To study the effects of different frequencies of spinal cord stimulation (SCS) on cortical electroencephalogram in patients with chronic disorders of consciousness (DOC), and establish a SCS stimulation paradigm based on quantitative evaluation.

Twenty-four patients with chronic DOC who underwent SCS in the Department of Neurosurgery, the Seventh Medical Center, Chinese PLA General Hospital were treated with different frequency programmed parameters to record pre- and post-stimulation electroencephalogram. Spectrum analysis was used to extract the energy of different electroencephalogram bands in the frontal lobe region, and to compare their characteristics under different stimulation conditions. Correlation analysis was made between changes in brain electrical spectrum and baseline consciousness level [divided into 2 groups, minimally consciousness state (MCS) and vegetative state (VS)] and clinical follow-up recovery level (divided into 3 groups: markedly effective, effective and ineffective according to the situation during the 3-month follow-up after operation).

Different SCS frequencies brought different changes to the patient’s cortical electroencephalogram, and there were significant individual differences. Observed at the individual level, the frequencies that cause more obvious positive electroencephalogram regulation effects are 5 Hz (10/24) and 70 Hz (10/24). The positive ratio exceeds other frequency stimuli (20 Hz 5/24, 50 Hz 3/24, 100 Hz 4/24). Compared with the VS group, the MCS group produced a larger electroencephalogram spectrum change under SCS stimulation and the difference in the γ frequency band was statistically significant. However, the correlation between the electroencephalogram spectrum changes in each frequency band and the recovery of clinical follow-up was not found.

Low-frequency stimulation (such as 5 Hz), or high-frequency stimulation (such as 70 Hz) can positively change the brain electrical power of chronic DOC patients, and the two specific frequencies of 5 Hz and 70 Hz should be the preferred choice for clinical stimulation.