Cognitive Decline

Forgetfulness is a symptom, not a diagnosis. The same complaint may reflect delirium, medication toxicity, depression, sleep-disordered breathing, mild cognitive impairment (MCI), dementia, or more than one brain disease at the same time. A daughter reports that her previously independent father now misses bills and gets lost driving to a familiar store. That history carries more diagnostic weight than a single normal conversation in the examination room. The clinician must determine whether cognition is acutely altered, whether it interferes with independence, and which disease process best explains the pattern. The final formulation has three parts: functional status (normal cognition, MCI, or dementia), the cognitive-behavioral syndrome, and the likely underlying brain disease or contributing conditions. This structure prevents two common errors: labeling every memory complaint as Alzheimer disease and dismissing meaningful decline as normal aging. [1,3]