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early acquired hearing disability. Who takes the initiative?
International Journal of Pediatric Otorhinolaryngology, 7 (1984) 107-117
107
Elsevier POR 00235
Early detection and identification of congenital/early acquired hearing disability. Who takes the initiative? A.
Parving
A udiology Department, Gentofte University Hospital, DK - 2900 Hellerup (Denmark)
(Received June 10th, 1983) (Revised July 7th, 1983) (Accepted January 18th, 1984) Key words: congenital hearing loss - early detection - identification of hearing thresholds - initiators of
hearing threshold assessment
Summaw Questionnaires were distributed to parents of hearing-impaired children (average of the hearing thresholds >/35 dB at 500, 1000 and 2000 Hz) in order to perform an evaluation concerning the initiators of the detection and identification of congenital/early acquired hearing impairment. In 59% (23/39) the parents were the first to suspect the hearing loss. In 13% (5/39) the child failed the auditory screening test. In 16% (6/39) the child was regisiered as at risk and in 13% (5/39) the suspicion was raised by trained personnel in nurseries. In 43% (17/39) more than 4 weeks passed from the time the first suspicion was raised until a valid hearing threshold determination was performed. This delay was caused by health personnel in 59% (10/17). The median age at the hearing threshold assessment was 20 months (range 4 - 4 8 months) in this group of children. Only 3370 (13/39) were diagnosed at the age of 1 year, despite the fact that the hearing loss was either congenital or acquired during the neonatal period. It is concluded that the parents are the first initiators of the identification of their hearing-impaired child, but the point of time at which the hearing loss is identified is still unacceptably late in most cases. Proposals for an improved early detection and identification of hearing-impaired children are made in order to prevent developmental disorders in speech, language, psychological and mental behavior.
Correspondence: A. Parving, Audiology Department, Gentofte University Hospital, DK-2900 Hellerup,
Denmark. 0165-5876/84/$03.00 © 1984 Elsevier Science Publishers B.V.
108 Introduction
Early detection, identification and treatment of congenital/early acquired (within the first 9-12 months of life) hearing disability is of essential importance for the behavioral, mental and language development of a child. The challenge of an early detection of hearing impairment has resulted in a variety of methods for screening the hearing ability of neonates or infants, ranging from observation of the infant's reaction to one or a few well-defined sound stimuli [3-6,12,17,28] to different methods of objective registration of the hearing thresholds [10,11,26,27]. However, several investigations evaluating the sensitivity of different hearing screening procedures have demonstrated a rate of 1-3% false-positives (i.e. fail the screening test despite normal hearing) or, worse, a high rate of 22-76% false-negatives (i.e. pass the test despite hearing loss ) [19]. This methodological insufficiency based on presently available hearing screening procedures indicate that mass hearing screening is of limited value and cannot be justified in terms of cost effectiveness. Hearing screening based on high-risk registration was introduced by Mencher [18] and has been applied as an approach to early detection of hearing impairment. However, among all children with congenital/early acquired hearing impairment (in this context during the neonatal period), only about 50% belong to the at-risk group [7,22,25]. Moreover, data on hearing screening by high-risk registration demonstrate a varying degree of registration activity despite fixed registration criteria [5,8,13]. The efficiency of this hearing screening procedure has therefore been questioned [14,19]. Based on the investigations demonstrating the invalidity and inefficiency of different hearing screening procedures, a retrospective examination was performed in an attempt to contribute to the evaluation concerning the initiators of the detection and identification of congenital/early acquired hearing impairment.
Procedures
From a previously published series of 149 children (median age 23 months, range 2-123 months) subjected to electrocochleography (ECoG) for various reasons during the period 1969-1979 [20,21], 67 (31 boys and 36 girls) were diagnosed as suffering from hearing disability. These 67 hearing disabled children constitute the basis for the present investigation. The criterion for hearing disability (i.e. the selection criterion) was an average of the hearing thresholds of >~ 35 dB HL at 500, 1000 and 20000 Hz (i.e. threshold Carhart (TC)) for the better hearing ear. The parents of the hearing-disabled children received a questionnaire comprising the following questions: Who first suspected the hearing loss? What raised the suspicion? Who referred the child to audiological evaluation? Was threshold identification delayed and, if so, who caused the delay? (Table I). The exact time of the first reliable assessment of the hearing sensitivity was taken from the hospital records. In 64 children this time corresponded to the date of the ECoG investigation, which was actually performed to identify the hearing thresholds, whereas in 3 children the ECoG investigation was performed to classify the type of
109
hearing loss. In these 3 cases the time of performance of the first pure-tone audiogram (PTA) was recorded. In addition, for all the children the following were noted: The time of onset of the hearing disorder; the degree of hearing loss (TC) in the better hearing ear, and the degree of hearing loss related to the age at which the thresholds were identified. Furthermore, based on an extensive clinical evaluation, the etiology of the hearing disorder was indicated [20]. On the basis of this information and on the replies to the questionnaire, the children were subdivided into 3 groups: A, B and C, which will be described separately.
Material
Group A This comprises 39 children (23 girls, 16 boys) whose parents responded to the questions given in Table I. The year of birth of the children is shown in Fig. 1. In this group, 38 children had congenital/early acquired hearing impairment and one child acquired the hearing loss after the age of 9 months due to Meniere's disorder (retrospective information on fluctuating hearing loss, 'dizziness', and reduced caloric reaction at follow-up examinations). In this patient the hearing thresholds were first obtained by PTA. The different etiologies of the hearing disorder are
TABLE I THE QUESTIONNAIRE DISTRIBUTED TO 51 PARENTS OF HEARING IMPAIRED CHILDREN The criterion for hearing impairment is the average of 500, 1000 and 2000 Hz >/35 dB HL for the better hearing ear. I. Who first suspected that your child has a hearing loss? (a) You? (b) Close relative? (c) Health visitor? (d) General practitioner? (e) ENT-physician? (f) Other person, who? II. What raised the suspicion of hearing loss? (a) No reaction to sound (e.g. speech, noisy toys, radio, TV, etc.)? (b) Examination of your child's reaction to sound sources used by health visitors, doctors, nurseries, etc.? (c) Lacking speech perception? (d) Lacking speech development? (e) Slow or retarded development? Ill.Who referred your child to audiological examination? IV. Did the audiological examination take place later than 4 weeks after the suspicion of hearing loss had been raised? If yes, please give the reason for the delay. V. How old was your child when treatment was begun?
