Comparison of the Utility of Single-Ear and Binaural Auscultations: A Diagnostic Accuracy Study

Single-ear (monaural) auscultation is occasionally used in lung examinations. In this method, a binaural stethoscope is placed in one ear, leaving the other ear free for listening to other sounds. To enhance the efficiency of medical examinations, interviews, and auscultation are sometimes performed simultaneously using single-ear auscultation. However, there are no studies reporting the accuracy of single-ear auscultation for lung examinations. Therefore, this study aimed to compare the utility of single-ear and binaural auscultations.

We prospectively collected data from 35 respiratory physicians at Fukujuji Hospital and Kyorin University Faculty of Medicine from April 2024 to June 2024. Data on audible minimal volume, points earned from auscultation questions, and self-reported confidence levels for answers to auscultation questions were compared between single-ear and binaural auscultations in both quiet and noisy environments. Furthermore, participants were divided into those with a respiratory specialist qualification (specialist group) and those without the qualification (nonspecialist group), and subanalysis was performed between these two groups.

Single-ear auscultation resulted in fewer earned points than binaural auscultation in both quiet environments (median 12 points (range 7-15) vs. 13 points (9-16), p<0.001) and noisy environments (median 12 points (range 5-16) vs. 13 points (8-16), p=0.008). The average self-reported confidence levels were also lower for single-ear auscultation (quiet environment: p<0.001; noisy environment: p<0.001). The average audible minimal volume was not different between the single-ear and binaural auscultations (quiet environment: p=0.814; noisy environment: p=0.051). Twenty-three participants (65.7%) scored 1 or more points higher during binaural auscultation than during single-ear auscultation in both environments. There was no difference between the respiratory specialists and nonspecialists in the number of participants exhibiting advantages during binaural auscultation or in the difference in average audible minimal volume, earned points from auscultation questions, or average self-reported confidence levels for answers to auscultation questions between single-ear and binaural auscultations.

The utility of single-ear auscultation for lung auscultation was less than that of binaural auscultation. Physicians should use a binaural stethoscope correctly and listen with both ears.