Copyright © 2019 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:. Primary objective. To assess the effects of various built environment interventions, in the form of hospital planning and design approaches and features, on the health and wellbeing of older inpatients with cognitive impairment including dementia and delirium. Secondary objectives. To assess the effects of built environment interventions on accompanying persons. These interventions consist of any design feature that supports an accompanying person as they assist or accompany the patient in the hospital. To assess the effects of built environment interventions on staff within inpatient wards who are providing care to older patients with cognitive impairment. To identify gaps in the evidence and outline topics for future research.