.
Otorlkwlaryngol.
30 (1994)
29-40
McDermott, J.C., Fausti, S.A. and Frey, R.H. (1986) Effects of middle ear disease and cleft palate on high frequency hearing in children. Audiology 25, 136-148. Osterhammel, D., Osterhammel, P. and Terkildsenk (1977) A quasi-free field transducer system for high frequency audiometry. Stand. Audiol. 6, 91-95. Osterhammel, D., Osterhammel, P. and Terkildsenk (1977) high frequency thresholds using a quasifree field technique. &and. Audiol. 7. 27-30. Rappaport, B.Z., Fausti, S.A., Schechter, M.A. and Frey, H. (1982) Investigation of interaural attenuation factors for frequencies above 8000 Hz. J. Acoustic Sot. Am. 72(4). 1297-1298. Rosen, S.. Plester, D., Mofty, A.E. and Rosen, H.V. (1964) High frequency audiometry in presbycusis. Arch. Otol. 79, 34-47. Rosen S. and Olin, P. (1965) Hearing loss and coronary heart disease. Arch. Otol. 82, 236-243. Tandorff, J. (1985) High frequency audiometry. Seminar in hearing electro-stimulation, pp. 359-367. Cited by Goldstein et al. (1987). Zislis, T. and Fletcher, J.L. (1966) Relation of high frequency thresholds to age and sex. J. Aud. Res. 6, 189-196.