Affiliations: [a] Alzheimer’s Disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clinic, Barcelona, Spain | [b] Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain | [c] Memory Unit, Neurology Service, Hospital Santa Creu i Sant Pau, Barcelona, Spain
Correspondence:
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Correspondence to:Lorena Rami, PhD, Alzheimer’s Disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain. Tel.: +34 932275785; Fax: +34 932275783; E-mail: lrami@clinic.ub.es
Note: [1] Both authors contributed equally.
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.
Keywords: Amyloid-β, preclinical Alzheimer’s disease, subjective cognitive decline, tau proteins
