Clinical features of Lewy body dementia: insights into diagnosis and pathophysiology

The recent revision of the consensus diagnostic criteria for dementia with Lewy bodies (DLB) incorporates an expansive set of core and supportive clinical features. However, the relationship between all features and optimal methods for their assessment has yet to be assessed within a single cohort. This has the potential to yield novel pathological insights and streamline diagnostic algorithms.

Twenty-seven prospectively recruited probable DLB patients and 25 age-matched controls were assessed and core and supportive features scored using a unique combination of established clinical and research instruments. Prevalence of all features was reported and diagnostic methods were evaluated. An exploratory factor analysis was performed to uncover latent associations.

Six independent factors were identified accounting for 81% of the diagnostic variance across all core and supportive clinical features. Within these factors, pathologically plausible relationships were highlighted between hallucinations, cognitive fluctuations, and excessive daytime somnolence; between REM sleep behaviour disorder (RBD) and postural hypotension as well as between Parkinsonism and urinary disturbance. 'Prodromal' DLB symptoms were represented in the remaining three factors. The UPDRS and RBD screening questionnaire were evaluated for their suitability for detecting DLB core features and a novel DLB-Parkinsonism scale is proposed to help standardize diagnosis (AUC = 0.94; 95% CI 0.81-1.00).

Clusters of specific core and supportive DLB features are identified, which together with the evaluated screening instruments evaluated, may inform improved strategies to diagnose DLB in clinical and research settings.