Monaural and binaural speech-recognition curves for the freiburg monosyllabic speech test in quiet.

Objective: Determination of monaural and binaural speech-recognition curves for the Freiburg monosyllabic speech test (FMST) in quiet to update and supplement existing normative data.

Design: Monaural and binaural speech-recognition tests were performed in free field at five speech levels in two anechoic test rooms at two sites (Lübeck and Oldenburg, Germany). For the monaural tests, one ear was occluded with a foam earplug.

Study sample: 40 young participants (30 females) aged between 18 and 25 years (Mean: 22.0 years) with German as their first language were included. All participants were otologically normal according to ISO 8253-3.

Results: No asymmetries were found between the left and right ears. Significant differences were observed when compared to the original monaural curve defined in DIN 45626-1 obtained with headphones. In addition, a binaural speech-recognition curve was measured. The results indicate that the binaural curve is highly sensitive to perturbation.

Conclusion: While the newly obtained monaural curve is moderately consistent with existing normative data, verification remains essential to ensure quality and reliability. Establishing a binaural reference curve is long overdue. Although site-specific differences led to some ambiguity regarding the binaural advantage, a binaural advantage of 3 dB is proposed for the FMST in quiet.