Guidelines for Medical Investigation of Bilateral Severe to Profound Permanent Deafness in Childhood.
The British Association of Audiological Physicians (BAAP)
The British Association of Community Doctors in Audiology (BACDA)
Mac Ardle BM, Fonseca SJ.
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Contents:
 The role of a community doctor in audiology.
BACDA membership and work.
EARly audit.
School hearing screening survey.
Training and publications.
Connections with other professional bodies.
BACDA study day, CMV and hearing loss, January 2006.
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Background
Advances in genetics, improvements in imaging techniques and changes in the epidemiology of childhood deafness have influenced how we investigate children with hearing impairment.
Clinical guidelines are an integral component of clinical governance (1) and practice may be improved by robust evaluation of guidelines (2). Guidelines are ' systematically developed statements to assist decisions about appropriate care for specific clinical circumstances' (3) based on systematic reviews of research literature. They are not intended to restrict clinical freedom, but practitioners are expected to use the recommendations as a basis for their practice. Local resources and the circumstances and preferences of individual patients also need to be taken into account.
The NDCS states that "Families must be offered the opportunity for their deaf child to have aetiological investigations. These investigations must be carried out in accordance with local protocols based on nationally agreed standards" (4).
A BAAP working group on evidence-based recommendations for the investigation of newly diagnosed children with bilateral severe and profound permanent hearing impairment developed a set of guidelines. These were agreed by BACDA in 2002 and can be viewed on the BAAP website www.baap.org.uk. These recommendations are relevant to all professionals in Audiology, deaf children and their families. Where possible recommendations are based on and linked to the evidence that supports them.
These guidelines will be reviewed in September 2002.
There are several reasons why it is important to investigate deafness
To try and answer parents who ask, "Why is my child deaf?"
To identify and manage co-exisiting medical conditions such as Jervell and Lange-Nielsen syndrome, Alport's syndrome, Neurofibromatosis type 2, Ushers Syndrome and vestibular hypofunction
To assist the family when making decisions about the most appropriate managenent strategy for their child as regards communication mode, educational placement and cochlear implantation
To inform genetic counseling
To inform epidemiological data
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Aims
The aim of these guidelines is to propose a rational approach to the medical investigation of bilateral severe to profound permanent deafness children.
Subjects
All children with bilateral permanent hearing loss and thresholds over 70 dB in the better ear averaged across 500, 1000, 2000 and 4000Hz.
Guidelines for Good Practice
Level 1 investigations
Level 1 investigations should be considered for every child. Timing will depend on several factors, including the family's readiness to proceed with tests, availability of local test facilities and the child’s ability to cooperate with tests.
Paediatric history:
detailed history of pregnancy, delivery and postnatal period
developmental milestones including speech, language and motor milestones
pre and post natal exposure to noise
ototoxic medications
severe head injury
ear disease
meningitis
viral illness
immunisation status
Family history of deafness or risk factors associated with hearing loss in first and second degree relatives
Clinical Examination:
inspection and physical measurement of craniofacial region
examination of the neck, skin and nails, limbs, chest and abdomen
Developmental assessment
Family audiograms: on 1st degree relatives (5)
Electrocardiography (ECG): for prolongation of the (corrected) QT interval (6)
Ophthalmological assessment:
assessment of visual acuity and fundoscopy
discussion of electro-retinography with ophthalmologist if motor milestones are delayed (7, 8, 9, 10)
Urine examination (labstix) for microscopic haematuria (11, 12, 13)
Blood test for Connexin 26 mutation (14, 15, 16, 17)
MRI of Internal Auditory Meati or CT Scan of Petrous Temporal Bone (18, 19, 20)
Level 2 investigations
Level 2 investigations will be indicated from history and clinical findings. As with level 1 investigations, timing will depend on the family's readiness to proceed with tests, availability of local test facilities and how well the child can cooperate with tests.
Serology:
to exclude congenital infection
to include maternal stored (booking) serum
Haematology and Biochemistry where clinically indicated
Thyroid Tests:
family history of thyroid disease
goitre present
Immunology Tests where clinically indicated
Metabolic Screen on blood and urine: where clinically indicated
Renal ultrasound:
if child has preauricular pits or sinuses, branchial cleft or cysts
Mondini defect on imaging
Clinical photography
Chromosomal studies:
history of developmental delay
dysmorphic features
Referral to Clinical Geneticist especially if the parents are consanguineous
Vestibular investigations
What next?
