Descending weakness associated with areflexia and ophthalmoplegia is characteristic of botulism. Foodborne botulism is seen 12-38 hours after ingestion of preformed botulism toxin and the first neurologic symptoms involve the cranial nerves. If EMG is performed, repetitive nerve stimulation (RNS) at 50 Hz will show an incremental response of compound muscle action potentials (CMAPs).