A Novel Method for the Nonradiological Assessment of Ineffective Swallowing

Abstract

This validation study evaluates a new manometry impedance-based approach for the objective assessment of pharyngeal function relevant to postswallow bolus residue. We studied 23 adult and pediatric dysphagic patients who were all referred for a videofluoroscopy, and compared these patients with 10 adult controls. The pharyngeal phase of swallowing of semisolid boluses was recorded with manometry and impedance. Fluoroscopic evidence of postswallow bolus residue was scored. Pharyngeal pressure impedance profiles were analyzed. Computational algorithms measured peak pressure (Peak P), pressure at nadir impedance (PNadImp), time from nadir impedance to PeakP (PNadImp-PeakP), the duration of impedance drop in the distal pharynx (flow interval), upper esophaghageal sphincter (UES) relaxation interval (UES-RI), nadir UES pressure (NadUESP), UES intrabolus pressure (UES-IBP), and UES resistance. A swallow risk index (SRI) was derived by the formula: SRI=(FI × PNadImp)/(PeakP × (TNadImp-PeakP+1)) × 100. In all, 76 patient swallows (35 with residue) and 39 control swallows (12 with residue) were analyzed. Different functional variables were found to be altered in relation to residue. In both controls and patients, flow interval was longer in relation to residue. In controls, but not patients, residue was associated with an increased PNadImp (suggestive of increased pharyngeal IBP). Controls with residue had increased UES-IBP, NadUESP, and UES resistance compared with patients with residue. Residue in patients was related to a prolonged UES-RI. The SRI was elevated in relation to residue in both controls and patients and an average SRI of 9 was optimally predictive of residue (sensitivity 75% and specificity 80%). We present novel findings in control subjects and dysphagic patients showing that combined manometry and impedance recordings can be objectively analyzed to derive pressure-flow variables that are altered in relation to the bolus residual and can be combined to predict ineffective pharyngeal swallowing.