These guidelines will be reviewed by the working group* in September 2002. The revised version will be printed and distributed to clinicians. It is our intention to conduct a fully funded national audit of practice by BAAP and BACDA members in 2003-2004. Please send your comments to Dr B MacArdle or Dr S Fonseca.
*Working Group Members: Dr D Bamiou, Dr M Bitner-Glindzicz, Dr S Fonseca, Dr B Mac Ardle, Dr K Rajput.
breege.macardle@rfh.nthames.nhs.uk
sjfonseca@hotmail.com
References
1. Clinical Governance: Quality in the new NHS . HSC 1999/065.
2. Littlejohns P, Humphris D, eds. How effective are clinical guidelines in implementing clinical guidelines: a practical guide. Abingdon: Radcliffe Medical Press, 1999
3. Committee to Advise the Public Health Service on Clinical Practice Guidelines. Field MJ, Lohr KN, eds. Clinical Practice Guidelines: Directions for a new Program. Washington DC. National Academy Press 1990.
4. Quality Standards in the Early Years: Guidelines on working with deaf children under two years old and their families. NDCS 2002.
5. Stephens D (2001) Audiometric investigation of first- degree relatives. In: Martini A, Mazzoli M, Stephens, D, Read A, ed. Definitions, Protocols & Guidelines in Genetic Hearing Impairment. London: Whurr Publishers, 32-33.
6. Bitner-Glindzicz M, Tranebjoerg L. The Jervell and Lange-Nielsen Syndrome. Adv Otorhinolaryngol 2000; 5645-5652.
7. Calzolari E, Sensi A, Gualandi F (2001) Protocol for syndromal disorders associated with hearing loss. In: Martini A, Mazzoli M, Stephens, D, Read A, ed. Definitions, Protocols & Guidelines in Genetic Hearing Impairment. London: Whurr Publishers, 50 - 71.
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10. Young NM, Mets MB, Hain TC. (1996) Early diagnosis of Usher syndrome in infants and children. American Journal of Otology: 17(1): 30-4.
11. Pajari H, Kaariainen H, Muhonen T, Koskimies O. (1996) Alport's syndrome in 78 patients: epidemiological and clinical study. Acta Paediatrica. 85(11): 1300-6.
12. Flinter F. (1997) Alport's syndrome. Journal of Medical Genetics; 34: 326-330.
13. Wester DC, Atkin CL, Gregory MC. (1995) Alport syndrome: Clinical Update. Journal of the American Academy of Audiology; 6: 73-79.
14. Mueller R (2001) Connexin 26 (GJB2) deafness homepage (URL: http://www.iro.es/cx26deaf.html editors - X Estivill, P Gasparini, N Lench) In: Martini A, Mazzoli M, Stephens, D, Read A, ed. Definitions, Protocols & Guidelines in Genetic Hearing Impairment. London: Whurr Publishers, 176 -180.
15. Lench NJ, Houseman M, Newton V, Van Camp G, Mueller RF (1998) Connexin 26 mutations in sporadic non-syndromal sensorineural deafness. Lancet 351:415.
16. Denoyelle F, Weil D, Maw MA, Wilcox SA, Lench NJ, Allen- Powell DR, Osborn AH, Dahl H-HM, Middleton A,Houseman MJ, Dode C, Marlin S, Boulila-ElGaied A, Grati M, Ayadi H, BenArab S, Bitoun P, Lina-Grande G, Godet J, Levillers J, Garabedian EN, Mueller RF, Gardner RJM, Petit C (1997) Prelingual deafness high prevalence of a 30 delG mutation in the connexin 26 gene. Human Molecular Genetics 6: 2173-7.
17. Kessell DP, Dunlop J, Lench NJ, Liang JN, Parry G, Mueller RF. Leigh IM (1997) Connexin 26 mutations in hereditary non-syndromic, sensorineural hearing deafness. Nature 387: 80- 83.
18. Bamiou D, Worth S, Phelps P, Sirimanna T, Rajput K (2001) Eighth Nerve Aplasia and Hypoplasia in Cochlear Implant Candidiates: The Clinical Perspective. Otology and Neuro-otology; 22: 492-496.
19. Bamiou D, Phelps P, Sirimanna T. Temporal bone computed tomography findings in bilateral sensorineural hearing loss Archives of Diseases in Childhood, 82(3): 257-60, 2000.
20. Antonelli PJ, Varela AE, Mancuso AA. (1999) Diagnostic yield of high-resolution computed tomography for paediatric sensorineural hearing loss. Laryngoscope 109; 1642-1647.