Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy.
J Alzheimers Dis. 2020;77(1):113-125. doi: 10.3233/JAD-200478.
A system of photosensitive retinal ganglion cells provides 'non-visual' information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the 'master clock', synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer's disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light.
The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep disorders and sleep-wake patterns in AD.
A literature search was conducted, taking into consideration the relevant studies over the last 20 years. Fifteen studies have been thorough: seven followed an environmental-architectural approach and eight followed a treatment devices approach.
Studies agree in considering BLT as a promising non-pharmacological intervention to compensate for circadian rhythm alterations and they support the need for standardized protocols that allow a comparison between multicenter studies.
Interestingly, in an attempt to contain the spread of the COVID-19 pandemic, health authorities have forced the population to stay home. Therefore, AD people are not currently able to enjoy exposure to sunlight. It is predictable that they may experience an exacerbation of circadian disturbances and that the BLT can be an effective response to prevent such exacerbation.
感光视网膜神经节细胞系统为视交叉上核（SCN）提供有关光的昼夜节律序列的“非视觉”信息，视交叉上核作为“主时钟”，使所有生物钟的chronobiological 机制同步。SCN 结构的损伤会改变昼夜节律行为和激素节律，并干扰规律的睡眠-觉醒模式。几项研究表明，在衰老和阿尔茨海默病（AD）中，昼夜节律与环境的同步性发生变化，行为与光失去同步。
目前的综述旨在检查表明强光治疗（BLT）对 AD 睡眠障碍和睡眠-觉醒模式影响的研究。
进行了文献检索，考虑了过去 20 年的相关研究。有 15 项研究进行了深入探讨：7 项采用环境-建筑方法，8 项采用治疗设备方法。
研究一致认为 BLT 是一种有前途的非药物干预措施，可以补偿昼夜节律的改变，并支持需要标准化协议，以便在多中心研究之间进行比较。
有趣的是，为了控制 COVID-19 大流行的传播，卫生当局迫使人们待在家中。因此，AD 患者目前无法享受阳光照射。可以预见的是，他们可能会经历昼夜节律紊乱的加剧，而 BLT 可以有效地防止这种加剧。
