Eur J Pediatr (2006) 165:851–857 DOI 10.1007/s00431-006-0181-5
ORIGINAL PAPER
Parental suspicion of hearing loss in children with otitis media with effusion Phoebe S. Y. Lo & Michael C. F. Tong & Eric M. C. Wong & C. Andrew van Hasselt
Received: 8 December 2005 / Revised: 5 May 2006 / Accepted: 9 May 2006 / Published online: 22 July 2006 # Springer-Verlag 2006
Abstract Objective This study aimed to evaluate the parental suspicion of hearing loss in children with otitis media with effusion (OME). As part of a population-based survey in a screening programme among 6- to 7-year-old Chinese children in Hong Kong, OME cases and controls were studied for the value of parental observations in the prediction of OME and hearing test results. Subjects and methods Prior to the otoscopic and tympanometric examination of the children on school premises, a self-administered binary-choice question was sent to the parents asking whether there was any suspicion of hearing impairment. Positive screens and randomly selected negative screens were seen in a hospital clinic for the confirmation of case and control status 2 to 3 weeks after the school screening. Aural examination under microscopy, repeated tympanometry and stapedial reflex testing, and pure-tone audiometry (PTA) were conducted, and 117 cases and 159 controls were included in this study. Results The average PTA conductive threshold levels in the individual children with OME ranged from 3.8 dB to 40.0 dB with a group mean of 17.0 dB in the better-hearing ears. Parental suspicion of hearing deficit was significantly associated with OME (p<0.001) but not PTA findings
P. S. Y. Lo (*) : M. C. F. Tong : C. A. van Hasselt Division of Otorhinolaryngology, Department of Surgery and Institute of Human Communicative Research, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong SAR, People’s Republic of China e-mail:
[email protected] E. M. C. Wong Centre for Epidemiology and Biostatistics, School of Public Health, The Chinese University of Hong Kong, Hong Kong SAR, People’s Republic of China
(p=0.686). The sensitivity of parent-suspected hearing impairment to detect OME however was very low (19.7%). Discussion In other words, if we had relied on parental suspicion as the first screening, at least 80% of the OME cases would have been missed. We conclude that the parental suspicion of hearing loss is inadequate for the identification of mild hearing loss as caused by OME. Health education is recommended to improve parental awareness of the disease. Keywords Children . Hearing loss . Otitis media with effusion . Parental suspicion . Sensitivity and specificity Abbreviations MEE Middle ear effusion OME Otitis media with effusion PPV Positive predictive value PTA Pure-tone audiometry NPV Negative predictive value
Introduction Otitis media with effusion (OME) refers to the condition in which bodily fluid accumulates in the middle ear cavity behind an intact tympanic membrane. The disease is prevalent in children, with higher rates in the younger age groups. Middle ear effusion (MEE) often resolves spontaneously without any treatment, but, occasionally, it persists, resulting in mild or moderate conductive hearing loss [1, 8, 25]. Children with untreated chronic OME are also at risk of permanent damage to the middle ear structures, such as causing myringosclerosis or ossicular chain disruption. There is controversy as to whether repeated episodes of hearing impairment will affect behaviour or speech devel-
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opment in early childhood or academic performance in schoolchildren [3, 5, 18, 22]. According to the management guideline from the Agency for Health Care Policy and Research, audiometric evaluation is recommended for children with persistent OME for three months or longer or at any time that a hearing loss is suspected [1]. Myringotomy with tympanostomy tube placement may be considered if OME persists for more than three months and is combined with hearing impairment. Clinical signs and symptoms of OME are not remarkable. In most cases, the disease is unexpectedly picked up by primary care physicians at clinical examination for acute upper respiratory tract infection or related diseases [12]. OME is often diagnosed late and problems are left unattended [7]. Parents or caregivers who are in close contact with the child are supposed to understand the child well. Does the associated hearing deficit generate a warning signal to the parents? Existing information regarding the OME-related parent-perceived hearing loss was scant and study samples were mostly limited to very young children. In a caregiver survey by means of a newly developed questionnaire, Brody et al. [4] concluded that parents were not capable of detecting mild hearing loss in their child. In a study of OME children with a median age of two years, Stewart et al. [19] reported that parent-perceived hearing loss correlated very poorly with audiometric results both before and after surgery. In following the infants from birth until the age of two years, Engel et al. [9] found that parent-reported hearing loss was of minimal value in the discrimination of OME. These studies investigated the quantitative parental judgment in association with either the clinically diagnosed OME or objective hearing test results, but did not further analyse parental comments on the child’s hearing status. Moreover, it is not certain whether similar outcomes could be expected from the parents with relatively older children. The present study aimed to answer this question with supportive evidence from a case–control study in Hong Kong. In the study, we examined the value of parent-suspected hearing loss in the prediction of OME and pure-tone audiometric (PTA) threshold levels in the children. Textual statements from the parents in regard to their impressions on the child’s hearing status were examined.
