A Study of Hearing Aid Fitting Formulas Based on Polynomial Approximation

Wearing hearing aids is one of the effective measures to correct the hearing condition of patients with hearing loss. The choice of the prescription formula is the key to hearing aid gain compensation. DSL-v5 is a commonly used fitting prescription formula, which is designed mainly for pediatric patients. It introduces the Real-Ear-to-Coupler Difference (RECD) test, taking into account the patient's age and hearing threshold, adding an understanding of hearing test methods, hearing aid types, microphone position effects, and hearing assessment with plug-in headphones. To aggregate various factors, this paper proposes a DSL-v5 fitting formula through a least squares-based polynomial fitting method, and verifies the accuracy of this fitting formula by testing experiments. The experiments demonstrate that the fitting formula can well meet the gain compensation needs of adult patients and pediatric patients.