Identification of childhood hearing impairment in Uusimaa County, Finland.

The purpose was to report the identification age of the hard-of-hearing children born between 1 January 1973 and 31 December 1990. The subjects comprised all children (353) fitted with hearing aid in an age-matched target population of 270 726 persons in Uusimaa County including Helsinki. The age of identification was studied in three groups; pure tone average (0.5, 1 and 2 kHz) > or = 30 dB, > or = 35 dB and > or = 50 dB HL enabling comparison with the identification ages reported in the literature. In the first group the median identification age was 3.6 years (mean 4.2), in the second 2.9 years (mean 3.8) and in the third 2.1 years (mean 2.8). The first group was identified significantly later than the third one (P = 0.004). The second group differed from the third significantly in detection age as well (P = 0.004). The severity of hearing impairment correlated highly with the detection age (r = -0.69. P < 0.0001). The data clustered at the ages of 1-2.5 years (hearing level 90-120 dB) and at 4-8 years (30-60 dB).