Assessment of cognitive impairment, alzheimer’s disease, and other forms of dementia

This chapter updates reviews of methods and techniques related to recognition of cognitive impairment and the progressive steps involved in diagnosing dementia, from screening tests to clinical assessment. Diagnostic criteria for “minor” and “major” neurocognitive disorders are outlined, as well as the typical progressive presentation of dementia over the full course, most typically seen with Alzheimer’s disease. The clinical evaluation of the patient with cognitive impairment is presented in detail, including central parts of the dementia assessment, starting with the physical and neurological examination, including brief cognitive tests, laboratory evaluation, genetic testing, and brain imaging, as well as aspects of the neuropsychological assessment. In the differential diagnosis, numerous pathogenic factors can impair mental processing. The most common problem is the consideration of Alzheimer’s disease, which must be evaluated relative to treatable conditions and distinguished from conditions which can have a similar presentation, such as vascular dementia and diffuse Lewy body dementia. The chapter also considers the broad array of behavioral consequences which may accompany cognitive dysfunction, including the common presentations of dementias more specifically affecting brain memory mechanisms, such as Alzheimer’s disease, and others which predominantly affect inhibitory and executive functions, such as fronto-temporal dementia and chronic traumatic encephalopathy. Two appendices also accompany the chapter - one describing the specific assessment measures used in federally funded Alzheimer’s research centers, and the other describing resources for clinicians available from the Alzheimer’s Association.