Update on clinical trials in Dysphagia.

Randomized clinical trials (RCTs) are often known as the gold standard in treatment efficacy studies. This article defines the characteristics of RCTs and the factors that investigators must consider in designing clinical trials in dysphagia. Design issues unique to behavioral treatments often used in dysphagia are discussed. Ongoing RCTs in dysphagia are described including studies of (1) the effectiveness of the Shaker exercise versus standardized treatment in patients with severe dysphagia resulting from stroke or treatment for head and neck cancer who have been nonoral for at least three months; (2) the comparative effects of nectar- and honey-thickened liquids versus chin tuck posture and in patients with dementia or Parkinson's disease with or without dementia who aspirate on thin liquids; and (3) the comparative effects of muscle exercise versus sensory postural therapy for dysphagia resulting from treatment for head and neck cancer. Issues in generalizing from the results of clinical trials are also described.