Alzheimer's disease, memory loss and low level light therapy
A study just published in the JAD (the Journal of Alzheimer's Disease) offers evidence that low level light therapy can help brain metabolism and memory in Alzheimer's disease. The authors note:
"Cerebral hypometabolism characterizes mild cognitive impairment and Alzheimer's disease. Low-level light therapy (LLLT) enhances the metabolic capacity of neurons in culture through photostimulation of cytochrome oxidase, the mitochondrial enzyme that catalyzes oxygen consumption in cellular respiration. Growing evidence supports that neuronal metabolic enhancement by LLLT positively impacts neuronal function in vitro and in vivo. Based on its effects on energy metabolism, it is proposed that LLLT will also affect the cerebral cortex in vivo and modulate higher-order cognitive functions such as memory."
Their intent was to reveal more about how LLLT would improve brain function in living tissue (in vivo):
"We tested the hypothesis that in vivo LLLT facilitates cortical oxygenation and metabolic energy capacity and thereby improves memory retention."
They used a form of memory that is modulated by prefrontal cortex activation, called fear extinction, to test their hypothesis by directly measuring prefrontal cortex oxygen concentration (with fluorescent quenching oximetry and by quantitative cytochrome oxidase histochemistry). In this way they could objectively determine the effects of LLLT on brain metabolism. The results were fascinating and relevant for the treatment of Alzheimer's disease:
"Experiment 1 verified that LLLT increased the rate of oxygen consumption in the prefrontal cortex in vivo. Experiment 2 showed that LLLT-treated rats had an enhanced extinction memory as compared to controls. Experiment 3 showed that LLLT reduced fear renewal and prevented the reemergence of extinguished conditioned fear responses. Experiment 4 showed that LLLT induced hormetic dose-response effects on the metabolic capacity of the prefrontal cortex."
Hormetic means in this context that the character and quality of the response depended on the duration and intensity of LLLT exposure. This adds to the growing body of evidence supporting the use of LLLT for disorders of cognition and mood including Alzheimer's disease, depression and many more. (I use low level light and laser therapy in the Lapis Light clinic). The authors conclude:
"These data suggest that LLLT can enhance cortical metabolic capacity and retention of extinction memories, and implicate LLLT as a novel intervention to improve memory."