A 51-Year-Old Who Lost Her Job Due to Cognitive Decline

Lisa C. Silbert, MD; Deniz Erten-Lyons, MD


April 19, 2021

A clinical diagnosis of Alzheimer disease can be classified as (1) probable Alzheimer disease dementia, (2) possible Alzheimer disease dementia, or (3) probable or possible Alzheimer dementia with evidence of the Alzheimer disease pathophysiologic process.[4] In the context of research, Alzheimer disease is increasingly being replaced with the term "Alzheimer clinical syndrome."[6]

Probable Alzheimer disease dementia is diagnosed when the patient meets criteria for dementia and has the following characteristics:

  • Insidious, gradual onset over months to years

  • Clear-cut history of worsening of cognition by report or observation

  • Initial and most prominent cognitive deficits evident on history and examination in one of the following categories:

    • Amnestic presentation: The most common presentation of Alzheimer disease dementia is early and prominent impairment of learning and recall of recently learned information. Evidence of cognitive dysfunction should also be present in at least one other cognition domain.

    • Nonamnestic presentation: This can include prominent deficits in language, visual-spatial skills, and executive (frontal lobe) dysfunction.

Probable Alzheimer disease should not be diagnosed in the presence of the following:

  • Substantial concomitant cerebrovascular disease, on either history or imaging

  • Core features of dementia with Lewy bodies

  • Prominent features of frontotemporal lobar degeneration

  • Evidence of another concurrent active neurologic disease or nonneurologic medical comorbidity, or use of medication that could have a substantial effect on cognition

Possible Alzheimer disease dementia is diagnosed when the patient has an atypical course (ie, abrupt onset) or an etiologically mixed presentation (ie, features of dementia with Lewy bodies other than the dementia itself).

Probable Alzheimer dementia with evidence of the Alzheimer disease pathophysiologic process requires the presence of a positive biomarker for Alzheimer disease consistent with either CNS amyloid beta deposition (as established by amyloid PET or amyloid beta CSF levels) or neuronal injury (as established by CSF tau levels, 18F-fluorodeoxyglucose PET, or atrophy on structural MRI).

In this case, the patient had biomarker evidence of both CNS amyloid beta deposition (low CSF amyloid beta (1-42) tau index) and neuronal injury (high CSF phospho-tau levels and hippocampal atrophy on MRI), consistent with a diagnosis of probable Alzheimer disease.


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