Light therapy

Changes in the part of the brain controlling sleep-wake cycles can disrupt the sleep patterns of people living with dementia. [1] This can lead to broken nighttime sleeping and increased daytime sleeping. [2] There is a theory that exposing people living with dementia to a source of bright light might stimulate this part of the brain and restore sleep patterns. [3] This may also reduce agitation, especially at twilight (‘sundowning’), [4] and neuropsychiatric symptoms such as depression. [1]

Sources of light tested in research conditions include:

• A light box placed at eye height approximately one metre away from the person living with dementia
• Light visors
• Special mounted light fixtures
•  Increased exposure to natural light
• Simulated changes between dawn and dusk. [1]

This evidence theme on light therapy is a summary of one of the issues identified in a scoping review of dementia research. If you need more information on this topic, try using the PubMed search below.

Reviews on the effectiveness of light therapy have examined its impact on sleep, activities of daily living, depression, and agitation for people living with dementia. All have found conflicting findings. In other words, there is inconclusive evidence that light therapy or changing the overall light level influences:

• Sleep [3, 5]
• People’s ability to manage their self-care activities [1, 3]
• Mood [3]
• Cognitive function [3]
• Responsive behaviours such as agitation, restlessness, and aggression [4, 6, 7]
• Psychiatric symptoms such as depression and psychosis. [1]

In other words, some studies found evidence supporting light therapy while others did not. Similarly, one review found light therapy may even worsen agitation [6] while another did not find any connection between light and agitation. [8]

Reviews raised some concerns about the methods used in studies on this topic which could lower our confidence in the findings. These include:

• The small number of participants [9]
• The wide variety of devices, light intensities, durations, and frequencies tested across studies, which makes it difficult to compare findings [9]
• Differences in the type and severity of dementia experienced by study participants, which may contribute to the variations in findings. [1]

Even without a formal therapy such as bright light therapy, the light available in the home can be reviewed and modified if necessary to help the person living with dementia.

• Relieving areas of dimness may help people see their way better and enhance self-care activities. This might mean opening more windows or encouraging people to go outdoors. [2] 
• Position seating as close to open windows, preferably with a view of a garden.
• Outdoor light in the morning and evening may help stabilise a person’s body clock. 

Bright light therapy requires a moderate investment of time for staff training and supervision and equipment costs. [2] Until the evidence base for this approach becomes more consistent, explore ways to improve levels and types of lighting to assist people living with dementia to make sense of their environment.

• Train staff about lighting so that they know how to monitor it to reduce falls, help people find their way, enhance positive mood, and support activities of daily living. [10]
• Incorporate flexible lighting levels to accommodate individual needs as a part of a person-centred approach to design. [10]
• Bring natural light inside during the day as much as possible to foster a sense of wellbeing. This could be achieved by keeping curtains open, opening windows, installing skylights, or using light pipes or glass blocks. 
• Keep the home as dark as possible during nighttime to help people differentiate between day and night. [11]  
• Read some of the practical guidance (see resources below).

1. Forbes D, Blake CM, Thiessen EJ, Peacock S, Hawranik P. Light therapy for improving cognition, activities of daily living, sleep, challenging behaviour, and psychiatric disturbances in dementia. Cochrane Database Syst Rev. 2014(2):CD003946.
2. Scales K, Zimmerman S, Miller SJ. Evidence-based nonpharmacological practices to address behavioral and psychological symptoms of dementia. Gerontologist. 2018;58:S88-S102.
3. Marquardt G, Bueter K, Motzek T. Impact of the design of the built environment on people with dementia: An evidence-based review. HERD. 2014;8(1):127-57.
4. Cabrera E, Sutcliffe C, Verbeek H, Saks K, Soto-Martin M, Meyer G, et al. Non-pharmacological interventions as a best practice strategy in people with dementia living in nursing homes. A systematic review. Eur. Geriatr. Med. 2015;6(2):134-50.
5. O'Caoimh R, Mannion H, Sezgin D, O'Donovan MR, Liew A, Molloy DW. Non-pharmacological treatments for sleep disturbance in mild cognitive impairment and dementia: A systematic review and meta-analysis. Maturitas. 2019;127:82-94.
6. Livingston G, Kelly L, Lewis-Holmes E, Baio G, Morris S, Patel N, et al. Non-pharmacological interventions for agitation in dementia: Systematic review of randomised controlled trials. BJPsych. 2014;205(6):436-42.
7. Wang G, Albayrak A, van der Cammen TJM. A systematic review of non-pharmacological interventions for BPSD in nursing home residents with dementia: From a perspective of ergonomics. Int. Psychogeriat. 2019;31(8):1137-49.
8. Livingston G, Kelly L, Lewis-Holmes E, Baio G, Morris S, Patel N, et al. A systematic review of the clinical effectiveness and cost-effectiveness of sensory, psychological and behavioural interventions for managing agitation in older adults with dementia. Health Technol. Assess. 2014;18(39):1-226.
9. Abraha I, Rimland JM, Trotta FM, Dell'Aquila G, Cruz-Jentoft A, Petrovic M, et al. Systematic review of systematic reviews of non-pharmacological interventions to treat behavioural disturbances in older patients with dementia. The SENATOR-OnTop series. BMJ Open. 2017;7(3):e012759.
10. Alzheimer's WA. Dementia enabling environments: Lighting [Internet]. Osborne Park, WA: Alzheimer's WA; 2020 [cited 2023 Jun 29]. Available from: https://www.enablingenvironments.com.au/lighting.html
11. Anderiesen H, Scherder EJ, Goossens RH, Sonneveld MH. A systematic review--physical activity in dementia: The influence of the nursing home environment. Appl. Ergon. 2014;45(6):1678-86.