110
A
19'80"yemr o! birth
19~o
19'7s
~,~ 1980 year
Of birth
C
t
1980 year Of birth
Fig. 1. Year of birth in each of the 3 groups A, B and C.
indicated in Table II. The median age at the first hearing threshold determination obtained by ECoG was 20 months, range 4-48 months.
Group B This comprises 12 children (5 girls, 7 boys) whose parents did not respond to the questionnaire. In 9 cases no responses were given at all (3 were foreigners and probably unfamiliar with the Danish language) and in 3 cases the parents did not wish to participate in the investigation. One parent explained that the child had
111
normal hearing ability, which might suggest that the ECoG investigation had estimated a false-positive hearing loss [20]. The year of birth of the children is shown in Fig. 1 and the different etiologies of the hearing impairment are indicated in Table II. In 8 children the hearing loss was considered to be congenital or acquired before the age of 9 months; in 3 cases the hearing loss was acquired after the age of one year, and one child had normal hearing, as mentioned above. The median age at the first hearing threshold identification obtained by ECoG in all patients was 28 months, range 4 - > 60 months.
Group C This comprises 16 children (8 girls and 8 boys). No questionnaires were sent to the parents in this group, as they could not be located due to changes of address in 10 cases. In this context it should be mentioned that children from all Denmark are referred to the Gentofte University Hospital as this audiological department so far is the only one where ECoG is performed. In 6 cases no questionnaire was sent predominantly for ethical reasons as the children had other severe handicaps in addition to their hearing disability. The year of birth of the children is shown in Fig. 1 and the different etiologies of the hearing disorder are indicated in Table II. The median age at the first identification of the hearing thresholds by ECoG in all but two patients was 32 months, range 5-122 months. In 13 children the hearing loss was considered to be congenital; in one child the hearing loss was acquired after the age of 9 months, and in two children no firm conclusion as to the onset of the hearing loss could be made. Besides the lack of responses to the questionnaire in groups B and C, these groups differed slightly from group A with respect to age TABLE II THE ETIOLOGY OF THE HEARING DISORDER IN THE DIFFERENT GROUPS (A,B,C) COMPRISING 67 CHILDREN SELECTED FROM 149 CHILDREN IN WHOM ECoG HAD BEEN PERFORMED Group A (n = 39) Natal/neonatal complications Foetal rubella infection Ototoxic drugs (gentamycin) Inheritance Unknown cause Goldenhar's syndrome Waardenburg's syndrome Malformation of outer ears Meniere's disorder Chromosomal anomaly Meningitis Head injury (Normal hearing) Total
4 12 1 8 8 1 1 2 1 1
Group B (n =12)
Group C (n =16)
2 4 1
1
1 39
I-~
l--d
112 distribution, time of onset and etiology of hearing loss. Owing to lack of information groups B and C cannot contribute to the further evaluation of the problems concerning an early detection and identification of hearing disability and therefore these groups will not be further evaluated.
Results The responses to the questions outlined in Table I gave the following results: In 59% (23/39) of the children the parents were the first to suspect the hearing loss, either because of a known disposition for hearing loss in the family (n = 1); obvious malformations of the ears (n = 2); or because the child did not react properly to sounds (n = 20). In 13% (5/39) the child failed the auditory screening test (BOEL test performed by the health visitor), and in 16% (6/39) the child was registered as at risk and referred for audiological evaluation. In 13% (5/39) the suspicion was raised by trained personnel in nurseries because of poor speech development a n d / o r signs of general retardation. In 74% (29/39) the general practitioners referred the child; in 16% (6/39) referral was made by the health visitors, and in 10% (4/39) the parents requested the audiological examination. In 43% (17/39) more than 4 weeks passed from the time the suspicion was raised until a valid hearing threshold determination was perN 20
15
10
35-45
46-55
56-65
66-75
76-85
86-95
:'9
TC
Fig. 2. Distribution of the degreeof hearing loss in group A (open columns). For comparison, the degree of hearing loss in group B (hatched columns) is indicated.
113
formed. In 59% (10/17) this delay was caused by health personnel (i.e. health visitors, general practitioners, ENT-physicians) and in 11% (2/17) the reason for the delay was a severely affected general condition of the child. In 20% (3/17) the delay was due to unavoidable 'errors in the system' (holidays, change of address, lack of records, etc.), and in 117o (2/17) no reply was given to this question. In all but one (with Meniere's disorder) of these 39 children the hearing loss was considered to the congenital/early acquired (Table II). As mentioned previously, the median age at the hearing threshold assessment was 20 months (range 4-48 months), and in Fig. 3 is indicated the relationship between the degree of hearing loss (TC) and the age in months at which the hearing impairment was confirmed by ECoG and thus a valid threshold identification was obtained in each individual child. The figure shows that in 7470 (29/39) of the children the hearing thresholds were assessed at the age of 2 years, whereas only 3370 (13/39) were diagnosed at the age of 1 year despite the fact that the hearing loss was either congenital or acquired during the neonatal period (Table II). With regard to the question concerning the onset of hearing aid treatment, the majority of parents indicated only approximate dates. The median age was estimated to 19 months (range 4-48 months), indicating that there is no major delay in the institution of hearing aid treatment once the hearing thresholds have been identified (two children were not treated with hearing aids because of a combined peripheral/central hearing disorder).
