Synonyms for Convulsive (same or very similar meaning)
WordNet sense 1 (acting with or marked by or resulting from great force or energy or emotional intensity):
violentWordNet sense 2 (affected by involuntary jerky muscular contractions; resembling a spasm):
spasmodicWordNet sense 3 (subject to change or variation):
unsteadyFrom the ODE community, based on WordNetadd/edit