Electrical stimulation of salivary flow in patients with Sjögren's syndrome

Patients with the salivary component of Sjögren's syndrome (SS) develop chronic xerostomia, which causes oral symptoms and functional impairment in approximate proportion to its severity. The purpose of this double-blind study was to determine whether an electrical stimulus applied to the tongue and hard palate by a battery-operated device (SAL II, Biosonics, Inc.) could stimulate salivary flow in subjects with generally severe SS. Twenty-nine patients with the salivary component of SS (diagnosed as the presence of focal chronic sialadenitis in a labial salivary gland biopsy specimen with a focus score of greater than 1 focus/4 mm2) were randomly assigned active or placebo devices, which they used for three minutes, three times a day for four weeks. Whole saliva flow rates were measured at weeks 0, 2, and 4 by collection of whole saliva both before and after stimulation with the device. Twenty-four subjects completed the study. The change in mean post-stimulation flow rate from week 0 to week 4 was greater for the 13 subjects using an active device (0.08 +/- S.D. 0.08 g/2 min, to 0.24 +/- 0.33 g/2 min) than for the 11 subjects using a placebo device (0.11 +/- 0.15 g/2 min, to 0.08 +/- 0.18 g/2 min) (p = 0.04). However, the magnitude of the mean difference was small, because three subjects using active devices responded and others did not. Only five subjects, all using active devices, reported a subjective increase in the amount of their saliva. The results of this study indicate that some SS patients with residual salivary flow show a significant response to electrical stimulation, but others with low or absent whole saliva flow rates do not respond.