2.2. Participants

The study was carried out in accordance with the Code of Ethics of the World Medical Association for experiments involving humans (reference no. 17026283) and approved by the Danish Data Protection Agency (RH‐2018‐34). Written informed consent was obtained from all participants. A clinical sample and a control sample were included between February and November 2018. Inclusion criteria for all participants were age ≥65 years and being fluent in Danish. Persons with impaired eyesight or hearing invalidating assessment were excluded. One outpatient memory clinic from each of the five administrative regions of Denmark took part in the data collection. Further inclusion criteria for the clinical sample were: (a) a relevant informant (eg, relative) present at the examination and (b) referred from general practice for diagnostic evaluation. Other referrals (eg, second opinion, genetic counselling) were excluded. Patients were consecutively included at their initial memory clinic admission and administered a preliminary version of BASIC. Patients further underwent an extensive diagnostic work‐up as described in a previous publication.9 A multidisciplinary staff meeting led by senior specialists in neurology, psychiatry or geriatrics blinded to BASIC results subsequently established a consensus diagnosis according to previously described criteria.

The control sample was recruited among participating patients' relatives (mainly spouses) and volunteers from ongoing research projects at the involved memory clinics. Accompanying relatives were informed about the study and asked if they would like to participate as controls. Candidates for inclusion completed a comprehensive questionnaire including medical history and use of medication and alcohol, and candidates with a history of neurological or psychiatric disease or alcohol consumption above recommended national levels were excluded. Remaining candidates were assessed with the MMSE and the 15‐item Geriatric Depression Scale (GDS‐15).22 Further exclusion criteria for the control sample were MMSE <24, and/or GDS‐15 ≥ 6.