Abstract
Background: Self-reported and informant-reported subjective cognitive
decline (SCD) may be useful in the detection of preclinical Alzheimer’s disease (Pre-AD)
and cognitive impairment related to abnormal amyloid-β (Aβ 42) levels.
Objectives: a) To compare the Subjective Cognitive Decline Questionnaire
(SCD-Q) ratings between Pre-AD subjects and cognitively healthy controls, b) to study the
association of SCD-Q scores with levels of AD biomarkers in cognitively healthy and
cognitively impaired subjects, and c) to compare SCD-Q ratings in cognitively impaired
subjects with or without abnormal Aβ 42.
Methods: Two hundred and seventeen participants (111 subjects; 106
informants) answered the SCD-Q. All subjects underwent a lumbar puncture to determine
levels of Aβ 42 and tau, and an extensive neuropsychological battery. Healthy
subjects were classified as Controls (CTR) or Pre-AD according to the absence or the
presence of abnormal Aβ 42, and those with cognitive impairment (CI) into
Non-amyloid (NonAB-CI) or Amyloid (AB-CI) impairment.
Results: Informants’ SCD-Q scores were significantly higher in the Pre-AD
group than in the CTR group (F = 6.75; p = 0.01). No significant
differences were found in self-ratings. In the cognitively impaired groups, there were no
significant differences in the SCD-Q ratings. In the whole sample, informants’ ratings of
SCD-Q correlated with Aβ 42 (r = –0.21;
p = 0.02) and tau levels (r = 0.28;
p = 0.00).
Conclusions: Higher informants’ ratings of SCD-Q differentiated Pre-AD
subjects from CTR. Informants’ ratings of SCD-Q correlated weakly with cerebrospinal fluid
AD biomarkers.
