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 dementiaspecialist;
• Patient participant is age 40 and older;
• Patient participant has a diagnosis verified by a dementia specialist within 24 monthsof: subjective cognitive decline (Shaw et al., 2018), or mild cognitive impairment ordementia, according to DSM-IV (DSM-IV-TR, 2000) and/or National Institutes ofAging-Alzheimer's Association (Albert et al., 2011; McKhann et al., 2011) criteria;
• The etiologic cause of cognitive impairment is uncertain after a comprehensiveevaluation by a dementia specialist, including general medical and neurologicalexamination, mental status testing including standard measures of cognitiveimpairment, laboratory testing, and structural neuroimaging;
• Cognitive disorder is considered to be on the Alzheimer's continuum, including, butnot limited to, mild cognitive impairment with suspected Alzheimer's pathology thatdoes not reach the criteria for dementia;
• Dementia specialist deems that CSF Alzheimer's disease biomarkers are appropriate asper routine clinical care;
• Patient participant consents to a lumbar puncture for CSF analysis as part of clinicalcare.

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, maycause significant psychological harm or otherwise negatively impact the patient orfamily;
• Amyloid status already known to patient or dementia specialist based on prior Aβpositron 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 asymptomaticindividuals;
• Aβ and tau CSF biomarkers ordered for non-medical purposes (e.g., legal, employmentscreening, insurance coverage, patient or family member curiosity);
• Current (i.e., active) patient participation in an anti-amyloid or anti-tautherapeutic trial;
• Presence of other significant chronic brain disease in patient (e.g., malignanttumor);
• Patient had symptomatic stroke or transient ischemic attack within the previous 12months;
• 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 participantlacks capacity to do so themselves.