Increasing Light Exposure for the Prevention of Delirium: A Systematic Review

Delirium is a neurological disorder with correlations to increased hospital length of stays and higher morbidity and mortality rates, particularly in the growing elderly population, making prevention strategies key in improving patient outcomes and health care systems.

Does increased exposure to light, by artificial or natural means, decrease the incidence of delirium?

A systematic review was conducted of 4 revered databases, CINAHL, PubMed, PsycINFO, and Scopus, for articles related to key words "delirium" and "lighting" or "daylight" or "natural light" or "bright light" or "sunlight." Results were narrowed to adult inpatients, defined as age older than 18 years. After limiting for quality of the study and content that addressed the objective, 7 articles were selected for review: 4 related to artificial means of light therapy and 3 consistent with increased exposure to natural light.

Two studies examined the effects of bright light therapy and reported a decreased incidence of delirium. Two studies researched whether increased lighting via a lighting system with varying degrees of intensity throughout the day would prevent delirium, and neither reported a decrease in delirium. The remaining 3 studies focused on whether increased natural light via windows decreased the occurrence of delirium and uncovered no correlation.

It is recommended that the study by Potharajaroen et al, which demonstrated significant findings for bright light therapy preventing delirium, be replicated as well as new pilot studies to enrich the growing body of research. Bright light therapy is a low-cost and easy-to-institute intervention that should be utilized on a case-to-case basis.