The purpose of this study is to determine whether chin-down posture or use of a thickened liquid diet is more effective in the prevention of aspiration and aspiration pneumonia in patients with Parkinson's disease and/or dementia. Liquid aspiration is the most common type of aspiration in older populations, especially those suffering from debilitation, dementia, and depression. Pneumonia may develop as a consequence of aspiration and is the fifth leading cause of death in the US among persons age 65 years and over. Current treatment involves either use of chin-down position with swallowing or use of thickened liquids in the diet, without any clear evidence supporting the use of one treatment over the other. This is a Phase III inpatient and/or outpatient study in which all participants will be randomly assigned to either the chin-down position or the thickened liquid treatment group based on swallowing function during a modified barium swallow. This study is scheduled to recruit patients for a three-year period; participation by each individual patient spans no more than three months after entry.

Inclusion Criteria:

• Have dementia or Parkinson's disease and are found to aspirate on thin liquid during a set of qualifying swallows.

Exclusion Criteria:

• Have smoked more than a pack of cigarettes per day in the last year.
• Drink more than 3 alcoholic beverages per day on a regular basis.
• Have had any head and neck cancer treatment.
• Have any head and neck anatomic deformities.
• Have a history of 20 years or longer of insulin-dependent diabetes.
• Have other exclusionary neurologic diagnoses.
• Have had pneumonia within 6 weeks of screening.
• Currently have a nasogastric tube.
• Currently have a tracheotomy.
• Are a resident in non-participating nursing home or assisted living environment.
• Live alone.
• Have no regular care provider present at meals.
• Have no Speech-Language Pathologist to provide a 3-month follow-up.