The last 20 years have witnessed a dramatic change in the way cognitive impairment, particularly dementia, has been seen. Once thought to be a normal aspect of the aging process, the dementias are now perceived to be diseases caused by a variety of etiologies, a minority of which are currently treatable. As reviewed by Barry and Moskowitz1 in this issue of the Archives, studies of reversible dementia have been important because they have brought the issue of potential reversibility to the clinician's attention. However, as Barry and Moskowitz1 emphasize, many of the studies of so-called reversible dementia have significant methodologic flaws that leave many unanswered questions. Should every patient who presents with dementia undergo the same extensive battery of tests? If so, specifically which tests should be ordered? Even when potentially curable causes of the dementia are found, how often does the cognitive disorder
See also p 1914.