Screening for sensorineural deafness by health visitors

Screening for hearing loss in the first year of life, using the distraction test, remains the responsibility of health visitors in most health districts in the United Kingdom. We have evaluated the screening procedure used routinely in one health region in a population of infants at increased risk of sensorineural deafness. They were infants who weighed less than 2000 g at birth or infants who weighed 2000 g or more at birth and who spent more than 24 hours in a special care nursery. The infants' responses to a distraction test were recorded by health visitors and sent to the project office. The results were compared with information from a regional register of early childhood impairment that included children in whom sensorineural deafness had been diagnosed before the age of 3 years. The register had been compiled using information from a wide range of sources. When used in this high risk population the distraction test was sensitive (91%), but nonspecific (82%). The effectiveness of the screening programme was limited, however, because there was an increased risk of deafness among infants who missed being screened by health visitors. In addition, 71% of the deaf infants on the register were not in the high risk population. Oxford Region Child Development Project, John Radcliffe Hospital, Oxford OX3 9DU Ann Johnson National Perinatal Epidemiology Unit, Oxford Hazel Ashurst Steering Conunittee, Oxford Region Child Development Project J Catterson M Goldacre R King A J Macfarlane J-A Macfarlane A Turnbull A Wilkinson Correspondence to: Di Johnson. Accepted 15 March 1990 Despite considerable advances in techniques for the screening of newborn infants for sensorineural deafness, screening for hearing loss still remains the responsibility of health visitors, who use the distraction test when the children reach the age of 6-8 months. There is evidence that this technique lacks sensitivity, and deaf children may be missed.' 2 The test also has a low specificity for sensorineural deafness, a large number of children having false positive results.3 ' Although some of these children will have a conductive hearing loss, it is expensive to retest or refer the infants who fail the test, and the parents become anxious. Although the test is used by health visitors throughout the country,5 few health districts systematically collect information on test results and relate these to the hearing of the children.6 This means that a test of doubtful validity is being applied to thousands of infants each year with little attempt to evaluate either its accuracy in detecting deaf children or the effectiveness of programmes that include it. We have studied the use of the distraction test in a population of infants considered to be at Steering Committee, Oxford Region Child increased risk of sensorineural deafness. By comparing test results against cases of sensorineural deafness identified from a regional register of impairment that was compiled concurrently, we have assessed the accuracy of the test, and have identified factors that limit the effectiveness of a community based hearing screening programme. Subjects and methods A subpopulation of infants considered to be at particular risk of sensorineural deafness were identified. They were infants born to mothers resident in the Oxford region in 1984 and 1985 who weighed less than 2000 g at birth, or who weighed 2000 g or more and spent longer than 24 hours in a special care nursery. Infants were identified by telephoning all 10 special care nurseries in the region once a week. Infants weighing less than 2000 g at birth who were not admitted to special care nurseries or who were born outside the region were identified from birth registration data. Information about infants weighing 2000 g or more who were admitted to special care nurseries outside the region was provided by health visitors. Parents' consent for the transfer of information on the results of screening tests from the health visitor to the project office was sought at the time of discharge from the nursery; an 'opting out' approach was used.7 Health visitors were asked to apply the distraction test to this subpopulation using the technique routinely taught in their district. The birth history of each infant was known to the health visitor before testing. We had noticed some variations in technique and the timing of tests, and these have been described previously.8 In two districts the test is routinely carried out at the age of 7 months, and in six districts at the age of 8 months. We asked health visitors to test at the age selected by their district and not to make any correction for gestational age at birth. Results of the tests were recorded on a simple form and sent to the project office. Health visitors continued to screen the remaining infants in the population routinely, but the results of these screening tests were not available to us. We asked health visitors to retest infants or refer infants for a specialist opinion whenever they considered it was necessary. If the infant did not turn to a sound made at one or both ears, this was regarded as a failure. In general, health visitors retested infants who had failed one test. Infants were usually referred after two 841 group.bmj.com on June 25, 2017 Published by http://adc.bmj.com/ Downloaded from