TC
> 95
**
=
*~***
=*
**
**
86-95-
76-85-
66-75-
56- 6.5 -
46-55-
35-45-
I
I
5
10
*
I
I
I
I
I
I
15
20
25
30
38
40
/
'
48
months
Fig. 3. The relationship in each child between the degree of hearing loss (TC) and the age in months at which the hearing threshold identification was made by ECoG.
114 Discussion
The results of the present investigation demonstrate that in more than half of the hearing-impaired children (TC >1 35 dB HL) the parents were the first to suspect the reduced hearing ability of their child. This 'screening' by the parents exhibits a methodological sensitivity that equals that of many systematic hearing screening procedures [1,2,5]. Although one of the important effects of the systematic hearing screening procedures may be an increased awareness of the auditory function, it may on the other hand give rise to a dangerous false security of intact hearing based on a false pass of the screening test (i.e. a false-negative outcome). A Swedish examination of preschool children demonstrated that in 31% of cases the parents were the main initiators of the hearing assessment in children with impaired hearing. In 28%, the child welfare clinics were the initiators [14]. In many of the cases referred by the welfare clinics, however, the parents may have made the first initiative, as also suggested by Kankkunen herself when she writes: 'It should be noted, however, that the parents usually contacted the child welfare clinic first and the child was referred from there to the audiology department' [14]. Only 17% were high-risk registered children referred for audiological evaluation, which corresponds to the 16% (6/39) found in the present investigation. This also means that high-risk registration is highly inefficient. The results on the referral of the children (74% by the general practitioners) may be regarded as reflecting the organization of the Danish health system, in which the parents are usually advised to visit their own general practitioner, who then makes the referral (on the parents' request?). The fact that the delay in threshold identification is caused by health personnel in 59% (10/17) seems to indicate that the organization of the health system may be a draw-back for an early identification. In only 10% (4/39) the parents contacted the audiological department directly. In this context it should perhaps be considered that the parents may be easily convinced that their child is completely normal. All parents suspecting a severe handicap in their child will be psychologically ready to accept a statement of normality from professional authorities, thus giving the parents a false security of having a normally heating child. In addition, the replies to the questionnaire indicated that there is a profound sense of bitterness--even years later-- towards the professional health personnel, who neither seriously believed nor accepted, or examined the validity of the parents' suspicion. The bitterness often resulted in aggression or resistance towards the health system which may seriously affect the possibility of future evaluation and follow-up examinations. Medical advice to consult an audiological department is not obligatory and to avoid any delays, parents should be informed more directly that the audiological departments and clinics are open for direct admission. In a previous epidemiological investigation including 117 children born during the 10-year-period from 1970 to 1980 only 63% of the children with predominantly congenital hearing loss were identified at the age of 3 years [22]. It compares extremely well with the 60% identified at the same age in Kankkunen's investigation [14] and fairly well with the 50% identified at age 3 in the European communities
115 (the hearing loss was defined as >150 dB HL for the average of 500, 1000 and 2000 Hz for the better hearing ear) [16]. In contrast, only 15.7% were identified at this age in the investigation published by Ruben and Rozycki [23]. The prevalence rate of congenital/early acquired hearing loss is relatively similar within the western civilization and thus the significant differences may be explained by discrepances in the organization of the health systems and/or to variations in the time periods during which the investigations were performed. However, the differences in the time of threshold identification may also reflect major differences in political, social and cultural backgrounds. In the present investigation 74% of the children were identified at the age of 2 years, which is a significantly higher rate compared with that in the Swedish (56%) and European (30%) investigations and also with the Danish investigation previously mentioned [22]. This can probably be ascribed to the selection of the present material; the limited number of subjects, and the distribution of the degree of hearing impairment in group A (Figs. 2 and 3). Thus, unfortunately, this high rate of identified children at the age of 2 years cannot be considered reliable. The invalidity is further supported by the increased median age at threshold identification in groups B and C. The relationship between the age at hearing threshold identification and the degree of hearing loss (Fig. 3) indicates that hearing losses > 95 dB HL may be unidentified after the age of 1 year. This delayed identification may have serious consequences for the child who is deprived of mandatory training and treatment. However, recommendation of early identification of moderate-to-severe hearing losses (i.,e. 40-80 dB HL as the average of 500, 1000 and 2000 Hz for the better hearing ear) is also required in order to avoid impaired speech and language development [24]. Preliminary results of speech and language characteristics of children with mild hearing losses (i.e. 15-39 dB HL as the average of 500, 1000 and 2000 Hz for the better hearing ear) indicate that on an average the hearing thresholds are identified at age 9.7 years and that also these children have speech and language deficits [9]. The rate of only 50-63% identified at the age of 3 years [14,16,22] indicates that early detection and identification of congenital/early acquired hearing impairment is a serious and as yet unsolved problem and that auditory hearing screening, whatever the method, has largely failed its aim. However, the program concerning early detection and identification set up in G6teborg during the period 1970-1980 has proved that early diagnosis may be improved by intensive information to all parents with new-born babies describing the importance of the hearing organ and informing the parents on where to go if they are worried about their child's hearing ability [14]. The regular child examinations at the general practitioners' during preschool age may improve the rate of identification of hearing impairment [15]. However, these examinations do not seem to contribute to the detection of congenital hearing loss, but they may contribute to early diagnosis of late onset hearing impairment [14].
