Investigating the Impact of Alzheimer's Disease Diagnostics in British Columbia

Inclusion Criteria: * Participant is either a dementia specialist, or a patient of a consenting dementia specialist; * Patient participant is age 40 and older; * Patient participant has a diagnosis verified by a dementia specialist within 24 months of: subjective cognitive decline (Shaw et al., 2018), or mild cognitive impairment or dementia, according to DSM-IV (DSM-IV-TR, 2000) and/or National Institutes of Aging-Alzheimer's Association (Albert et al., 2011; McKhann et al., 2011) criteria; * The etiologic cause of cognitive impairment is uncertain after a comprehensive evaluation by a dementia specialist, including general medical and neurological examination, mental status testing including standard measures of cognitive impairment, laboratory testing, and structural neuroimaging; * Cognitive disorder is considered to be on the Alzheimer's continuum, including, but not limited to, mild cognitive impairment with suspected Alzheimer's pathology that does not reach the criteria for dementia; * Dementia specialist deems that CSF Alzheimer's disease biomarkers are appropriate as per routine clinical care; * Patient participant consents to a lumbar puncture for CSF analysis as part of clinical care. Exclusion Criteria: * Patient participant has normal cognition; * Patient participant lumbar puncture requires imaging guidance; * Knowledge of amyloid status, in the opinion of the treating dementia specialist, may cause significant psychological harm or otherwise negatively impact the patient or family; * Amyloid status already known to patient or dementia specialist based on prior Aβ positron emission tomography (PET) imaging or previous CSF analysis; * Aβ and tau CSF biomarkers ordered solely based on a family history of dementia, presence of apolipoprotein E4 genotype, or as a screening test for asymptomatic individuals; * Aβ and tau CSF biomarkers ordered for non-medical purposes (e.g., legal, employment screening, insurance coverage, patient or family member curiosity); * Current (i.e., active) patient participation in an anti-amyloid or anti-tau therapeutic trial; * Presence of other significant chronic brain disease in patient (e.g., malignant tumor); * Patient had symptomatic stroke or transient ischemic attack within the previous 12 months; * Life expectancy of patient is less than 24 months based on medical co-morbidities; * Lack of caregiver who can provide corroborative information if the patient participant lacks capacity to do so themselves.