Major or Mild Neurocognitive Disorder Due to Alzheimer Disease

Major or mild neurocognitive disorder (NCD) due to Alzheimer disease is an acquired cognitive decline with an insidious onset and gradual progression. Major and mild NCDs exist on a spectrum of cognitive and functional impairment. A decline in one or more cognitive domains, along with a concern about cognition on the part of the patient, a knowledgeable informant, or the clinician, and performance on an objective assessment that falls below the expected level or that has been observed to decline over time represent core features of major or mild NCD. The cognitive impairment is commonly accompanied, and occasionally preceded, by other neuropsychiatric symptoms, described as deterioration in emotional control, social behavior, or motivation, which are described elsewhere. This chapter reviews the diagnostic guidelines, typical and atypical clinical presentations, differential diagnosis, and treatment considerations in Alzheimer-related NCD.