The Swedish BioFINDER 2 Study

COHORT A: Cognitively healthy younger individuals (40-65 years of age) INCLUSION CRITERIA * Age 40-65 years * Absence of cognitive symptoms as assessed by a physician with special interest in cognitive disorders. * MMSE score 27-30 at screening visit. * Do not fulfill the criteria for MCI or any dementia according to DSM-V. * Speaks and understands Swedish to the extent that an interpreter is not necessary for the patient to fully understand the study information and cognitive tests. EXCLUSION CRITERIA * Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. * Current significant alcohol or substance misuse. * Significant neurological or psychiatric illness. * Refusing lumbar puncture, MRI or PET. COHORT B: Cognitively healthy elderly individuals (66-100 years of age) INCLUSION CRITERIA * Age 66-100 years * Absence of cognitive symptoms as assessed by a physician with special interest in cognitive disorders. * MMSE score 26-30 at screening visit. * Do not fulfill the criteria for MCI or any dementia according to DSM-V. * Speaks and understands Swedish to the extent that an interpreter is not necessary for the patient to fully understand the study information and cognitive tests. EXCLUSION CRITERIA * Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. * Current significant alcohol or substance misuse. * Significant neurological or psychiatric illness. * Refusing lumbar puncture, MRI or PET. COHORT C: Subjective cognitive decline and mild cognitive impairment INCLUSION CRITERIA * Age 40-100 years. * Referred to the memory clinics due to cognitive symptoms experienced by the patient and/or informant. These symptoms do not have to be memory complaints, but could also be executive, visuospatial, language, praxis, psychomotor or social cognitive complaints. * MMSE score of 24 - 30 points. * Do not fulfill the criteria for any dementia (major neurocognitive disorder) according to DSM-V. * The medical doctor (after clinical assessments, cognitive testing, CSF analyses and structural brain imaging) believes the cognitive complaints are caused by an incipient neurocognitive disorder of any sort. This is defined as any case fulfilling the criteria above (i.e. both SCD and MCI) with an abnormal CSF Aβ42/40 ratio, which is strongly associated with brain Aβ pathology and prodromal Alzheimer's disease. Further, cases with MCI (=minor neurocognitive impairment) due to either Parkinson's disease, Lewy body disease, vascular neurocognitive disorder or frontotemporal dementia (please see Appendix below for clinical criteria and references) can also be included. * Speaks and understands Swedish to the extent that an interpreter is not necessary for the patient to fully understand the study information and cognitive tests. EXCLUSION CRITERIA * Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. * Current significant alcohol or substance misuse. * Refusing lumbar puncture, MRI or PET. COHORT D: Dementia due to Alzheimer's disease INCLUSION CRITERIA * Age 40-100 years. * Referred to the memory clinics due to cognitive symptoms experienced by the patient and/or informant. These symptoms do not have to be memory complaints, but could also be executive, visuospatial, language, praxis or psychomotor complaints. * MMSE score of 12-26 points. * Fulfill the criteria for dementia (major neurocognitive disorder) due to Alzheimer's disease (DSM-V). * Speaks and understands Swedish to the extent that an interpreter was not necessary for the patient to fully understand the study information and cognitive tests. EXCLUSION CRITERIA * Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. * Current significant alcohol or substance misuse. * Refusing lumbar puncture, MRI or PET. COHORT E: Other dementias INCLUSION CRITERIA * Age 40-100 years. * Fulfill the criteria for dementia (major neurocognitive disorder) due to FTD, PDD, DLB or subcortical VaD alternatively the criteria for PD, PSP, MSA, CBS or ALS. * Speaks and understands Swedish to the extent that an interpreter was not necessary for the patient to fully understand the study information and cognitive tests. EXCLUSION CRITERIA * Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. * Current significant alcohol or substance misuse. * Refusing lumbar puncture, MRI or PET.