Study On The Cognitive Dysfunction Of Insomniacs With Contingent Negative Variation And Electroencephalogram Power Spectrum

Objectives:Cognitive dysfunction such as memory,attention,speed of information processing or executive functions has frequently been found in patients with insomnia.The event-related evoked potential studies(ERP)has been applied as an effective electro-technique to study the cortical information processing.And in ERPs studies,the so-called contingent negative variation(CNV)may be the best choice.Additionally,FFT can be used to study cortical excitability,which may be a better choice for exploring higher cognitive functions.In our study,We combined CNV and FFT to study the inhibition and habituation of the cortex,and explored the pathophysiological mechanism of cognitive dysfunction in insomnia patients.Method:30 primary insomnia patients(PI)and 30 normal controls(NC)were included,inclusion criteria or exclusion criteria were performed strickly.We used polysomnography(PSG)to record the sleep and sleep efficiency,arousal index,total sleep time,percentage of each Stage and heart rate have been selected as objective PSG parameters.The CNV was recorded over Cz according to the international 10-20-System.The amplitudes,latencies,areas of different CNV components such as o CNV,i CNV and t CNV,PINV have been selected and analyzed.Behavioral data such as manual reaction time(RT)has been analyzed.Spectral analysis was performed with fast Fourier transformation(FFT)on all channels to make a spectral analyses of EEG datas.Unpaired t-test,variance analysis(ANOVA)with post-hoc analysis,and correlation analysis have been selected statistically.Results:1.There is no difference of age,gender,and BMI between primary insomnia group and normal control group.2.No correlation has been found between different clinical characteristics and different CNV parameters as latency,amplitude,square.3.The primary insomnia group had a little longer reaction times(RT)to S2 compared to the normal control group.4.The A-latency located in Cz or Pz were statistically longer in primary insomnia group than normal control group,the i CNV-latency located in primary insomnia group were statistically shorter than normal control group,the C-latency located in Fz and Cz were statistically shorter in primary insomnia group than normal control group.5.The i CNV-amplitude located in primary insomnia group was lower than normal control group.The o CNV-amplitude or the t CNV-amplitude located in primary insomnia group was higher than normal control group.6.The o CNV-square,t CNV-square,or PINV-square located in primary insomnia group were significant larger than normal control group.7.?1 or ?2 activity distributed in bilateral hemisphere were significantly increased in primary insomnia group than normal control group.There were different distributions in different cortex regions.Additionally,? activity,? activity or ? activity in bilateral hemisphere also has similar results.Conclusions:1.The A-latency located in Cz or Pz were statistically longer in primary insomnia group than normal control group,the i CNV-latency located in primary insomnia group were statistically shorter than normal control group,the C-latency located in Fz and Cz were statistically shorter in primary insomnia group than normal control group.The results showed that compared with normal control group,primary insomnia had longer reaction time,lower alertness,poorer executive function,and less ability to concentrate and maintain.2.The i CNV-amplitude located in primary insomnia group was lower than normal control group.Indicating that the threshold of preactivation was lower and the expectation decreased.The o CNV-amplitude or the t CNV-amplitude located in primary insomnia group was higher than normal control group.suggesting that cortical inhibitory function was delayed or reduced.healthy person had normal levels of sensory cortical preactivation,the peak response was normal,and as the stimulation repeated,cortical functions showed habituation,while primary insomnia was loss of habituation.and cortical inhibition decreased.3.o CNV-square,t CNV-square,or PINV-square located in primary insomnia group were significant larger than normal control group.showing that The regulation of inhibitory function and control ability was decreased in primary insomniacs.4.FFT-? activity distributed in bilateral hemisphere were significantly increased In primary insomnia group than normal control group.suggesting that the high-frequency activity in primary insomnia was more obvious than that in normal control group,and the cortex of primary insomnia was in a state of excessive arousal,Cortical function was active,especially in frontal area.