Official start of research into the impact of light in the treatment of dementia patients

April 19, 2012

Liège (Belgium) – In conjunction with the University of Liège and Royal Philips Electronics (NYSE: PHG, AEX: PHI), the ISoSL (Intercommunale de Soins Spécialisés de Liège) is launching a project that is unique in the world: research into the effect of variations in lighting level in the living environment, as part of treatment for dementia patients.

The research consists of two parts: one part focuses on the patients, the other evaluates the impact on the medical personnel. The initial results are expected to be available at the end of 2012.

Dedicated leading-edge technology

Dementia is a progressive condition for which there is currently no cure¹. Exclusively medicative treatments only have a limited effect, and the scientific community is unanimously calling for alternative care strategies to be developed that focus on the patient's quality of life, amongst other things by improving their living environment. The research being carried out by the Cliniques de soins spécialisés Valdor-Pèrî ('Valdor-Pèrî clinic for specialist care') and the University of Liège ties in with this.

The issue is so complex that a specialist approach had to be adopted. Advanced lighting technology had to be used which could also be customized: a double requirement which Philips Lighting was able to fulfill by supplying a solution for ‘controlled and modulated light’. The technology, which was developed especially for the research in the Le Pèrî hospital, comprises three systems which correspond to three zones in the psychogeriatric department. These three systems were programmed by the research team to suit the requirements of the research.

From daylight cycle to circadian rhythm
The main lighting system has been installed in the rooms, the corridors and the communal areas. At specific times of the day, which have been set by the research team, the light intensity in the corridor can be as much as 1500 lux, whereas a standard lighting installation in a hospital produces, on average, 350 lux.

In order to analyze the potential healing effect of daylight on the patients' circadian rhythm, Philips Lighting had to integrate various elements into its lighting system. The HealWell lighting concept from Philips (which produces light that varies gradually over the course of the day) was supplemented with various aspects that affect the light intensity, such as the wattage of the fixtures, the tone of light, the arrangement and the orientation of the fixtures. Lastly, the quantity of light was programmed in accordance with the time of day in order to reflect the natural cycle and to take into account the main points in a patient's day in hospital (waking, meal times, therapeutic activities…).

The variations in light intensity are shown in the graph below by means of two curves:

  • in purple, the curve applied in the rooms for the patients,
  • in blue, the curve applied in the rooms for the personnel².



One of the aspects that make this research original therefore lies in the application. In most research the light is applied by means of specific light therapy systems (e.g. light boxes or luminettes). In this research the patients are exposed to light in a more overall and more environmentally friendly way, thanks to a general installation in the various rooms in the psycho-geriatric department. The time available to collect the data, the potential number of patients to be integrated and the support of a university biostatistics laboratory for the processing of the data are all additional benefits which give this research a very scientific basis.

‘School Vision’ in the hospital
The second lighting system proposed by Philips was installed in two specific areas: the multifunctional hall where various activities are organized for the patients, and the medical office where appointments with the doctor are held and certain neuro-psychological tests are carried out. This is the ‘School Vision’ concept, in which one of four lighting scenarios (neutral, energy, focus and calm) can be selected, depending on which one is most appropriate for the relevant activity.

As the name suggests, ‘School Vision’ has already been tested in a number of schools, and special attention will be devoted to it here because the target group of dementia patients is totally different.

Approach with color
The third solution from Philips for this research is the ambient lighting in the bathroom. The special feature of this solution is the dynamic RGB light quality, based on the three primary colors (red, green, blue). These three colors can be mixed to produce other colors.


This modular lighting will be combined with other elements, such as the distribution of essential oils used in aromatherapy and ambience music. These elements will all form the basis for a multi-sensorial relaxation approach based on the Snoezelen (sensory therapy) principles, with which the specialists in the mental health sector are familiar.


Results available from end 2012 onwards
A large amount of data will be gathered during the research. This data will be obtained from the clinical observations made by the members of the multi-disciplinary team on the basis of observation charts and inventories of behavioral elements, and will be linked to the usual objective data, such as blood and urinary analyses. Another original feature of this research is that during the data collection process the research team will also use actimetric techniques to record the patients' physical activity. Lastly, the data will be recorded in real time using a web application which has been custom-made specifically for this purpose by the University of Liège.

The methodology is therefore especially refined; it distinguishes this research from previous studies and makes the project unique in the world. The initial results are expected to be available by the end of 2012.

Rafael Cue Alvarez (Philips Lighting Solutions) is delighted to be working together with the Le Pèrî hospital: “The project ties in perfectly with the strategy of Philips Lighting, which is to deliver solutions tailored to suit an especially wide range of needs in the field of well-being. In this case it involves an application in a hospital environment, but we have also developed innovative projects in schools, retail outlets, and many other places. This underscores yet again Philips' complete mastery of integrated state-of-the-art technologies.”


¹ Further information about this disease is given in the factsheet attached.
² The curve that was worked out for the care personnel is geared as much as possible to that of the patients for the period from when they wake until when they go to sleep, and then differs considerably at the time when night rest commences, so that these personnel with special working hours can also benefit from dynamic light.

For further information contact:

Alain Dejace
Cliniques de soins spécialisés Valdor – Pèrî
('Valdor – Pèrî clinic for specialist care')
Tel. : +32 478 235 567
E-mail :


Philips Corporate Communications
Sarah Facxin
Tel.: +32 2 525 80 78
E-mail :


About Royal Philips Electronics

Royal Philips Electronics of the Netherlands (NYSE: PHG, AEX: PHI) is a diversified health and well-being company, focused on improving people’s lives through meaningful innovation. As a world leader in healthcare, lifestyle and lighting, Philips integrates technologies and design into people-centric solutions, based on fundamental customer insights and the brand promise of “sense and simplicity”. Headquartered in the Netherlands, Philips employs approximately 122,000 employees with sales and services in more than 100 countries worldwide. With sales of EUR 22.6 billion in 2011, the company is a market leader in cardiac care, acute care and home healthcare, energy efficient lighting solutions and new lighting applications, as well as lifestyle products for personal well-being and pleasure with strong leadership positions in male shaving and grooming, portable entertainment and oral healthcare. News from Philips is located at