When Walking Outlasts Cognition: Rethinking the Late-Stage of Lewy Body Dementia.

BACKGROUND: Lewy body dementia (LBD) is characterized by pervasive cognitive, motor, and neuropsychiatric symptoms. Although cognitive decline has traditionally shaped staging and prognosis, accumulating evidence indicates that gait and postural disturbances follow partially independent trajectories and may remain preserved even as cognition deteriorates. These observations challenge conventional assumptions about late-stage decline and suggest that locomotor function may complement cognitive measures when assessing late-stage transition in LBD. SUMMARY: This review synthesizes current evidence on gait disturbances across the LBD spectrum and their neural substrates, in comparison with Alzheimer's disease (AD) and Parkinson's disease (PD). Gait impairment in LBD arises from distributed network dysfunction involving dopaminergic and cholinergic pathways, fronto-striatal, parietal, and cerebellar contributions, resulting in greater gait variability, reduced automaticity, and heightened dual-task costs relative to AD and PD. Despite this vulnerability, preserved procedural memory, brainstem locomotor circuits, and cerebellar-cortical compensation may allow walking to persist longer than cognition in some individuals. In advanced disease, rapid gait deterioration has been described near the end of life, suggesting that gait trajectories may capture aspects of late-stage decline that cognitive measures, affected by fluctuations and attentional instability, may not reliably reflect. KEY MESSAGES: -Gait and cognition do not decline in parallel in LBD; in some individuals, walking may outlast cognitive abilities.-Gait disturbances reflect distributed network dysfunction rather than isolated motor system degeneration.-In late stages, gait performance may offer a clinically useful indicator of disease transition when cognitive testing becomes less reliable. -Integrating gait assessment into clinical evaluation may enhance prognostication and support palliative care planning in LBD.