Promising new lead in the fight against Alzheimer's disease

Alzheimer's disease is a silent epidemic affecting more and more older people. No treatment has yet been successful in curing this neurodegenerative disease, but some treatments can relieve certain symptoms and improve patients' quality of life. Among these methods, light therapy appears to be showing promising results.

Benefits of light therapy

Phototherapy involves exposing the patient to bright light, similar to daylight, for a specified period of time. This therapy has been used successfully to treat seasonal depression, but recent studies suggest that it may also provide benefits for patients with Alzheimer's disease.

Recent meta-analysis⁽¹⁾ It was revealed that light therapy significantly improves the quality and efficiency of sleep in patients suffering from Alzheimer's disease. In addition, it reduces some common psychological and behavioral symptoms, such as agitation, anxiety, and abnormal motor behaviors.

The effects will be confirmed by larger studies

Although the results are promising, the authors of the meta-analysis stress that the studies analyzed were of limited numbers. They therefore recommend conducting large-scale clinical trials to confirm the observed benefits.

In addition, further research will be needed to determine optimal light therapy settings, such as light intensity, duration of exposure, and time of day. It will also be necessary to evaluate the long-term persistence of effects and examine whether phototherapy poses risks or adverse effects in some patients.

Mechanisms of phototherapy

The mechanisms explaining the positive effects of phototherapy on Alzheimer's disease symptoms are not fully understood. However, several hypotheses have been put forward.

One way is that light makes it possible to resynchronize patients' internal biological clock, which is often disrupted in this neurodegenerative disease. By stabilizing sleep-wake rhythms, light therapy helps improve sleep quality and some associated psychological and behavioral disorders.

Light also promotes the release of some substances involved in regulating mood and emotions, such as serotonin and melatonin. Stimulating these chemical messages would contribute to beneficial effects on behavioral and emotional symptoms.

Finally, some research suggests that phototherapy can directly impact the neurodegenerative mechanisms of the disease, by reducing the buildup of toxic amyloid proteins in the brain and thus temporarily slowing the progression of lesions. This neuroprotective measure requires confirmation.

Integrating phototherapy into comprehensive care

Although additional studies are necessary, phototherapy appears to be a promising treatment modality for Alzheimer's disease, especially for improving some of the painful symptoms in daily life.

Because it has few side effects compared to many drug treatments, this alternative medicine technique can be integrated into non-drug patient care.

In addition to other methods such as adapted physical activity, cognitive stimulation or music therapy, phototherapy has its place in the global care strategy aimed at maintaining the quality of life and well-being of people with Alzheimer's disease.

Light therapy to prevent and treat depression, a risk factor for dementia

In addition to direct effects on Alzheimer's disease symptoms, light therapy also has benefits in preventing this neurodegenerative disease. In fact, depression is a significant risk factor for developing dementia, including Alzheimer's disease, during old age. However, light therapy has been shown to be effective in several studies in relieving symptoms of depression.

Light therapy has been used since the 1980s and is now known as a first-line treatment for seasonal depression. Several meta-analyses⁽²⁾ They confirm that daily exposure to bright light reduces symptoms of depression in many patients who suffer from this type of winter depression. In some cases, light therapy is as effective as antidepressant medications.

But the beneficial applications of this light therapy don't stop at seasonal mood disorders. Recent studies suggest that light therapy can also effectively treat so-called “non-seasonal” depressive episodes that can occur at any time of the year.⁽³⁾.

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