116
Conclusion T h e p a r e n t s are the first initiators of the i d e n t i f i c a t i o n of their h e a r i n g - i m p a i r e d child, b u t the time o f identification of c o n g e n i t a l / e a r l y acquired h e a r i n g loss is still u n a c c e p t a b l y late in m o s t cases. T o i m p r o v e the early detection, i n f o r m a t i o n on the i m p o r t a n c e of the hearing o r g a n should be given to all p a r e n t s at their child's delivery a n d at regular health c o n t r o l e x a m i n a t i o n s . T h e general p r a c t i t i o n e r s should m a k e careful records t h r o u g h o u t infancy of s o u n d reactions c o m b i n e d with i n f o r m a l testing. T h e c o m b i n a t i o n of i n f o r m a t i o n to the p a r e n t s a n d t h o r o u g h testing at the h e a l t h control e x a m i n a t i o n s m a y facilitate early identification of the h e a r i n g - i m p a i r e d child. F u r t h e r m o r e , e m p h a s i s should be laid on the i m p o r t a n c e of the hearing o r g a n when e d u c a t i n g p e r s o n n e l dealing with infants a n d children, i.e. health visitors, teachers, nurses, medical students, general practitioners, p e d i a t r i c i a n s , etc. T h e s e suggestions together with the m a i n t e n a n c e of o p e n clinics (i.e. no o b l i g a t o r y m e d i c a l referral), m a y result in an earlier identification a n d t r e a t m e n t of hearing loss. In this way d e v e l o p m e n t a l disorders in speech, language, psychological a n d m e n t a l b e h a v i o r m a y be prevented.
Acknowledgement This s t u d y was s u p p o r t e d b y Rosalie Petersen's F o u n d a t i o n .
References 1 Barr, B., Early identification of hearing impairment. In I.G. Taylor and A. Markides (Eds.), Disorders of Auditory Function, Ill, Academic Press, London, 1980, pp. 33-42. 2 Bentzen, O. and Jensen, J.H., Early detection and treatment of deaf children. A European concept. In S.E. Gerber and G.T. Mencher (Eds.), Early Management of Hearing Loss, Grune and Stratton, San Fransisco, 1981, pp. 85-103. 3 Bradford, L. and Roussey, C., Respiration audiometry, Maico Audiol. Library Ser., 10 (1972) 22-24. 4 Downs, M.P. and Sterritt, G., Identification audiometry for neonates. A preliminary report, J. aud. res. 4 (1964) 69-80. 5 Downs, M.P., Auditory screening, Otolaryng. Clin. North Amer, 11 (1978) 611-629. 6 Downs, M.P., Return to the basics of screening. In S.E. Gerber and G.T. Mencher (Eds.), Early Diagnosis of Hearing Loss, Grune and Stratton, New York, 1978, pp. 129-154. 7 Feinmesser, M., Tell, L. and Levi, H., Follow-up of 40.000 infants screened for hearing defect, Audiology, 21 (1982) 197-203. 8 Feinmesser, M. and Tell, L., Neonatal screening for detection of deafness, Arch. Otolaryng., 102 (1976) 297-299. 9 Gershel, J. and Ruben R.J., Preliminary results of speech and language characteristics of children with 15-39 dB hearing loss in the better hearing ear, 1982, Personal communication. 10 Galambos, R. and Depsland, P.-A., The auditory brain stem response (ABR) as a useful diagnostic tool in the intensive care nursery, Pediat. Res., 14 (1980) 154-158. 11 Himmelfarb, M.Z., Popelka, G.R. and Margolis, R.H., Acoustic reflex. Evaluation in neonates. In S.E. Gerber and G.T. Mencher (Eds.), Early Diagnosis of Hearing Loss, Grune and Stratton, New York, 1978, pp. 109-127.
117 12 Hodgson, W.R., Testing infants and young children. In D.R. Katz (Ed.), Handbook of Clinical Audiology (2nd edn.), Williams and Wilkins, Baltimore, 1978, pp. 397-409. 13 Kankkunen, A. and Liden, G., How efficient is high-risk register for identifying children with impaired hearing. In Proc. XV Int. Congr. Audiology, Krakow, 1980 (abstr.). 14 Kankkunen, A., Pre-school children with impaired hearing, Acta. Otolaryng., Suppl. 391 (1982). 15 KShler, L., Health control of four-year-old children, Acta paediatr. Suppl. 235 (1973). 16 Martin, J.A.M., Diagnosis and communicative ability in deaf children in the European Community, Audiology, 21 (1982) 185-196. 18 Mencher, G.T., A program for neonatal hearing screening, Audiology, 13 (1974) 495-500. 19 Parring, A., Etiologisk udredning red horetab hos born, Nord. Med, 97 (1982) 17-19. 20 Parving, A., Elberling, C. and Salomon, G., ECoG and psycho-acoustic tests compared in identification of hearing loss in young children, Audiology, 20 (1981) 365-381. 21 Parring, A. and Elberling, C., Clinical Application of Electrocochleography in Children. In C.G. Chiarenza and D. Papakostopoulos (Eds.), Clinical Application of Cerebral Evoked Potentials in Pediatric Medicine, Exerpta Medica, Amsterdam. 22 Parving, A., Epidemiology of hearing loss and aetiological diagnosis of hearing impairment in childhood, Int. J. pediat. Otorhinolaryng., 5 (1983) 151-165. 23 Ruben, R.H. and Rozycki, D., Diagnostic screening for the deaf child, Arch. otolaryng. 91 (1970) 429-432. 24 Ruben, R.J. et al., Moderate to severe sensorineural hearing impaired child. Analysis of aetiology, intervention and outcome, Laryngoscope, 92 (1982) 38-46. 25 Sarno, C.N. and Clemis, J.D., A workable approach to the identification of neonatal hearing impairment, Laryngoscope, 90 (1980) 1313-1320. 26 Schulman-Galambos, C. and Galambos, R., Brain stem evoked response audiometry in newborn screening, Arch. Otolaryng., 105 (1979) 86-90. 27 Simmons, F.B., Automated screening test for newborns. The crib-o-gram. In J.B. Jaffe (Ed.), Hearing Loss in Children, University Park Press, Baltimore, 1977, pp. 89-98. 28 Stensland-Junker, K., Barr, B., Maliniemi, S. and Wasz-H~Sckert, O. BOEL-screening. A program for the early detection of communicative disorders. Preliminary reports from a study on 1.000 Finnish infants, Audiology, 17 (1978) 51-62.
