Abstract
BACKGROUND: Very late-onset schizophrenia-like psychosis (VLOSLP) is a subtype of schizophrenia spectrum disorders in which individuals experience psychotic symptoms for the first time after the age of 60. The incidence of VLOSLP shows a linear relationship with increasing age. However, no studies have reported alterations in spontaneous brain activity among VLOSLP patients and their correlation with cognitive function and clinical symptoms. AIM: To explore VLOSLP brain activity and correlations with cognitive function and clinical symptoms using resting-state functional magnetic resonance imaging. METHODS: This study included 33 VLOSLP patients and 34 healthy controls. The cognitive assessment utilized the Mini Mental State Examination, Montreal Cognitive Assessment, and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Clinical characteristic acquisition was performed via the Positive and Negative Syndrome Scale (PANSS). All participants were scanned via resting-state functional magnetic resonance imaging, and the data were processed using amplitude of low-frequency fluctuations (ALFF), fractional ALFF (fALFF), regional homogeneity, and voxel-mirrored homotopic connectivity (VMHC). RESULTS: The VLOSLP group presented decreased ALFF values in the left cuneus, right precuneus, right precentral gyrus, and left paracentral lobule; increased fALFF values in the left caudate nucleus; decreased fALFF values in the right calcarine fissure and surrounding cortex (CAL) and right precuneus; increased regional homogeneity values in the right putamen; and decreased VMHC values in the bilateral CAL, bilateral superior temporal gyrus, and bilateral cuneus. In the VLOSLP group, ALFF values in the right precuneus were negatively correlated with Mini Mental State Examination score and PANSS positive subscale score, and VMHC values in the bilateral CAL were negatively correlated with the RBANS total score, RBANS delayed memory score, and PANSS positive subscale score. CONCLUSION: The changes of brain activity in VLOSLP are concentrated in the right precuneus and bilateral CAL regions, which may be associated with cognitive impairment and clinically positive symptoms.