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the literature [20, 21]. The present paper, as part of the prospective study, focusses on the children’s hearing levels and parental judgment that have not been reported on before. The method for OME screening and diagnosis is briefly described here. Prior to the screening for the presence of middle ear pathologies, a self-administered medical history questionnaire was sent through the schools to the parents. In addition, a binary-choice question was made asking whether or not there was a suspicion of hearing impairment in the child. Free text space was provided for the parents to write down their impressions and comments on the child’s hearing status. On the school premises, an otolaryngologist and an audiologist performed otoscopic and tympanometric examinations, respectively, on the children. Children with (1) otoscopic appearance of effusion/bubble or (2) an abnormal type B or type C tympanogram with no stapedial reflex presentation were referred as positive screens for follow-up. Table 1 describes the tympanogram types as defined by Fiellau-Nikolajsen and Lous [10]. Schoolchildren who passed the screening tests were regarded as negative screens and were randomly selected for follow-up. Both positive and negative screens were invited to attend a Specialist Ear Clinic two to three weeks after the school screening. They were examined with comparable procedures, including a detailed medical history, aural examination under microscopy, repeated tympanometry and stapedial reflex testing, and standard PTA. In total, 446 children (97%) attended the clinic. On examination, children with positive screens exhibiting an effusion on microscopy or an abnormal tympanometry (identified with the use of the Cantekin algorithm [6]) with an average air-bone gap of 10 dB in at least one of the ears were diagnosed as chronic OME and were included as the case subjects in this study. Children with normal tympanic appearance and type A tympanogram both at school and at the clinic were employed as controls. Inclusion criteria for enrolment in this study were case and control subjects (1) with parental consent, (2) with parental response to the questionnaire (99.3%), (3) of Chinese descendants, (4) 6 to 7 years of age and (5) with PTA results. Exclusion criteria were children (1) with previous history of ear surgery, (2) with craniofacial anomalies like cleft palate, (3) with sensory deficit or (4) with a known Table 1 Classification of tympanometry types
Subjects and methods This test was a nested case–control study drawn from a population-based OME screening survey of 5,898 primaryone schoolchildren in Hong Kong. The study was approved by the Ethical Committee of The Chinese University of Hong Kong. The methodology, parental consent and results of OME prevalence rates and risk factors were published in
Tympanogram
Type
Middle ear pressure
Description of the pressure (daPa)
Peaked
A C1 C2 B
Normal Negative Negative Negative
200 to −99 −100 to −199 −200 to −400 indeterminable
Non-peaked/ flat curve
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history of OME before the school screening. Eight cases (2.7%) were excluded from the analysis due to known OME with previous treatment. As a consequence, 117 cases (40.2% unilateral, 59.8% bilateral) and 159 controls were included in the current analysis (total n=276). Statistical analysis PTA findings from the better-hearing ears were analysed as the estimate of hearing attainment in daily living. To define the degree of hearing loss, PTA threshold averages were graded according to Northern and Downs’ classification [14], as displayed in Table 2. To facilitate dichotomous analysis, PTA parameters were categorised into two groups with a cut-off point at 25 dB on the average hearing threshold levels at 500, 1,000, 2,000 and 4,000 Hz. Chisquare test or Fisher’s exact test was applied to examine the association between parental suspicion of hearing loss and clinically diagnosed OME and also PTA results. An independent t test was used to compare the significant difference in the average hearing thresholds between the parent-suspected and non-suspected groups. Unless stated otherwise, analyses on the hearing test used air-conductive threshold data of the better-hearing ears. The frequencies of the dichotomous parental responses were tabulated according to the OME cases and controls to form the 2×2 contingency table. Similarly, a contingency table was created for the parental responses according to the two-tier PTA threshold groups. To investigate the predictive value of the parental suspicion of hearing loss, sensitivity, specificity, positive and negative predictive values were calculated. The association between the parental responses and educational levels was tested with Chi-square or Fisher’s exact test. Significance levels were set at p<0.05.