107
Elsevier POR 00235
Early detection and identification of congenital/early acquired hearing disability. Who takes the initiative? A.
Parving
A udiology Department, Gentofte University Hospital, DK - 2900 Hellerup (Denmark)
(Received June 10th, 1983) (Revised July 7th, 1983) (Accepted January 18th, 1984) Key words: congenital hearing loss - early detection - identification of hearing thresholds - initiators of
hearing threshold assessment
Summaw Questionnaires were distributed to parents of hearing-impaired children (average of the hearing thresholds >/35 dB at 500, 1000 and 2000 Hz) in order to perform an evaluation concerning the initiators of the detection and identification of congenital/early acquired hearing impairment. In 59% (23/39) the parents were the first to suspect the hearing loss. In 13% (5/39) the child failed the auditory screening test. In 16% (6/39) the child was regisiered as at risk and in 13% (5/39) the suspicion was raised by trained personnel in nurseries. In 43% (17/39) more than 4 weeks passed from the time the first suspicion was raised until a valid hearing threshold determination was performed. This delay was caused by health personnel in 59% (10/17). The median age at the hearing threshold assessment was 20 months (range 4 - 4 8 months) in this group of children. Only 3370 (13/39) were diagnosed at the age of 1 year, despite the fact that the hearing loss was either congenital or acquired during the neonatal period. It is concluded that the parents are the first initiators of the identification of their hearing-impaired child, but the point of time at which the hearing loss is identified is still unacceptably late in most cases. Proposals for an improved early detection and identification of hearing-impaired children are made in order to prevent developmental disorders in speech, language, psychological and mental behavior.
Correspondence: A. Parving, Audiology Department, Gentofte University Hospital, DK-2900 Hellerup,
Denmark. 0165-5876/84/$03.00 © 1984 Elsevier Science Publishers B.V.
108 Introduction
Early detection, identification and treatment of congenital/early acquired (within the first 9-12 months of life) hearing disability is of essential importance for the behavioral, mental and language development of a child. The challenge of an early detection of hearing impairment has resulted in a variety of methods for screening the hearing ability of neonates or infants, ranging from observation of the infant's reaction to one or a few well-defined sound stimuli [3-6,12,17,28] to different methods of objective registration of the hearing thresholds [10,11,26,27]. However, several investigations evaluating the sensitivity of different hearing screening procedures have demonstrated a rate of 1-3% false-positives (i.e. fail the screening test despite normal hearing) or, worse, a high rate of 22-76% false-negatives (i.e. pass the test despite hearing loss ) [19]. This methodological insufficiency based on presently available hearing screening procedures indicate that mass hearing screening is of limited value and cannot be justified in terms of cost effectiveness. Hearing screening based on high-risk registration was introduced by Mencher [18] and has been applied as an approach to early detection of hearing impairment. However, among all children with congenital/early acquired hearing impairment (in this context during the neonatal period), only about 50% belong to the at-risk group [7,22,25]. Moreover, data on hearing screening by high-risk registration demonstrate a varying degree of registration activity despite fixed registration criteria [5,8,13]. The efficiency of this hearing screening procedure has therefore been questioned [14,19]. Based on the investigations demonstrating the invalidity and inefficiency of different hearing screening procedures, a retrospective examination was performed in an attempt to contribute to the evaluation concerning the initiators of the detection and identification of congenital/early acquired hearing impairment.
Procedures
From a previously published series of 149 children (median age 23 months, range 2-123 months) subjected to electrocochleography (ECoG) for various reasons during the period 1969-1979 [20,21], 67 (31 boys and 36 girls) were diagnosed as suffering from hearing disability. These 67 hearing disabled children constitute the basis for the present investigation. The criterion for hearing disability (i.e. the selection criterion) was an average of the hearing thresholds of >~ 35 dB HL at 500, 1000 and 20000 Hz (i.e. threshold Carhart (TC)) for the better hearing ear. The parents of the hearing-disabled children received a questionnaire comprising the following questions: Who first suspected the hearing loss? What raised the suspicion? Who referred the child to audiological evaluation? Was threshold identification delayed and, if so, who caused the delay? (Table I). The exact time of the first reliable assessment of the hearing sensitivity was taken from the hospital records. In 64 children this time corresponded to the date of the ECoG investigation, which was actually performed to identify the hearing thresholds, whereas in 3 children the ECoG investigation was performed to classify the type of
109
hearing loss. In these 3 cases the time of performance of the first pure-tone audiogram (PTA) was recorded. In addition, for all the children the following were noted: The time of onset of the hearing disorder; the degree of hearing loss (TC) in the better hearing ear, and the degree of hearing loss related to the age at which the thresholds were identified. Furthermore, based on an extensive clinical evaluation, the etiology of the hearing disorder was indicated [20]. On the basis of this information and on the replies to the questionnaire, the children were subdivided into 3 groups: A, B and C, which will be described separately.
Material
Group A This comprises 39 children (23 girls, 16 boys) whose parents responded to the questions given in Table I. The year of birth of the children is shown in Fig. 1. In this group, 38 children had congenital/early acquired hearing impairment and one child acquired the hearing loss after the age of 9 months due to Meniere's disorder (retrospective information on fluctuating hearing loss, 'dizziness', and reduced caloric reaction at follow-up examinations). In this patient the hearing thresholds were first obtained by PTA. The different etiologies of the hearing disorder are
TABLE I THE QUESTIONNAIRE DISTRIBUTED TO 51 PARENTS OF HEARING IMPAIRED CHILDREN The criterion for hearing impairment is the average of 500, 1000 and 2000 Hz >/35 dB HL for the better hearing ear. I. Who first suspected that your child has a hearing loss? (a) You? (b) Close relative? (c) Health visitor? (d) General practitioner? (e) ENT-physician? (f) Other person, who? II. What raised the suspicion of hearing loss? (a) No reaction to sound (e.g. speech, noisy toys, radio, TV, etc.)? (b) Examination of your child's reaction to sound sources used by health visitors, doctors, nurseries, etc.? (c) Lacking speech perception? (d) Lacking speech development? (e) Slow or retarded development? Ill.Who referred your child to audiological examination? IV. Did the audiological examination take place later than 4 weeks after the suspicion of hearing loss had been raised? If yes, please give the reason for the delay. V. How old was your child when treatment was begun?
