Andrea Santamato, Francesco Panza, Vincenzo Solfrizzi, Anna Russo, Vincenza Frisardi, Marisa Megna, Maurizio Ranieri, Pietro Fiore
DOI: 10.2340/16501977-0384

Objective: To perform acoustic analysis of swallowing sounds, using a microphone and a notebook computer system, in healthy subjects and patients with dysphagia affected by neurological diseases, testing the positive/negative predictive value of a pathological pattern of swallowing sounds for penetration/aspiration.
Design: Diagnostic test study, prospective, not blinded, with the penetration/aspiration evaluated by fibreoptic endo­scopy of swallowing as criterion standard.
Subjects: Data from a previously recorded database of normal swallowing sounds for 60 healthy subjects according to gender, age, and bolus consistency was compared with those of 15 patients with dysphagia from a university hospital referral centre who were affected by various neurological diseases.
Methods: Mean duration of the swallowing sounds and post-swallowing apnoea were recorded. Penetration/aspiration was verified by fibreoptic endoscopy of swallowing in all patients with dysphagia.
Results: The mean duration of swallowing sounds for a liquid bolus of 10 ml water was significantly different between patients with dysphagia and healthy patients. We also described patterns of swallowing sounds and tested the negative/positive predictive values of post-swallowing apnoea for penetration/aspiration verified by fibreoptic endoscopy of swallowing (sensitivity 0. 67 (95% confidence interval 0. 24–0. 94); specificity 1. 00 (95% confidence interval 0. 56–1. 00)).
Conclusion: The proposed technique for recording and measuring swallowing sounds could be incorporated into the bedside evaluation, but it should not replace the use of more diagnostic and valuable measures.