Table 2 Number of ears in the classification of average conductive hearing threshold levels with the better-hearing ears of the children with and without middle ear effusion (MEE) Average threshold level Description at 500–2000 Hz*
Better-hearing ears Children Children with MEE without MEE
0–15 dB 16–25 dB 26–40 dB 41–65 dB 66–95 dB 96+ dB Total
Normal range Slight hearing loss Mild hearing loss Moderate hearing loss Severe hearing loss Profound hearing loss
60 41 16 0 0 0 117
136 22 1 0 0 0 159
*Based on Northern and Downs’ classification of hearing threshold levels [14]
Results There were 69 boys and 48 girls in the OME group (n=117), and 91 boys and 68 girls in the control group (n=159). In total, 10% (n=28) of the parents reported a suspicion of hearing loss in their child, and 43% (n=12) of these parents provided further written information in relation to the child’s hearing status. Audiological results in the case and control subjects Table 2 demonstrates the frequency distribution of the average air-conductive threshold levels in the better-hearing ears of the children with and without MEE. Fourteen percent (n=16) of the children with OME were classified as having mild hearing loss and none were regarded as moderate loss or poorer. The average PTA conductive hearing threshold level in the entire case group was 17.0 dB (range 3.8–40.0 dB) in the better-hearing ears. The mean of both ears in the individuals ranged from 7.5 dB to 40.6 dB. Around 60% (n=70) of the case subjects were found to have bilateral MEE with relatively poorer hearing thresholds (better-hearing ears: M=19.7 dB, SD=6.4) than the unilateral OME subjects (better-hearing ears: M=13.1 dB, SD=3.8) (p<0.001). The average air-conductive threshold levels in the control subjects were within normal limits for both ears (better-hearing ears: M=11.9 dB, SD=4.2). The bone-conduction threshold levels for both case subjects (better-hearing ears: M=4.9 dB, SD=4.0) and control subjects (better-hearing ears: M=8.2 dB, SD=4.2) were of normal ranges. Parental responses Although there was a higher percentage of parental suspicion of hearing impairment in the children with MEE (n=23) than those without MEE (n=5), many parents (n=94) in the OME group did not perceive a hearing problem (Table 3). The majority of parents (96.9%, n=154) in the control group were able to verify normal hearing in their child. Parental suspicion was significantly associated with OME (p<0.001). The sensitivity of parent-suspected hearing loss to detect OME however was very low (19.7%), although a positive predictive value (PPV) of 82.1% was acceptable. There was a high specificity (96.9%). The negative predictive value (NPV) was of moderate effect (62.1%). There were no significant differences in the education background between the parents who suspected and who did not suspect a hearing deficit in their child both for the OME group (p=0.336) and the entire group (p=0.159). Figure 1 shows the mean conductive hearing thresholds of both ears at various frequencies between the parent-
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Table 3 Parental responses versus children with and without middle ear effusion (MEE) for the calculation of sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively)
Parental suspicion of hearing loss (n=28) Parental perception of no hearing loss (n=248)
Children with MEE (n=117)
Children without MEE (n=159)
23 94 Sensitivity 19.7%
5 154 Specificity 96.9%
tion, all of the mentioned children (n=12) were found to have OME except for one subject with impacted earwax. Eight (73%) out of the children with OME (n=11) were found to have bilateral pathology. The child with a suspicion of left hearing loss by the parent also had bilateral OME.
