40 Hz白光经眼无创光疗的光参数对正常人脑波夹带的影响

Effect of Optical Parameters of 40 Hz Transocular Noninvasive Phototherapy on Brainwave Entrainment

目的探索40 Hz白光经眼无创光疗的色温、光源面积、照度三种光参数对诱导正常人脑波夹带响应度的影响。方法选择健康受试者30名,在距离受试者双眼10 cm处进行不同光参数的40 Hz白光刺激,包括(1)不同色温(3500 K、5200 K和7100 K),照度均为400 lux、光源面积均为20 cm×40 cm;(2)不同光源面积(2.5 cm×5 cm、5 cm×10 cm、10 cm×20 cm和20 cm×40 cm),照度均为400 lux、色温均为3500 K;(3)不同照度(100 lux、200 lux和400 lux),色温均为3500 K、光源面积为均20 cm×40 cm,每部分试验纳入受试者10名,对于同一名受试者,每种光参数试验每次刺激时长1 min,重复刺激5次,刺激顺序随机。受试者在接受光刺激的同时实时采集前额极(frontal pole,Fp),包括左额极(Fp1)、额极中点(Fpz)、右额极(Fp2)三处的脑电信号,使用傅里叶变换分析脑电信号数据,将光刺激与静息无光刺激时40 Hz脑电振幅的比值作为衡量该试次脑波夹带响应度的指标,以评估40 Hz经眼无创光疗的不同光参数诱导脑波夹带的响应度。结果(1)色温3500 K的40 Hz白光刺激在三个监测部位诱发的脑波夹带响应度均强于色温5200 K和7100 K(P<0.05),色温5200 K的40 Hz白光刺激诱发的脑波夹带响应度强于色温7100 K,但仅在Fpz处差异具有统计学意义(P<0.05)。(2)光源面积5 cm×10 cm的40 Hz白光刺激诱发的脑波夹带响应度强于光源面积2.5 cm×5 cm(P<0.05),光源面积10 cm×20 cm和20cm×40 cm的40 Hz白光刺激诱发的脑波夹带响应度强于光源面积2.5 cm×5 cm和光源面积5 cm×10 cm(P<0.05),但当光源面积从10 cm×20 cm增加至20 cm×40 cm时,脑波夹带响应度无显著增加(P>0.05);(3)照度400 lux的40 Hz白光刺激诱发的脑波夹带响应度强于照度100 lux(P<0.001)和照度200 lux(P<0.001),照度200 lux的40 Hz白光刺激诱发的脑波夹带响应度强于照度100 lux(P<0.001)。结论在3500~7100 K的色温范围内,40 Hz白光刺激色温越低,脑波夹带响应度越强;照射光源面积的增加可增强脑波夹带响应度,但存在着饱和效应;在100~400 lux照度范围内,脑波夹带响应度与照度呈正相关。

Objective To explore the effects of three light parameters(color temperature,light source area,and illuminance)of 40 Hz white light transocular noninvasive phototherapy on the brainwave entrainment of healthy people.Methods Thirty healthy subjects were selected to receive 40 Hz white light stimulation with different light parameters 10 cm away from eyes as below:(1)different color temperatures:3500 K,5200 K and 7100 K(illuminance:400 lux and light source area:20 cm×40 cm);(2)different light source areas:2.5 cm×5 cm,5 cm×10 cm,10 cm×20 cm and 20 cm×5 cm(illuminance:400 lux and color temperature:3500 K);(3)different illuminances:100 lux,200 lux and 400 lux(color temperature:3500 K and light source area:20 cm×40 cm).The electroencephalogram(EEG)data of left frontal pole(Fp1),middle frontal pole(Fpz)and right frontal pole(Fp2)were collected from 10 subjects in each experiment.Each light parameter was used for 5 repeated stimulations,and each stimulation lasted for 1 min.The sequence of stimuli was random.Fourier transform was used to analyze the EEG data,and the ratio of the amplitude of 40 Hz EEG in light stimulation to the resting light stimulation was used as the index to measure the gamma brainwave entrainment effect so as to evaluate the influence of different light parameters on the gamma brainwave entrainment effect in 40 Hz white light stimulation.Results(1)Brainwave entrainment effect of 40 Hz white light stimulation at 3500 K was stronger than that at 5200 K and 7100 K(P<0.05),and brainwave entrainment effect of 40 Hz white light stimulation at 5200 K was stronger than that at 7100 K.However,there were significant differences only at Fpz(P<0.05).(2)Brainwave entrainment effect of 40 Hz white light with the light source area of 5 cm×10 cm was stronger than that with the light source area of 2.5 cm×5 cm(P<0.05).Brainwave entrainment effect of 40 Hz white light at 10 cm×20 cm and 20 cm×40 cm was stronger than that at 2.5 cm×5 cm and 5 cm×10 cm(P<0.05).However,brainwave entrainment effect was not significantly increased when the light source area increased from 10 cm×20 cm to 20 cm×40 cm(P>0.05).(3)Brainwave entrainment effect of 40 Hz white light stimulation at 400 lux was stronger than that of 100 lux(P<0.001)and 200 lux(P<0.001).Brainwave entrainment effect of 40 Hz white light stimulation at 200 lux was stronger than that of 100 lux(P<0.001).Conclusions In the color temperature range of 3500 K to 7100 K,the lower the color temperature of the 40 Hz white light stimulation,the stronger the brainwave entrainment effect.Increasing the area of the light source can enhance the brainwave entrainment effect,but a saturation effect exists.Brainwave entrainment effect was positively correlated with illuminance in the range of 100 lux to 400 lux.