Validation of the neuropathological criteria of the fourth Consortium on dementia with Lewy Bodies in autopsy cases from psychiatric hospitals.

Aim: The pathological criteria from the fourth Consortium on Dementia With Lewy bodies (DLB) in psychiatric cohorts has not been validated. Also, the pathological differences in prodromal DLB subtypes remain unclear. This study aimed to elucidate the clinicopathological features of patients with DLB in psychiatric hospitals.

Methods: Of 165 autopsied cases, patients who developed psychiatric symptoms at 50 years or older were investigated based on the current criteria of DLB. Clinicopathological findings were compared among prodromal DLB subtypes.

Results: Sixteen of 30 cases with DLB pathology had no parkinsonism, which represented diverse nigral neurodegeneration. Regarding the scheme to estimate the likelihood of DLB syndrome, the prevalence of core clinical features excluding rapid eye movement sleep behavior disorder and probable DLB diagnosis were significantly higher in the high-likelihood group than in the low-likelihood group. Regarding the prodromal DLB subtypes, mild cognitive impairment (MCI) onset was identified in 60%, psychiatric onset in 20%, delirium onset in 10%, and motor onset in 10% of cases, and the proportion of psychiatric onset or delirium onset was significantly higher compared with those without DLB pathology. Coexistence of MCI and psychiatric symptoms was observed in 41.6% of the MCI-onset cases. Patients with psychiatric-onset cases were significantly younger at the onset, with a longer disease duration than those with MCI-onset cases. No differences were observed in other clinicopathological variables among the subtypes.

Conclusion: The fourth Consortium pathological criteria for DLB were applicable in a psychiatric cohort. MCI-onset cases in conjunction with core clinical features is the main prodromal DLB subtype, and four cases exhibited isolated psychiatric symptoms for long-term duration.