Gastroparesis symptom score improvement to (all subjects). GP symptom score improvement in subjects whose gastric electrical stimulation (GES) parameters are associated with left and/or right vagal fiber activation compared to those without the same type of vagal response (N = 66 subjects). Specifically, left vagal Aγ and B fibers, along with right vagal Aβ, Aδ and B fibers, were strongly associated with subjects reporting lower symptom scores on their GCSI survey, warranting further investigation into the role of these vagal responses in the mechanisms of GES therapy. Considering all of the symptom types and fiber groups, GES-evoked vagal activity was almost universally associated with subjects reporting lower symptom score ratings. Data are reported as mean difference in symptom scores ± s.e.m.