Oropharyngeal Sensory Stimulation in Healthy Older Adults

Swallowing is a complex behaviour that is processed within an integrated neural network which includes a prominent sensory component. While previous research has suggested that sensory stimulation applied to the peritonsillar region can evoke swallowing, the range of stimuli that are effective in facilitating swallowing has not been fully explored.

OBJECTIVE:

To determine the effect of oropharyngeal air-pulse stimulation on the frequency of saliva swallowing in healthy geriatric individuals.

METHODS:

Thirteen (mean age = 73.8 yrs) healthy volunteers (7 males) with no history of swallowing, orofacial, respiratory, or neurologic problems were recruited for this study. Swallowing frequency was monitored across five conditions: baseline (no stimulation), unilateral right oropharyngeal stimulation, unilateral left oropharyngeal stimulation, bilateral oropharyngeal stimulation, and sham oropharyngeal stimulation. Swallows were identified by laryngeal and respiratory movement patterns. Air pulses were delivered to the oropharynx via small bore tubing embedded within a mouthpiece made of dental resin.

RESULTS:

Repeated measures ANOVA revealed a significant main effect of stimulation on swallowing frequency (p<0.05). Multiple pairwise comparisons indicated that swallowing frequency (swallows/min) was significantly greater during bilateral oropharyngeal stimulation (1.03 ± 0.89; mean, SD) than during the baseline (0.49 ± 0.47; p<0.005). Increases in swallowing frequency associated with unilateral right, and unilateral left, oropharyngeal stimulation, approached significance (p=0.006; right: 0.81 ± 0.68; left: 0.87 ± 0.82).

CONCLUSION:

These findings suggest that oropharyngeal sensory stimulation can facilitate saliva swallowing in older adults, corroborating our previous findings in young adults (Theurer et al., 2005). Oropharyngeal air-pulse stimulation may have clinical utility in the treatment of individuals with swallowing impairments who experience delayed triggering of the pharyngeal swallow.

ACKNOWLEDGEMENTS:

This research was supported by a Focus-on-Stroke Doctoral Research Award (HSFO, CIHR, CSN, Astra Zeneca) to JAT, and HSFO, CIHR-POP, PREA and UWO-WIF funding to REM.