The Effect Of Right Median Nerve Electrical Stimulation On The Brain Electrical Activity Of Coma Patients After Traumatic Brain Injury

Objective: Coma is the severe consequence of traumatic brain injury(TBI).It is a global public health problem,which imposes a great burden on the society and economy.However,current methods for monitoring the brain function of comatose patients and treating unconsciousness after TBI are limited.With its convenience,low cost and noninvasiveness,right median nerve stimulation(RMNS)is receiving increasing attention from researchers and clinicians.More and more studies have confirmed that RMNS can improve the level of consciousness of comatose patients after TBI.Nevertheless,the underlying machenism is far from being fully elucidated.The purpose of this study is to:(1)analyse the characteristics of encephalography(EEG)of comatose patients after TBI and investigate the prognostic value of EEGs;(2)investigate the mechanism of RMNS for coma-awakening by observing the brain electrical activity of traumatic coma patients before and after receiving RNMS therapy using quantitative methods.Methods: seventy nine coma patients following traumatic brain injury were included in this study?EEGs(electroencephalogram)were acquired pre-stimulation and 1 day,3 days,7 days and 14 days after right median nerve electrical stimulation.(1)EEGs were analyzed on the basis of original EEGs and aEEG;(2)Power spectrum was calculated based on fast Fourier transformation,the power spectrum was divided into 4 bandwidths by frequency: ?(1.0~4.0 Hz)??(4.1~8.0 Hz)??(8.1~13.0 Hz)??(13.1~35.0 Hz).Results:(1)EEG showed diffuse slow waves(?and?),especially ? waves in most traumatic coma patients before right median nerve stimulation,some patients showed burst-suppression and low voltage in EEG,some patients demonstrated non-convulsive seizures;(2)aEEG is correlated with the outcome of comatose patients after TBI,continuous normal voltage is an indicator for better outcome than other types of aEEG;(3)Patients demonstrated a notably decrease in the power of slow waves while increase in the power of fast waves(?and?)after right median nerve electrical stimulation.The left parietal-occipital lobes displayed the most significant change,other regions of the brain showed the same trend while after a longer period of the treatment.Conclusions:(1)most traumatic coma patients showed diffuse slow waves(?and ?)especially ? waves brain electrical activity,some patients showed burst-suppression and low voltage in EEG,some patients showed non-convulsive seizures;(2)aEEG is correlated with the outcome of comatose patients after TBI,continuous normal voltage is an indicator for better outcome than other types of aEEG;(3)Right median nerve electrical stimulation transformed the brain electrical activity of coma patients from slow waves to fast waves,which provides further evidence for coma-awakening of RMNS.