Alzheimer's disease, commonly known as "Alzheimer's disease", is a type of dementia that accounts for 60% to 80% of all dementia cases. The most well-known symptom of patients is memory loss, which is like having an eraser in the mind, constantly erasing good memories of family, love, and friendship. In addition to this, patients also experience symptoms such as aphasia, decreased visuospatial ability, decreased abstract thinking and calculation, and personality and behavior changes. Recently, a research team from Shandong Second Medical University published a new study in the American Public Library of Science: Synthesis showing that light** can improve sleep and mental and behavioral symptoms in patients with Alzheimer's disease, and to a lesser extent.
Phototherapy improves Alzheimer's symptoms
In our country, there are nearly 10 million people with Alzheimer's disease. The disease is not only a complex health problem, but also causes intractable family and social problems. For the families of patients, they not only suffer from mental blows, but also face a more realistic burden of care. That's why it's so important to find what works.
Patients with Alzheimer's disease often have biological rhythm disorders, such as sleep rhythm disorders, which can further affect the patient's cognitive function, emotional performance, and behavioral changes. Previous studies have found that the supraoptic nucleus and pineal gland of the hypothalamus regulate biological rhythms, and the secretion level of the pineal gland is affected by light. As a result, researchers at home and abroad have gradually carried out research on the efficacy of light** on Alzheimer's disease.
Light** is a non-pharmacological intervention strategy designed to normalize the patient's circadian rhythm through artificial or natural light sources. At present, the application of light at home and abroad is mainly used in Alzheimer's disease, such as light box, LED lamp, daylight, transcranial and transnasal near-infrared light instruments.
In recent years, there has been an increasing number of international studies on the effects of light exposure** in Alzheimer's disease**, especially on the effects of light on patients' biological clock and sleep. Several experimental studies have shown that light** may have a positive effect on improving sleep quality and mental and behavioral symptoms.
In China, the application of light in Alzheimer's disease is relatively new, and research and practice are relatively limited. Previously, a study from Ningbo Kangning Hospital investigated the effect of light exposure** on agitation behavior in patients with Alzheimer's disease, including 61 patients, by fixing a light source with continuously adjustable intensity on a portable cart and turning on the light source from 9 a.m. to 9:30 a.m. every day; The patient faces the light source and the distance between the two is within 50 cm for 4 weeks. Studies have found that light** can significantly reduce the incidence of mental confusion in patients and reduce the burden on caregivers. Its mechanism of action may involve the effects of light on the biological clock and melatonin, among other things.
The research team from Shandong Second Medical University searched multiple research databases and selected and analyzed 15 studies published from 2005 to 2022 in 7 countries, including a total of 598 patients with Alzheimer's disease, and found that light** significantly improved sleep efficiency, improved daytime stability (a measure of circadian rhythm strength), and reduced intraday variability (how often people switch between daytime rest and activity). In people with Alzheimer's disease, light exposure** also reduces depressive symptoms, irritation and caregiver burden.
There are also other ** effects
At present, some medical institutions in China may use non-drugs for patients with Alzheimer's disease**, but light** is not widely used in the clinical practice of this disease**. However, in many other areas, light** has been widely studied and used, especially in relation to biological clocks, sleep, and mental health.
Alleviate mood disorders
Light therapy may relieve some mood disorders, such as seasonal depression. Seasonal depression is a periodic mood disorder caused by brief periods of light exposure in winter, which often occurs in autumn and winter and resolves in spring and summer, and some people who live in high-latitude areas with little sunlight are more susceptible. In the guidelines, phototherapy has been used in clinical practice as a first-line treatment for seasonal depression and can effectively reduce depressive symptoms.
Adjust your biological clock
Phototherapy can be used to adjust the biological clock and promote a normal sleep-wake cycle. This is an effective means of improving sleep for people who need to adjust to jet lag or shift work.
Disease
In the field of diseases, light refers to the use of light waves to irradiate the surface, part of which is absorbed and converted into heat, chemical energy and biological energy, and plays a certain biological and physicochemical role. Phototherapy at a specific wavelength can cause some diseases, and generally the longer the wavelength, the stronger its ability to penetrate. For example, red and blue light can be applied to **acne; Yellow light is suitable for facial allergies, contact dermatitis, etc.; Ultraviolet light such as 308 excimer light is suitable for vitiligo, psoriasis, atopic dermatitis, etc.
In addition, phototherapy can be used for neonatal jaundice, tumors and other diseases**. Some studies have shown that phototherapy may have a positive effect on attention and behavior in people with ADHD; It is also an effective adjunct to bipolar disorder.
Prescribe a "light prescription".
Sunlight is an important source of natural light and one of the most common. On the one hand, sunlight helps the synthesis of vitamin D, which is beneficial to bone health and strengthens the immune system. On the other hand, soaking up the sun while outdoors can improve mood and reduce stress and anxiety. It should be noted that sun exposure should be moderate, timely and appropriate to avoid discomfort or injury. Specifically, refer to the following "sun exposure prescriptions" and consult your doctor or health care professional for advice to make a plan.
First, choose the appropriate time for sun exposure, which can be adjusted according to factors such as sun height, skin color, and geographical location. Be careful to avoid exposure to the sun in the middle of the day when the sun is strong, and try to choose the morning or afternoon when the sun is mild.
Second, control the duration of sun exposure. Prolonged exposure to strong sunlight may cause sunburn and increase the risk of cancer. Typically, 15 to 30 minutes of sunbathing a day is enough to meet most people's vitamin D needs.
Third, do a good job of local sun protection, such as using sunscreen, etc., to protect ** from ultraviolet rays. The sunscreen you choose should have an adequate SPF and be reapplied regularly.
Fourth, pay attention to the sun exposure needs of special groups, such as the elderly, infants, and sensitive people, etc., and need to control the sun exposure time more carefully and take sun protection measures.
In addition to sunlight, people are also exposed to various artificial light sources in their daily lives, including warm lights, fluorescent lights, LED lights, etc. These different types of light sources have different color temperatures, illuminances, blue light, etc., which can also have an impact on the human body. The use of inappropriate light sources will cause problems such as visual fatigue, insomnia, light radiation hazards and biological rhythm disorders.
From a color temperature perspective, yellow light makes people warm, and blue and white light makes people calm. Generally, in low-illumination places or cold climate conditions, warm color temperature should be used, such as guest rooms, bedrooms, wards, etc.; Cold color temperature can be used under high illumination or warm conditions, such as hot processing workshops, etc.; Medium illumination or intermediate color temperature in general, such as offices, classrooms, shopping malls, clinics, etc. It is important to note that the color temperature suitable for reading and writing is between warm and cold light. Because blue and white light provides the greatest brightness contrast compared to pale yellow light, it will inhibit the visual function and cause eye fatigue. From the perspective of blue light, blue light can cause visual fatigue and even damage, and it will also have a certain impact on sleep, and almost all LED lights have blue light. It should be noted that when purchasing, you can choose products with the implementation standard IEC TR 62778 (the latest standard for LED blue light hazard assessment) on the packaging; Excessive exposure to blue light should be avoided at night. In addition, the light from some lamps will flicker at a certain frequency, which is imperceptible to the naked eye, but it can make the eyes very tired, which can cause damage to the human body. When buying lamps, you can turn on the mobile phone camera function to test the lamps, if the mobile phone screen appears grid, it means that the light of the lamps is flickering at a certain frequency, and you should avoid buying.
Meng Qinghui, a professor at Shandong Second Medical University.