Mild cognitive impairment in patients with moderate to severe chronic plaque psoriasis

Background: Psoriasis is frequently associated with cardiometabolic comorbidities and depression that are risk factors for cognitive impairment. Objective: To investigate cognitive performance in psoriatic patients. Method: Cognitive performances were assessed by neuropsychological tests in 41 patients with psoriasis and 37 controls. Diagnostic criteria for mild cognitive impairment (MCI) were (1) subjective complaint of a memory deficit, confirmed by a relative or caregiver, (2) pathological performance on neuropsychological tests investigating cognitive domains, (3) normal performance of daily living activities and (4) no dementia. Neuroimaging was studied by high-field magnetic resonance imaging and cortical thickness analysis. Results: MCI was found in 18 out of 41 (44%) patients with psoriasis compared to 4 out of 37 (11%) controls (p = 0.002). In particular, patients with psoriasis had lower scores in the delayed recall of the Rey Auditory Verbal Learning Test (p = 0.04), Backwards Digit Span Test (p = 0.002), Weigl's Sorting Test (p = 0.01) and Trail Making Test B (p = 0.008). In the 7 patients submitted to cortical thickness analysis, a reduction in brain thickness in parahippocampal, superior temporal and frontal gyri of the left hemisphere was observed. Conclusions: Patients with psoriasis may have a precocious impairment of long-term verbal memory, executive functions and attention.