Optimizing digital ear canal scanning protocols for hearing aid acoustics: Balancing efficiency and accuracy in clinical practice

The digitization of ear canal impression processes has transformed hearing aid acoustics, with over 90% of laboratories now employing digital manufacturing for earmolds. However, the optimal balance between scan efficiency and accuracy remains underexplored in clinical practice. In the present study the reproducibility of ear canal scans across three protocols varying in duration of the scans short (30–60 s), medium (70–120 s), and comprehensive (140–210 s) was investigated. Shorter scan times resulted intentionally in missing data in the digital surface. Using an idealized Standard Triangle Language (STL) model as a reference geometry, intra-individual repetitive measurement series with consecutive scans per protocol were conducted by different investigators. Statistical analysis included descriptive metrics, normality testing, and non-parametric group comparisons. The results indicate high consistency across all protocols, with mean deviations below 0.2 mm, which is well within the tolerances of additive manufacturing. The short protocol exhibited the largest variability (mean –0.11 mm, SD: 0.05 mm), while medium (mean –0.05 mm, SD: 0.02 mm) and comprehensive (mean –0.04 mm, SD: 0.02 mm) protocols showed negligible differences. These findings demonstrate that scan durations as brief as 30–60 s preserve practical accuracy, enabling efficient clinical workflows without compromising precision. The study provides empirical evidence for optimizing digital scanning protocols in hearing aid fitting, addressing a critical gap in audiologic practice.