German Validation Study of the Subjective Cognitive Decline Questionnaire (SCD-Q)

German Validation Study of the Subjective Cognitive Decline Questionnaire (SCD-Q) and Its Potential Use in Large Cohorts

The SCD-Q (Subjective Cognitive Decline-Questionnaire) is an established instrument to quantify self-perceived cognitive decline. Both self- and informant-rated versions of the SCD-Q are available. However, the SCD-Q has not been validated in the German language yet. Hence, the investigators aim to validate the self-reported SCD-Q in a clinical sample in Germany.

The SCD-Q is a well-established screening instrument to quantify perceived subjective cognitive decline. In addition to self-perceived cognitive complaints, a 24-item questionnaire for informants is part of the SCD-Q. It demonstrates high sensitivity and lower specificity for detecting dementia and early cognitive changes associated with dementia. However, the questionnaire has not been translated into German or validated. Plasma biomarkers for amyloid and tau pathology, as well as for neurodegeneration and astrocytic activation, have been developed and show promising sensitivity and specificity for detecting Alzheimer's disease (AD). A relevant proportion of biomarker-positive patients does not convert to mild cognitive impairment or Alzheimer's disease dementia during the disease course. Currently, the predictive value of blood biomarkers remains to be clarified, particularly in conjunction with SCD. This study aims to validate the SCD-Q in German and analyze possible connections with biomarkers and (digital) cognitive tests. Follow-up visits are planned.

Inclusion Criteria:

• Medical appointment for dementia diagnostics at the Alzheimer Therapie- und Forschungszentrum
• Provision of signed, written and dated informed consent
• Capacity to give informed consent

Exclusion Criteria:

• dementia in a very advance stage
• Illiteracy