The benefits of light for people with dementia

Some 50 million people suffer from dementia worldwide, a number that will triple in the coming decades. We are talking, therefore, about one of the most important public health problems that exist today. Early diagnosis, adequate assessment, appropriate treatment and allocation of resources are the key elements to address it in a comprehensive manner.

This treatment of symptoms associated with dementia includes pharmacological and non-pharmacological therapies. In the clinical setting, it is common to resort to medications, but they show modest effectiveness and significant side effects.

For this reason, numerous guides and experts recommend interventions that do not use drugs to combat psychological symptoms (agitation, irritability, sleep disorders, anxiety, etc.) as the first strategy of action. The exception is if they have previously failed, are not viable, or there is a substantial risk of harm to the patient or others. Light therapy is included among these non-pharmacological actions.

Easily applicable on a daily basis
Light therapy consists of exposing the patient to certain levels of light under controlled conditions. It can be administered in different ways, taking advantage of outdoor sunlight or using artificial devices such as specific lamps or ceiling lights.

In any case, that light has to penetrate the eyes to be effective. It is not mandatory to look directly at it, so the user can carry out other activities while receiving stimulation in their visual field, such as watching television, eating or chatting. This makes it an intervention that is easily applicable on a daily basis.

Numerous research provides evidence on the positive short- and long-term consequences of light therapy on the symptoms associated with dementia, especially in relation to mood and behavioral and sleep alterations. But why does it work?

Objective: normalize the circadian rhythm
The light-dark cycle works as an environmental synchronizer of circadian rhythms: sleep-wake, temperature, respiratory and heart rate, etc. As these patterns are controlled by certain brain regions (mainly by the suprachiasmatic nucleus of the hypothalamus), the degenerative changes suffered by people with dementia are the biological basis of circadian alterations. These are associated with cognitive impairment and mood, behavior and sleep disorders.

Therefore, the objective of light therapy is based on increasing light exposure in order to establish an adequate circadian rhythm and partially reverse the symptoms that occur when it goes out of rhythm.

Going into practice
Our research group has carried out a study in a gerontological complex specialized in dementia. Participants received 30-minute light therapy sessions in the morning, five days a week (Monday to Friday) for four weeks.

This treatment was carried out in a room specially set up for the development of the intervention. We used specific lamps whose intensity was adjusted by light measurements with a lux meter.

In each of the sessions, changes in behavior, mood and certain physiological parameters (heart rate and blood oxygen saturation) were recorded – during the therapy, immediately before and immediately after.

The results demonstrate the positive effects of light exposure on the patients' mood, their level of alertness and the aforementioned physiological parameters.

Advantages of light therapy
In conclusion, it is important to highlight how easy it is to implement this intervention in the daily routine of institutions caring for people with dementia, if we consider both economic and logistical aspects.

Likewise, because active interaction is not necessary to obtain benefits from light therapy, it is especially suitable for those in advanced stages of dementia. In your case, other types of treatments are difficult or impossible to carry out.

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Source: The Conversation. Authorship:

Nuria Cibeira González
Research support technician. Neuropsychologist, Universidade da Coruña

Ana Belén Maseda Rodríguez
Hired Professor Doctor (medicine area), Universidade da Coruña

José Carlos Millán Calenti
Professor of Medicine. Gerontology and Geriatrics Profile, Universidade da Coruña

Laura Lorenzo Lopez
Contracted Professor Doctor at the Faculty of Health Sciences, Universidade da Coruña