title: Subjective cognitive complaints contribute to misdiagnosis of mild cognitive impairment.
abstract: Subjective cognitive complaints are a criterion for the diagnosis of mild cognitive impairment (MCI), despite their uncertain relationship to objective memory performance in MCI. We aimed to examine self-reported cognitive complaints in subgroups of the Alzheimer's Disease Neuroimaging Initiative (ADNI) MCI cohort to determine whether they are a valuable inclusion in the diagnosis of MCI or, alternatively, if they contribute to misdiagnosis. Subgroups of MCI were derived using cluster analysis of baseline neuropsychological test data from 448 ADNI MCI participants. Cognitive complaints were assessed via the Everyday Cognition (ECog) questionnaire, and discrepancy scores were calculated between self- and informant-report. Cluster analysis revealed Amnestic and Mixed cognitive phenotypes as well as a third Cluster-Derived Normal subgroup (41.3%), whose neuropsychological and cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarker profiles did not differ from a "robust" normal control group. This cognitively intact phenotype of MCI participants overestimated their cognitive problems relative to their informant, whereas Amnestic MCI participants with objective memory impairment underestimated their cognitive problems. Underestimation of cognitive problems was associated with positive CSF AD biomarkers and progression to dementia. Overall, there was no relationship between self-reported cognitive complaints and objective cognitive functioning, but significant correlations were observed with depressive symptoms. The inclusion of self-reported complaints in MCI diagnostic criteria may cloud rather than clarify diagnosis and result in high rates of misclassification of MCI. Discrepancies between self- and informant-report demonstrate that overestimation of cognitive problems is characteristic of normal aging while underestimation may reflect greater risk for cognitive decline.
authors.affiliation: 1Department of Psychiatry,University of California San Diego,School of Medicine,La Jolla,California.
authors.forename: Emily C
authors.initials: EC
authors.lastname: Edmonds
authors.affiliation: 1Department of Psychiatry,University of California San Diego,School of Medicine,La Jolla,California.
authors.forename: Lisa
authors.initials: L
authors.lastname: Delano-Wood
authors.affiliation: 1Department of Psychiatry,University of California San Diego,School of Medicine,La Jolla,California.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Galasko
authors.affiliation: 3Department of Neurosciences,University of California San Diego,School of Medicine,La Jolla,California.
authors.forename: David P
authors.initials: DP
authors.lastname: Salmon
authors.affiliation: 1Department of Psychiatry,University of California San Diego,School of Medicine,La Jolla,California.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Bondi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D000704:Analysis of Variance; D001288:Attention; D060825:Cognitive Dysfunction / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000523:psychology*; D003951:Diagnostic Errors; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D057566:Self Report; D011795:Surveys and Questionnaires; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins