Reevaluation of the Standard Value for the FraMatrix Test under the Usual Working Conditions of Hearing Aid...

This study aims to reevaluate the reference value of the FraMatrix test under routine administration conditions used by hearing aid specialists. The reference value currently in use (SRT50 = -6.0 dB signal-to-noise ratio [SNR]) was established under conditions that differ substantially from those encountered in clinical practice. In routine assessments, hearing aid specialists administer three lists of 20 sentences in free field (FF), retain the result of the final list, and present the word lists in an open-set condition (i.e., patients are not informed of all possible target words). In contrast, the existing reference value was derived under monaural headphone conditions, following 40 lists of 10 sentences, and using a closed-set condition. Developing a standard value suitable for clinical practice is important, as reimbursement for hearing aids depends on it.

A total of 44 normal-hearing subjects completed the FraMatrix test under conditions similar to those used in clinical settings: binaurally in FF, in an open-set condition, after two training lists. Monaural results using headphones were also collected.

In FF, the average SRT50 value is -5.1 dB, with a 95% confidence interval around the mean of [-5.5; -4.7] dB, and a median of -5 dB. This speech-in-noise performance is statistically and clinically poorer than the standard value used until now. This difference is likely to be attributed to the distinct testing conditions between our study and the study that established the current standard value. In the latter, participants were considerably more trained, having completed 400 sentences (40 lists) in a closed-set condition, whereas our subjects completed only 60 sentences (3 double lists) in an open-set condition. However, we cannot exclude another possible explanation for this discrepancy: calibration differences between the transducers used in our study and those used in the study that established the current standard value.

When taking the FraMatrix test under clinical conditions (FF, open-set, after two double training lists), we recommend adopting a new standard value of -5.1-dB SNR, accompanied by the 95% confidence interval to support clinical interpretation. This updated value is more representative of the conditions under which hearing aid specialists administer the test and enables a more accurate assessment of auditory performance in noisy environments.