Hearing instrument fittings of pre-school children: do we meet the prescription goals?

Verifying the match to prescribed electro-acoustic performance is essential in a scientific approach to pediatric hearing instrument fittings. This study aimed to compare hearing instrument output values, at 65 and 90 dB sound-pressure level (SPL) input signals, of instruments fitted to pre-school children in South Africa to the targets prescribed by the DSLm [i/o] (version 5.0) across the frequency range. Outputs of 31 BTE hearing instruments (20 children, 3-6 years) were verified using coupler-based SPL measurements and measured real-ear-to-coupler differences (RECDs). Results revealed that most of the hearing instrument fittings (regardless of the degree of hearing loss) did not match the prescribed targets. Only 25% of the fittings matched three or more output targets at 65 dB SPL input signal. Output values at 90 dB SPL input signal were far below the prescribed targets. It can be concluded that the lack of a systematic evidence-based approach might lead to inconsistent hearing instrument fittings. Findings may be used to educate clinicians to ensure optimal pediatric hearing instrument fittings.