Ammonia Levels and Cognitive Impairment

The purpose and objective of this study is to determine the prevalence of elevated ammonia levels in subjects with cognitive impairment, and to observe if treating the cause of the elevated ammonia level improves mental status. This study does not include any imaging, treatment,or interventions, other than the blood draws. The blood draws will be taken to assess blood ammonia level and liver function. If the the ammonia level is not elevated, no further lab draws will occur. If the ammonia level is elevated, liver function is normal, and a cause for the high ammonia level is revealed with a plan for clinical treatment by the subjects' physician, then two more blood draws will occur; one prior to treatment, and one 3 months after treatment. The main risk to subjects is related to the blood draw (i.e. momentary discomfort, bruising, infection, bleeding, clotting or fainting), and there is a potential loss of confidentiality. A paired student t test will be done with the two later blood to compare objective data.