Randomised and quasi-experimental trials that compared neuromuscular electrical stimulation (using electrodes placed on the anterior neck) with traditional therapy in adults with dysphagia of any cause were eligible for inclusion. Traditional therapy was defined as a combination of diet modification, position adjustment, effortful swallowing and training to use gestures that enhanced airway protection during swallowing.
More than half the included studies involved patients with dysphagia following stroke; other causes of dysphagia were Parkinson's disease, head and neck cancer and radiation damage. Duration of dysphagia, where reported, ranged from 20 days to more than a year. Neuromuscular electrical stimulation was typically given for one hour/day for 10 to 20 sessions (where reported). Various outcome measures were used.
Two reviewers independently selected studies for inclusion. Disagreements were resolved by discussion or by consulting a third reviewer.