suspected (n=28) and non-suspected hearing loss (n=248) groups. There were significant differences in the hearing levels between the two distinct groups (p=0.001 for both ears; p=0.019 for the better-hearing ears). In OME cases only, there was no significant difference in the average PTA results between the parental suspicion and non-suspicion groups (p=0.750). Among all of the examined subjects, 17 children (6.2%) were found to have an average conductive hearing threshold worse than 25 dB in their better-hearing ears. Of these children, 88% (n=15) of the parents had no insight into the hearing impairment (Table 4). On examination, 16 out of these 17 children were found to have OME (15 bilateral and 1 unilateral) and the other child was a control subject with excessive impacted earwax in both ears. No association was detected between parental suspicion and PTA findings using data from the better-hearing ears (p=0.686). The sensitivity of parental suspicion to estimate PTA thresholds was very low (11.8%), with a poor PPV of 7.1%. On the contrary, the specificity was high (90.0%), with an NPV of 94.0%. Written reports from parents (n=12) are shown in Table 5. Many parents seemed to describe the condition reflecting a hearing difficulty either through observations in daily activities or direct responses from the child. On examina-
Discussion Our study results showed that, in general, the hearing deficit caused by OME was minor. Using 25 dB average hearing level as the cut-off point between normal and abnormal hearing in the better-hearing ears for daily communication, the point-prevalent rate of hearing loss in 6- to 7-year-old Chinese children with OME was low (14%) and the degree was mild. Subjects with bilateral OME presented the highest conductive hearing threshold levels that indicated the worst hearing status among all of the children. This finding was coherent with Sabo et al.’s study result [16] that children with bilateral MEE had poorer hearing acuity than the unilateral subjects. In a Dutch study of 7.5- to 8-year-olds, 4% of the OME children were found to have a PTA average level ≥15 dB in the better-hearing
30
Hearing level d dB B
25
20
15
Parental suspicion hearing loss group
10
4000 Hz
2000 Hz
1000 Hz
500 Hz
5
0
PPV 82.1% NPV 62.1%
Frequency Fig. 1 Mean conductive thresholds of both ears at each frequency of the pure-tone audiometry (PTA)
Parent perceived no hearing loss group
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Table 4 Parental responses versus the children with a cutpoint of 25 dB in the average conductive hearing thresholds in the better-hearing ears for the calculation of sensitivity, specificity, positive and negative predictive values
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Parental suspicion of hearing loss (n=28) Parental perception of no hearing loss (n=248)
ears [17]. The finding was more favourable than ours, probably due to the age-related factor. In a Finnish survey of 7- to 8-year-olds, the mean conductive thresholds on both ears of the OME children ranged from 15 dB to 25 dB [23]. Comparatively, our results appeared to have rather large variations ranging from 7.5 dB to 40.6 dB. In studying mixed cases of either chronic OME or recurrent acute otitis media in the United States, Rosenfeld et al. [15] reported that the median PTA for the better-hearing ears in the children with a median age of 3.4 years was 20 dB. We did not attempt to compare the finding with our result (median PTA 15 dB), which solely represented chronic OME. Indeed, we found difficulty in making direct comparisons among published results because there were great variations in the study designs, hearing test methods, criteria in calculating the mean or median audiometric thresholds and criteria to define hearing loss. For example, Fria et al. [11] worked out the audiometric results based on the data from the randomly selected ears in the bilateral OME children, while other studies used better- or worsehearing ears or the mean of both ears. The hearing test techniques were also varied to suit the functional age of the children. Nevertheless, our findings are in line with previous paediatric study results indicating that OME may be complicated by mild to moderate hearing loss. In our study, only 10% of the parents suspected a hearing deficit in their child. The finding was, however,
Children with average PTA Thresholds >25 dB (n=17)
Children with average PTA Thresholds ≤25 dB (n=259)
2 15 Sensitivity 11.8%
26 233 Specificity 90.0%
PPV 7.1% NPV 94.0%
higher than the 2% to 7% reported for a cohort of infants in the Netherlands [9]. In a London study, Watkin et al. [24] pointed out that the percentage of parental suspicion varied with the age of the children. Older children had better communication capability, but our 6- to 7-year-old subjects were still not mature enough to express their own feelings. Our clinically relevant PPV of parental suspicion demonstrated that 82% of the positive reports were correctly associated with OME and this was higher than that reported in the Netherlands (PPV=70%) [9]. Our high specificity rate (97%) indicated that only a small percentage of the reports were false-positives. Therefore, great caution must be exercised when a parent reports a suspicion of hearing loss because the probability of expecting an OME diagnosis will be high in such a case. Although our results demonstrated a highly significant association between parental suspicion and OME, parent-suspected hearing loss was not effective for detecting the occurrence of OME. Parents who achieved a higher educational level did not show a better ability in the suspicion of hearing loss. The low sensitivity rate indeed implied a high false-negative rate (80%). In other words, if we had relied on parental suspicion as the first screening, at least 80% of the OME cases would have been missed. The parental observations also had a very poor sensitivity (12%) for predicting audiometric results. The extremely low PPV indicated that only 7% of the positive parental suspicions were correctly
Table 5 Textual statements from parents “There was earwax. My child received ear syringing previously.” “It was probably due to the fact that the accumulated earwax had not been removed for a long time.” “I once noticed that my child spoke very loudly and his hearing was poor. A large amount of earwax were found in his ears. After the earwax removal, there seems to be no problem. But he still speaks loudly.” “I wonder whether there is a hearing problem with my child’s left ear.” “I suspect that my child developed an ear problem due to the flu attack. And there was a hearing problem in the past 6 months.” “It seems that my child has had a hearing problem for about a year. She sometimes complains of a ringing noise.” “It seems that my child can’t hear properly what people are talking about. He always moves close to the television or turns the volume loud.” “It happens very often that he is not listening when I call him.” “I have to repeat the sentences. He doesn’t hear well.” “There was no response when I was talking to him.” “My child was suffering from middle ear infection when she was three years old. She had the hearing test done at that time. Her hearing has not been good recently.” “I am not sure whether or not there is a hearing problem with my child.”
