Symmetry and reproducibility of swallowing sounds.

Cervical auscultation is being used more frequently in the clinical assessment of dysphagic patients. The present study was designed to assess symmetry and the reproducibility of swallowing sounds detected simultaneously from bilateral cervical sites. Symmetry of the swallowing sounds acquired using our method was verified because no significant differences were found for any parameters in both time and frequency domain analyses between swallowing sounds detected bilaterally. This result supports the use of a "unilateral" site for the detection of swallowing sounds. The reproducibility of swallowing sounds was assessed by a coefficient of variation. Results of this analysis suggest that one should evaluate the acoustic characteristics of swallowing sounds from repeated swallows rather than from one swallow.