110
A
19'80"yemr o! birth
19~o
19'7s
~,~ 1980 year
Of birth
C
t
1980 year Of birth
Fig. 1. Year of birth in each of the 3 groups A, B and C.
indicated in Table II. The median age at the first hearing threshold determination obtained by ECoG was 20 months, range 4-48 months.
Group B This comprises 12 children (5 girls, 7 boys) whose parents did not respond to the questionnaire. In 9 cases no responses were given at all (3 were foreigners and probably unfamiliar with the Danish language) and in 3 cases the parents did not wish to participate in the investigation. One parent explained that the child had
111
normal hearing ability, which might suggest that the ECoG investigation had estimated a false-positive hearing loss [20]. The year of birth of the children is shown in Fig. 1 and the different etiologies of the hearing impairment are indicated in Table II. In 8 children the hearing loss was considered to be congenital or acquired before the age of 9 months; in 3 cases the hearing loss was acquired after the age of one year, and one child had normal hearing, as mentioned above. The median age at the first hearing threshold identification obtained by ECoG in all patients was 28 months, range 4 - > 60 months.
Group C This comprises 16 children (8 girls and 8 boys). No questionnaires were sent to the parents in this group, as they could not be located due to changes of address in 10 cases. In this context it should be mentioned that children from all Denmark are referred to the Gentofte University Hospital as this audiological department so far is the only one where ECoG is performed. In 6 cases no questionnaire was sent predominantly for ethical reasons as the children had other severe handicaps in addition to their hearing disability. The year of birth of the children is shown in Fig. 1 and the different etiologies of the hearing disorder are indicated in Table II. The median age at the first identification of the hearing thresholds by ECoG in all but two patients was 32 months, range 5-122 months. In 13 children the hearing loss was considered to be congenital; in one child the hearing loss was acquired after the age of 9 months, and in two children no firm conclusion as to the onset of the hearing loss could be made. Besides the lack of responses to the questionnaire in groups B and C, these groups differed slightly from group A with respect to age TABLE II THE ETIOLOGY OF THE HEARING DISORDER IN THE DIFFERENT GROUPS (A,B,C) COMPRISING 67 CHILDREN SELECTED FROM 149 CHILDREN IN WHOM ECoG HAD BEEN PERFORMED Group A (n = 39) Natal/neonatal complications Foetal rubella infection Ototoxic drugs (gentamycin) Inheritance Unknown cause Goldenhar's syndrome Waardenburg's syndrome Malformation of outer ears Meniere's disorder Chromosomal anomaly Meningitis Head injury (Normal hearing) Total
4 12 1 8 8 1 1 2 1 1
Group B (n =12)
Group C (n =16)
2 4 1
1
1 39
I-~
l--d
112 distribution, time of onset and etiology of hearing loss. Owing to lack of information groups B and C cannot contribute to the further evaluation of the problems concerning an early detection and identification of hearing disability and therefore these groups will not be further evaluated.
Results The responses to the questions outlined in Table I gave the following results: In 59% (23/39) of the children the parents were the first to suspect the hearing loss, either because of a known disposition for hearing loss in the family (n = 1); obvious malformations of the ears (n = 2); or because the child did not react properly to sounds (n = 20). In 13% (5/39) the child failed the auditory screening test (BOEL test performed by the health visitor), and in 16% (6/39) the child was registered as at risk and referred for audiological evaluation. In 13% (5/39) the suspicion was raised by trained personnel in nurseries because of poor speech development a n d / o r signs of general retardation. In 74% (29/39) the general practitioners referred the child; in 16% (6/39) referral was made by the health visitors, and in 10% (4/39) the parents requested the audiological examination. In 43% (17/39) more than 4 weeks passed from the time the suspicion was raised until a valid hearing threshold determination was perN 20
15
10
35-45
46-55
56-65
66-75
76-85
86-95
:'9
TC
Fig. 2. Distribution of the degreeof hearing loss in group A (open columns). For comparison, the degree of hearing loss in group B (hatched columns) is indicated.
113
formed. In 59% (10/17) this delay was caused by health personnel (i.e. health visitors, general practitioners, ENT-physicians) and in 11% (2/17) the reason for the delay was a severely affected general condition of the child. In 20% (3/17) the delay was due to unavoidable 'errors in the system' (holidays, change of address, lack of records, etc.), and in 117o (2/17) no reply was given to this question. In all but one (with Meniere's disorder) of these 39 children the hearing loss was considered to the congenital/early acquired (Table II). As mentioned previously, the median age at the hearing threshold assessment was 20 months (range 4-48 months), and in Fig. 3 is indicated the relationship between the degree of hearing loss (TC) and the age in months at which the hearing impairment was confirmed by ECoG and thus a valid threshold identification was obtained in each individual child. The figure shows that in 7470 (29/39) of the children the hearing thresholds were assessed at the age of 2 years, whereas only 3370 (13/39) were diagnosed at the age of 1 year despite the fact that the hearing loss was either congenital or acquired during the neonatal period (Table II). With regard to the question concerning the onset of hearing aid treatment, the majority of parents indicated only approximate dates. The median age was estimated to 19 months (range 4-48 months), indicating that there is no major delay in the institution of hearing aid treatment once the hearing thresholds have been identified (two children were not treated with hearing aids because of a combined peripheral/central hearing disorder).