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associated with PTA parameters. This finding agreed with previous study results that the parental perception of hearing loss correlated very poorly with hearing test results [2, 19]. Based on the written statements from the parents, we recognised that there were three parents who understood the relationship between hearing loss and impacted earwax. Parental awareness is enhanced by personal experience and knowledge. Unfortunately, two of these three children were found to have OME after earwax removal. Under such circumstances, the earwax could hinder parents’ ability to identify the problem caused by OME. From the other statements, we noticed that a few parents had ignored the trouble for a long time. The reason for the lack of immediate action from the parents to clarify the problem could be due to the uncertainty or instability in the observations. Or, the problem was too mild to provoke parental concern to seek professional advice. In our culture, OME generally receives poor public awareness. Apparently, the fluctuating mild hearing loss left the parents feeling puzzled about confirming a problem. The existing literature indicated that we were not the first to find parents procrastinating a professional consultation. In a UK study of 280 OME children, Maw and Tiwari [13] reported that there was a 2-year delay between the first suspicion of hearing loss and presentation to an otolaryngologist. It was unfortunate that no further studies were conducted to follow the problem. There were some weaknesses in the current study. For example, OME might have occurred in the past month but not at the time of the investigation, or vice versa. As the related hearing loss was transient and fluctuating, a record of the parental perception preceding the school screening might not have reflected the child’s situation at the time that the hearing test was performed. A dichotomous response to the survey question had its strength in facilitating the calculation of sensitivity and specificity, but it might have forced the parents to give a definite answer on the “yes” or “no” choice when they were uncertain about how to respond. For those parents who did not choose to express their decision with comments, we were not sure whether or not they simply had less concern about the problem. Behavioural or related hearing loss questions should also be added to the survey questionnaire in future studies. This study has provided some evidence in understanding the parental perception of hearing loss in children with OME in a Chinese community. As demonstrated by the PTA results, the hearing function of the majority of children with OME ranged from normal to mild loss. In conclusion, parental suspicion of hearing loss is inadequate for the identification of mild hearing loss as caused by OME. However, parental suspicion that a child is not hearing properly should lead to a careful evaluation. Our findings
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showed that parents who suspected a diminishing hearing in their child were not aware of the need to seek professional advice. Health education is recommended to improve parental awareness of the disease. Since, culturally, many parents are inert to attend health seminars, health education programmes through mass media is, perhaps, the most effective way of improving parental knowledge. Acknowledgement This study was supported by a grant from the Health Service Research Committee #531021, Hong Kong.
