Abstract
Many studies evaluate dysphagia in elderly patients and compare their swallowing to younger controls to assess the degree of swallowing impairment. Previous research suggests that changes should be expected in swallowing due to aging, and these changes need to be considered when performing swallowing assessments. A systematic review was conducted to elucidate the timing of swallowing in healthy. A comprehensive multiengine literature search was conducted to find articles studying swallowing in the healthy elderly, which yielded 22,852 articles of which 11 were judged to be relevant. Only articles using videofluoroscopy as an assessment method for swallowing timing were included. The articles underwent detailed review for study quality and data extraction. The eleven studies contained data for 32 different parameters, and 10 of the 11 studies compared elderly subjects to a younger group. Timing measures from the studies were compiled for analysis. In general, bolus transit times do not appear to change with age. Of note, elderly subjects tended to have a significantly delayed swallow response times and longer duration of upper esophageal sphincter opening. Results showed a large degree of variability across studies for each of the timing measures. Confidence intervals for timing in healthy older participants were computed across studies. Potential sources of variation were identified, including methodological, stimulus-related and participant-related sources. The results suggests that aging affects only a few very specific swallowing timing parameters, and many parameters appear to be unaffected by aging. Therefore, significant differences from a young reference sample should be interpreted as dysphagia rather than normal changes due to aging.