Prevalence of Lewy body pathology and phenotypic associations in patients with mild cognitive impairment: Evidence from the Interceptor study

INTRODUCTION Clinical effects and prevalence of Lewy body (LB) pathology in patients with mild cognitive impairment (MCI) remain poorly understood. METHODS We assessed LB pathology in 339 patients with MCI from the Italian multicenter Interceptor cohort using the cerebrospinal fluid α‐synuclein seed amplification assay. Baseline assessment was followed by serial cognitive evaluations over 3 years. RESULTS LB+ participants ( n = 50, 15%) were older and showed a higher frequency of parkinsonism, falls, and delirium episodes than those LB–, although these differences were not statistically significant. At follow‐up, patients with biomarker evidence of Alzheimer's disease (AD), either isolated (AD+/LB–) or with concomitant LB pathology (AD+/LB+), showed the fastest cognitive decline and progression to dementia. DISCUSSION In a multicenter MCI cohort, LB pathology was associated with older age and an increased frequency of motor/psychiatric symptoms. Larger studies are needed to clarify the independent contribution of AD and LB pathologies to the MCI phenotype and clinical progression.