References 1. American Academy of Family Physicians, American Academy of Otolaryngology—Head and Neck Surgery, American Academy of Pediatrics Subcommittee on Otitis Media With Effusion (2004) Otitis media with effusion. Pediatrics 113(5):1412–1429 2. Anteunis LJ, Engel JA, Hendriks JJ, Manni JJ (1999) A longitudinal study of the validity of parental reporting in the detection of otitis media and related hearing impairment in infancy. Audiology 38(2):75–82 3. Bennett KE, Haggard MP, Silva PA, Stewart IA (2001) Behaviour and developmental effects of otitis media with effusion into the teens. Arch Dis Child 85(2):91–95 4. Brody R, Rosenfeld RM, Goldsmith AJ, Madell JR (1999) Parents cannot detect mild hearing loss in children. First place—Resident Clinical Science Award 1998. Otolaryngol Head Neck Surg 121 (6):681–686 5. Butler CC, van der Linden MK, MacMillan H, van der Wouden JC (2003) Screening children in the first four years of life to undergo early treatment for otitis media with effusion. Cochrane Database Syst Rev 2:004163 6. Cantekin EI (1983) Algorithm for diagnosis of otitis media with effusion. Ann Otol Rhinol Laryngol Suppl 92(Suppl 107):6 7. Downs MP (1980) Identification of children at risk for middle ear effusion problems. Ann Otol Rhinol Laryngol Suppl 89(3 pt 2): 168–171 8. Eliachar I (1978) Audiologic manifestations in otitis media. Otolaryngol Clin North Am 11(3):769–776 9. Engel J, Anteunis L, Volovics A, Hendriks J, Marres E (2000) Predictive value of parent-reported symptoms in the assessment of otitis media with effusion during infancy. Scand J Prim Health Care 18(1):25–29 10. Fiellau-Nikolajsen M, Lous J (1979) Prospective tympanometry in 3-year-old children. A study of the spontaneous course of tympanometry types in a nonselected population. Arch Otolaryngol 105(8):461–466 11. Fria TJ, Cantekin EI, Eichler JA (1985) Hearing acuity of children with otitis media with effusion. Arch Otolaryngol 111(1):10–16 12. Kontiokari T, Niemela M, Uhari M (1998) Middle ear effusion among children diagnosed and treated actively for acute otitis media. Eur J Pediatr 157(9):731–734 13. Maw AR, Tiwari RS (1988) Children with glue ear: How do they present? Clin Otolaryngol Allied Sci 13(3):171–177 14. Northern JL, Downs MP (2002) Hearing in children, 5th edn. Lippincott Williams & Wilkins, Philadelphia 15. Rosenfeld RM, Goldsmith AJ, Madell JR (1998) How accurate is parent rating of hearing for children with otitis media? Arch Otolaryngol Head Neck Surg 124(9):989–992 16. Sabo DL, Paradise JL, Kurs-Lasky M, Smith CG (2003) Hearing levels in infants and young children in relation to testing
Eur J Pediatr (2006) 165:851–857
17.
18.
19.
20.
technique, age group, and the presence or absence of middle-ear effusion. Ear Hear 24(1):38–47 Schilder AG, Zielhuis GA, Van Den Broek P (1993) The otological profile of a cohort of Dutch 7.5–8-year-olds. Clin Otolaryngol Allied Sci 18(1):48–54 Silva PA, Kirkland C, Simpson A, Stewart IA, Williams SM (1982) Some developmental and behavioral problems associated with bilateral otitis media with effusion. J Learn Disabil 15 (7):417–421 Stewart MG, Ohlms LA, Friedman EM, Sulek M, Duncan NO 3rd, Fernandez AD, Bautista MH (1999) Is parental perception an accurate predictor of childhood hearing loss? A prospective study. Otolaryngol Head Neck Surg 120(3):340–344 Tong MC, Yue V, Ku PK, Lo PS, van Hasselt CA (2000) Screening for otitis media with effusion to measure its prevalence in Chinese children in Hong Kong. Ear Nose Throat J 79(8): 626–630
857 21. Tong MC, Yue V, Ku PK, Lo PS, Wong EM, van Hasselt CA (2006) Risk factors for otitis media with effusion in Chinese schoolchildren: a nested case–control study and review of the literature. Int J Pediatr Otorhinolaryngol 70(2):213–219 22. van Cauwenberge P, Watelet JB, Dhooge I (1999) Uncommon and unusual complications of otitis media with effusion. Int J Pediatr Otorhinolaryngol Suppl 49(Suppl 1):S119–S1125 23. Virolainen E, Puhakka H, Aantaa E, Tuohimaa P, Ruuskanen O, Meurman OH (1980) Prevalence of secretory otitis media in seven to eight year old school children. Ann Otol Rhinol Laryngol Suppl 89(3 Pt 2):7–10 24. Watkin PM, Baldwin M, Laoide S (1990) Parental suspicion and identification of hearing impairment. Arch Dis Child 65(8):846–850 25. Zielhuis GA, Gerritsen AA, Gorissen WH, Dekker LJ, Rovers MM, van der Wilt GJ, Ingels K (1998) Hearing deficits at school age; the predictive value of otitis media in infants. Int J Pediatr Otorhinolaryngol 44(3):227–234