TC
> 95
**
=
*~***
=*
**
**
86-95-
76-85-
66-75-
56- 6.5 -
46-55-
35-45-
I
I
5
10
*
I
I
I
I
I
I
15
20
25
30
38
40
/
'
48
months
Fig. 3. The relationship in each child between the degree of hearing loss (TC) and the age in months at which the hearing threshold identification was made by ECoG.
114 Discussion
The results of the present investigation demonstrate that in more than half of the hearing-impaired children (TC >1 35 dB HL) the parents were the first to suspect the reduced hearing ability of their child. This 'screening' by the parents exhibits a methodological sensitivity that equals that of many systematic hearing screening procedures [1,2,5]. Although one of the important effects of the systematic hearing screening procedures may be an increased awareness of the auditory function, it may on the other hand give rise to a dangerous false security of intact hearing based on a false pass of the screening test (i.e. a false-negative outcome). A Swedish examination of preschool children demonstrated that in 31% of cases the parents were the main initiators of the hearing assessment in children with impaired hearing. In 28%, the child welfare clinics were the initiators [14]. In many of the cases referred by the welfare clinics, however, the parents may have made the first initiative, as also suggested by Kankkunen herself when she writes: 'It should be noted, however, that the parents usually contacted the child welfare clinic first and the child was referred from there to the audiology department' [14]. Only 17% were high-risk registered children referred for audiological evaluation, which corresponds to the 16% (6/39) found in the present investigation. This also means that high-risk registration is highly inefficient. The results on the referral of the children (74% by the general practitioners) may be regarded as reflecting the organization of the Danish health system, in which the parents are usually advised to visit their own general practitioner, who then makes the referral (on the parents' request?). The fact that the delay in threshold identification is caused by health personnel in 59% (10/17) seems to indicate that the organization of the health system may be a draw-back for an early identification. In only 10% (4/39) the parents contacted the audiological department directly. In this context it should perhaps be considered that the parents may be easily convinced that their child is completely normal. All parents suspecting a severe handicap in their child will be psychologically ready to accept a statement of normality from professional authorities, thus giving the parents a false security of having a normally heating child. In addition, the replies to the questionnaire indicated that there is a profound sense of bitterness--even years later-- towards the professional health personnel, who neither seriously believed nor accepted, or examined the validity of the parents' suspicion. The bitterness often resulted in aggression or resistance towards the health system which may seriously affect the possibility of future evaluation and follow-up examinations. Medical advice to consult an audiological department is not obligatory and to avoid any delays, parents should be informed more directly that the audiological departments and clinics are open for direct admission. In a previous epidemiological investigation including 117 children born during the 10-year-period from 1970 to 1980 only 63% of the children with predominantly congenital hearing loss were identified at the age of 3 years [22]. It compares extremely well with the 60% identified at the same age in Kankkunen's investigation [14] and fairly well with the 50% identified at age 3 in the European communities
115 (the hearing loss was defined as >150 dB HL for the average of 500, 1000 and 2000 Hz for the better hearing ear) [16]. In contrast, only 15.7% were identified at this age in the investigation published by Ruben and Rozycki [23]. The prevalence rate of congenital/early acquired hearing loss is relatively similar within the western civilization and thus the significant differences may be explained by discrepances in the organization of the health systems and/or to variations in the time periods during which the investigations were performed. However, the differences in the time of threshold identification may also reflect major differences in political, social and cultural backgrounds. In the present investigation 74% of the children were identified at the age of 2 years, which is a significantly higher rate compared with that in the Swedish (56%) and European (30%) investigations and also with the Danish investigation previously mentioned [22]. This can probably be ascribed to the selection of the present material; the limited number of subjects, and the distribution of the degree of hearing impairment in group A (Figs. 2 and 3). Thus, unfortunately, this high rate of identified children at the age of 2 years cannot be considered reliable. The invalidity is further supported by the increased median age at threshold identification in groups B and C. The relationship between the age at hearing threshold identification and the degree of hearing loss (Fig. 3) indicates that hearing losses > 95 dB HL may be unidentified after the age of 1 year. This delayed identification may have serious consequences for the child who is deprived of mandatory training and treatment. However, recommendation of early identification of moderate-to-severe hearing losses (i.,e. 40-80 dB HL as the average of 500, 1000 and 2000 Hz for the better hearing ear) is also required in order to avoid impaired speech and language development [24]. Preliminary results of speech and language characteristics of children with mild hearing losses (i.e. 15-39 dB HL as the average of 500, 1000 and 2000 Hz for the better hearing ear) indicate that on an average the hearing thresholds are identified at age 9.7 years and that also these children have speech and language deficits [9]. The rate of only 50-63% identified at the age of 3 years [14,16,22] indicates that early detection and identification of congenital/early acquired hearing impairment is a serious and as yet unsolved problem and that auditory hearing screening, whatever the method, has largely failed its aim. However, the program concerning early detection and identification set up in G6teborg during the period 1970-1980 has proved that early diagnosis may be improved by intensive information to all parents with new-born babies describing the importance of the hearing organ and informing the parents on where to go if they are worried about their child's hearing ability [14]. The regular child examinations at the general practitioners' during preschool age may improve the rate of identification of hearing impairment [15]. However, these examinations do not seem to contribute to the detection of congenital hearing loss, but they may contribute to early diagnosis of late onset hearing impairment [14].
