Aspiration: cause and implications.

The purpose of this investigation was to determine the overall prevalence of aspiration in dysphagic individuals referred for a modified barium swallow and the underlying anatomic and/or physiologic causes. A total of 166 patients were seen during a 1-month period at 5 participating institutions. Aspiration was detected in 51.2% of the patients. The most common causes were decreased laryngeal elevation and delayed triggering of the pharyngeal motor response. A history of aspiration pneumonia was significantly associated with the presence of aspiration on modified barium swallow study. The presence of a protective cough was present in only 53% of patients who aspirated, reinforcing the need for appropriate radiologic assessment in patients with suspected dysphagia.