Prescriptive Target Matching Across Hearing Aid Technology Generations: A Real-Ear Insertion Gain Analysis

Background: Advances in hearing aid technology may improve prescriptive target matching, but whether newer devices better match targets remains unclear. This study compared prescriptive target matching across hearing aid technology generations. Methods: This secondary analysis included 29 flagship prescription hearing aids grouped into older (2021-2022; n = 8), mid (2023; n = 11), and newest (2024-2025; n = 10) technology generations. Root Mean Square Error (RMSE) between measured Real Ear Insertion Gain (REIG) and NAL-NL2 targets was calculated across six frequencies (500-6300 Hz) for soft (55 dB SPL), conversational (65 dB SPL), and loud (75 dB SPL) speech levels under Initial Fit and Tuned Fit conditions. Kruskal-Wallis tests and linear mixed-effects models accounting for manufacturer clustering were used to evaluate prescriptive target matching across technology generations. Results: No significant technology-generation differences were observed at Initial Fit. Following tuning, group comparisons showed differences at conversational (p = 0.006; ε² = 0.321) and loud (p = 0.004; ε² = 0.347) levels, with a directionally consistent but non-significant difference at soft speech (p = 0.055; ε² = 0.146). After accounting for manufacturer clustering, release year remained a significant predictor of closer target matching only at conversational speech (β = -0.15 dB/year, 95% CI [-0.29, -0.01], p = 0.048). Sensitivity analyses supported the robustness of this finding. Conclusions: Newer hearing aids showed closer prescriptive target matching following tuning at conversational speech, although effects at soft and loud speech did not survive adjustment. Technological advances may improve prescriptive target matching at conversational input levels during fitting.