116
Conclusion T h e p a r e n t s are the first initiators of the i d e n t i f i c a t i o n of their h e a r i n g - i m p a i r e d child, b u t the time o f identification of c o n g e n i t a l / e a r l y acquired h e a r i n g loss is still u n a c c e p t a b l y late in m o s t cases. T o i m p r o v e the early detection, i n f o r m a t i o n on the i m p o r t a n c e of the hearing o r g a n should be given to all p a r e n t s at their child's delivery a n d at regular health c o n t r o l e x a m i n a t i o n s . T h e general p r a c t i t i o n e r s should m a k e careful records t h r o u g h o u t infancy of s o u n d reactions c o m b i n e d with i n f o r m a l testing. T h e c o m b i n a t i o n of i n f o r m a t i o n to the p a r e n t s a n d t h o r o u g h testing at the h e a l t h control e x a m i n a t i o n s m a y facilitate early identification of the h e a r i n g - i m p a i r e d child. F u r t h e r m o r e , e m p h a s i s should be laid on the i m p o r t a n c e of the hearing o r g a n when e d u c a t i n g p e r s o n n e l dealing with infants a n d children, i.e. health visitors, teachers, nurses, medical students, general practitioners, p e d i a t r i c i a n s , etc. T h e s e suggestions together with the m a i n t e n a n c e of o p e n clinics (i.e. no o b l i g a t o r y m e d i c a l referral), m a y result in an earlier identification a n d t r e a t m e n t of hearing loss. In this way d e v e l o p m e n t a l disorders in speech, language, psychological a n d m e n t a l b e h a v i o r m a y be prevented.
Acknowledgement This s t u d y was s u p p o r t e d b y Rosalie Petersen's F o u n d a t i o n .
References 1 Barr, B., Early identification of hearing impairment. In I.G. Taylor and A. Markides (Eds.), Disorders of Auditory Function, Ill, Academic Press, London, 1980, pp. 33-42. 2 Bentzen, O. and Jensen, J.H., Early detection and treatment of deaf children. A European concept. In S.E. Gerber and G.T. Mencher (Eds.), Early Management of Hearing Loss, Grune and Stratton, San Fransisco, 1981, pp. 85-103. 3 Bradford, L. and Roussey, C., Respiration audiometry, Maico Audiol. Library Ser., 10 (1972) 22-24. 4 Downs, M.P. and Sterritt, G., Identification audiometry for neonates. A preliminary report, J. aud. res. 4 (1964) 69-80. 5 Downs, M.P., Auditory screening, Otolaryng. Clin. North Amer, 11 (1978) 611-629. 6 Downs, M.P., Return to the basics of screening. In S.E. Gerber and G.T. Mencher (Eds.), Early Diagnosis of Hearing Loss, Grune and Stratton, New York, 1978, pp. 129-154. 7 Feinmesser, M., Tell, L. and Levi, H., Follow-up of 40.000 infants screened for hearing defect, Audiology, 21 (1982) 197-203. 8 Feinmesser, M. and Tell, L., Neonatal screening for detection of deafness, Arch. Otolaryng., 102 (1976) 297-299. 9 Gershel, J. and Ruben R.J., Preliminary results of speech and language characteristics of children with 15-39 dB hearing loss in the better hearing ear, 1982, Personal communication. 10 Galambos, R. and Depsland, P.-A., The auditory brain stem response (ABR) as a useful diagnostic tool in the intensive care nursery, Pediat. Res., 14 (1980) 154-158. 11 Himmelfarb, M.Z., Popelka, G.R. and Margolis, R.H., Acoustic reflex. Evaluation in neonates. In S.E. Gerber and G.T. Mencher (Eds.), Early Diagnosis of Hearing Loss, Grune and Stratton, New York, 1978, pp. 109-127.
117 12 Hodgson, W.R., Testing infants and young children. In D.R. Katz (Ed.), Handbook of Clinical Audiology (2nd edn.), Williams and Wilkins, Baltimore, 1978, pp. 397-409. 13 Kankkunen, A. and Liden, G., How efficient is high-risk register for identifying children with impaired hearing. In Proc. XV Int. Congr. Audiology, Krakow, 1980 (abstr.). 14 Kankkunen, A., Pre-school children with impaired hearing, Acta. Otolaryng., Suppl. 391 (1982). 15 KShler, L., Health control of four-year-old children, Acta paediatr. Suppl. 235 (1973). 16 Martin, J.A.M., Diagnosis and communicative ability in deaf children in the European Community, Audiology, 21 (1982) 185-196. 18 Mencher, G.T., A program for neonatal hearing screening, Audiology, 13 (1974) 495-500. 19 Parring, A., Etiologisk udredning red horetab hos born, Nord. Med, 97 (1982) 17-19. 20 Parving, A., Elberling, C. and Salomon, G., ECoG and psycho-acoustic tests compared in identification of hearing loss in young children, Audiology, 20 (1981) 365-381. 21 Parring, A. and Elberling, C., Clinical Application of Electrocochleography in Children. In C.G. Chiarenza and D. Papakostopoulos (Eds.), Clinical Application of Cerebral Evoked Potentials in Pediatric Medicine, Exerpta Medica, Amsterdam. 22 Parving, A., Epidemiology of hearing loss and aetiological diagnosis of hearing impairment in childhood, Int. J. pediat. Otorhinolaryng., 5 (1983) 151-165. 23 Ruben, R.H. and Rozycki, D., Diagnostic screening for the deaf child, Arch. otolaryng. 91 (1970) 429-432. 24 Ruben, R.J. et al., Moderate to severe sensorineural hearing impaired child. Analysis of aetiology, intervention and outcome, Laryngoscope, 92 (1982) 38-46. 25 Sarno, C.N. and Clemis, J.D., A workable approach to the identification of neonatal hearing impairment, Laryngoscope, 90 (1980) 1313-1320. 26 Schulman-Galambos, C. and Galambos, R., Brain stem evoked response audiometry in newborn screening, Arch. Otolaryng., 105 (1979) 86-90. 27 Simmons, F.B., Automated screening test for newborns. The crib-o-gram. In J.B. Jaffe (Ed.), Hearing Loss in Children, University Park Press, Baltimore, 1977, pp. 89-98. 28 Stensland-Junker, K., Barr, B., Maliniemi, S. and Wasz-H~Sckert, O. BOEL-screening. A program for the early detection of communicative disorders. Preliminary reports from a study on 1.000 Finnish infants, Audiology, 17 (1978) 51-62.