Self-referential network characteristics in patients with subjective cognitive decline accompanied by metacognitive impairment / 中华神经医学杂志

ABSTRACT

Objective:To explore the characteristics of self-referential network (SRN) functional connectivity in subjective cognitive decline (SCD) patients with normal and impaired metacognition.Methods:Seventy-one subjects were selected from Alzheimer's Disease Neuroimaging Initiative (ADNI) database, with 25 cognitively normal controls and 46 SCD patients. The metacognitive level of SCD patients was assessed by Everyday Cognition Scale (ECog), and then, they were divided into a metacognitively normal group ( n=25, metacognitive scores>-0.074) and a metacognitively impaired group ( n=21, metacognitive scores≤-0.074). Results of Geriatric Depression Scale (GDS), Montreal Cognitive Scale (MoCA), Mini‐Mental State Examination (MMSE), Rey Auditory Word Learning Test (RAVLT), Logical Memory Scale, expressions of pathological markers (cerebrospinal fluid β-amyloid protein [Aβ], total tau protein [t-tau] and phosphorylated tau protein [p-tau]), brain glucose metabolism, and functional magnetic resonance imaging (fMRI) were collected and compared among the 3 groups. Independent component analysis (ICA) was used to extract SRN and analyze the different brain regions among the 3 groups; Pearson correlation was used to analyze the correlations of SRN functional connectivity changes with cognitive scales and pathological markers. Results:No significant differences in demographic characteristics (age and gender), scores of GDS, MoCA and MMSE, or levels of Aβ, t-tau, p-tau and brain glucose metabolism were noted among the 3 groups ( P>0.05). The metacognitive scores in metacognitively impaired group were significantly lower than those in metacognitively normal group and cognitively normal controls ( P<0.05). Significant difference in the functional connectivity of bilateral anterior cingulate gyrus and bilateral orbitofrontal cortex was noted among the 3 groups (TFCE-FWE correction, P<0.01, voxel>100); compared with the cognitively normal controls, the metacognitively impaired group showed significantly decreased functional connectivity of bilateral orbitofrontal cortex, while the metacognitively normal group showed enhanced functional connectivity of bilateral orbitofrontal cortex (TFCE-FWE correction, P<0.01, voxel>100); compared with the metacognitively normal group, the metacognitively impaired group had statistically decreased functional connectivity of bilateral orbitofrontal cortex (TFCE-FWE correction, P<0.01, voxel>100). Further correlation analysis showed that difference value of functional connectivity of bilateral orbitofrontal cortex between metacognitively impaired group and cognitively normal controls was negatively correlated with RAVLT-immediate scores ( r=-0.445, P=0.043); difference value of functional connectivity of bilateral orbitofrontal cortex between metacognitively impaired group and metacognitively normal group was negatively correlated with RAVLT-immediate scores ( r=-0.463, P=0.034). Conclusion:SCD patients with different metacognitive levels have characteristic SRN functional connectivity changes; impaired metacognition may be an early feature of Alzheimer's disease.