Subjective cognitive complaints are related to depressive symptoms but not objective impairment in covert cerebral small vessel disease

Abstract

Introduction

Subjective cognitive complaints are common in patients with cerebral small vessel disease (SVD), yet their correspondence to informant evaluations, objective cognitive functions and severity of brain changes are poorly understood. We studied the associations of subjective and informant reports of cognitive difficulties (executive functions and memory) with findings from a comprehensive neuropsychological assessment and brain MRI (white matter hyperintensities, WMH volume) as well as depressive symptoms and functional abilities (instrumental activities of daily living, IADL).

Methods

In the Helsinki SVD Study, 152 older adults with varying degrees of WMH but without stroke or dementia were classified as having normal cognition or mild cognitive impairment (MCI) based on Jak/Bondi neuropsychological criteria. The objective cognitive measures also included continuous domain scores for memory and executive functions. Cognitive complaints were evaluated with the subjective- and informant-versions of Prospective and Retrospective Memory Questionnaire (PRMQ) and Dysexecutive Questionnaire (DEX), functional abilities with the Amsterdam IADL Questionnaire and depressive symptoms with the Geriatric Depression Scale (GDS-15).

Results

Subjective cognitive complaints correlated significantly with informant reports (r=0.40-0.50, p<0.001). After controlling for age, gender and years of education, subjective and informant DEX and PRMQ were not related to MCI or cognitive domain scores (all p-values>0.05). Instead, subjective DEX (OR 1.10, CI 95% 1.05-1.16, p<0.001) and subjective PRMQ (OR 1.06, CI 95% 1.01-1.11, p=0.014) were significantly associated with GDS-15. Informant DEX (standardised β=0.26, p=0.002, f2=0.08) and informant PRMQ (standardised β=0.24, p=0.007, f2=0.06) were significantly related to WMH volume. They were also associated with IADL score (informant DEX, standardised β=-0.33, p=0.001, f2=0.30; informant PRMQ, standardised β=-0.24, p=0.011, f2=0.19).

Discussion

Neither subjective nor informant-reported cognitive complaints were associated with objective cognitive performance in terms of MCI categorisation or more sensitive domain scores of executive functioning or memory. Informant-evaluations were related to functional impairment in IADL and more severe WMH, whereas subjective complaints only associated with depressive symptoms. These findings suggest that awareness of cognitive impairment may be limited in early-stage SVD and highlight the value of informant assessments in the identification of patients with functional impairment.