RESUMO
BACKGROUND AND OBJECTIVES: Although popular as a method for aural rehabilitation with hearing impairment, hearing aids are susceptible to inflow of foreign materials such as water, sweat, and dust, causing corrosion of the circuit board and eventual device failure. Performance of hearing aids is evaluated by assessing the applicability of hydrophobic nano-coating technique using waterproof hearing aids electronic devices. SUBJECTS AND METHOD: Performance was evaluated using a Fonix 7000 for the maximum output sound pressure level (Max OSPL 90), high frequency average full on gain (HFA FOG), total harmonic distortion and input noise level for 13 hearing aids. Nine of the 13 hearing aids were tested after nano-coating was applied to 2.5 µm of thickness. Fro the immersion test, hearing aids were subjected to 1 m of depth of water and performance was immediately measured; they were also measured after a day and also after a month. RESULTS: In the coated group, Max OSPL 90, HFA FOG were significantly reduced but the corrosion of the circuit board was not observed. The four hearing aids without nano-coating failed to work immediately after the immersion test. However, there were no changes in performance after a month of immersion in any of the aids. For the non-coated group, corrosion of the circuit board was observed after 1 month. CONCLUSION: Nano-coating is a competitive technology and an advangtage to have to ensure waterproof effect and corrosion prevention. Thus it should be recognized as essential technology to enhance performance of hearing aids.