Association between the Indoor Visual Environment and Cognition in Older Adults: A Systematic Review

The visual environment plays a crucial role in how individuals perceive and interact with their surroundings, particularly for older adults, who spend most of their time indoors. Cognitive decline and daily cognitive performance in older adults are significantly influenced by the characteristics of indoor visual environment (IVE). However, there is currently a lack of comprehensive understanding regarding the effects and associations of IVE characteristics on cognitive performance in older adults. Systematic review is a comprehensive, transparent, and structured approach that employs a predefined, rigorous methodology to identify, select, and critically assess all relevant studies, minimizing bias and providing a reliable summary of the evidence. Therefore, the aim of this paper was to comprehensively synthesize the evidence on the association between IVE characteristics and cognition in older adults through a systematic review. A systematic search was conducted using three databases, i.e., Web of Science, PubMed, and EBSCO, along with forward and backward citation tracking, covering studies published from database inception to April 2024. Inclusion criteria were peer-reviewed quantitative or mixed-method studies targeting older adults, with IVE characteristics as the intervention and cognitive function or related assessments as outcome. Only studies published in English were included. The quality of evidence was assessed using the Mixed Methods Appraisal Tool (Version 2018). A total of 10 studies met the inclusion criteria. The results show that the methodological quality of most studies was high, and IVE characteristics have dual effects on cognitive performance in older adults, with different IVE characteristics affecting various aspects of cognitive function. Importantly, older adults with cognitive impairments maintain normal levels of color perception, color or numbers as environmental cues have temporal relevance, and differences in texture direction or range may lead to visual illusions, negatively affecting their cognitive performance. Furthermore, three higher-order dimensions were constructed to explain the mapping associations between them. The cognitive needs of older adults for the IVE were further inferred based on their cognitive performance. This study contributes to a comprehensive understanding of the association between IVE characteristics and cognitive performance of older adults, and provides a strong basis and reference for the const