A comparative study of repetitive transcranial magnetic stimulation at different frequencies in arousal for coma patients after brain stem injury

Objective To compare the effect of repeated transcranial magnetic stimulation (rTMS) at different frequencies acting on left dorsolateral prefrontal cortex (LPFC) on arousal for coma patients after brain stem injury. Methods Ninety-nine patients with coma resulted from brain stem injury, admitted to our hospital from February 1, 2015 to April 10, 2018, were chosen in our study. Among them, 30 patients weren't treated with rTMS (control group), 33 patients were treated with 10 Hz rTMS (10 Hz rTMS treatment group), and 36 patients were treated with 20 Hz rTMS (20 Hz rTMS treatment group); treatments lasted for 20 d. All patients received routine coma arousal treatment. Glasgow coma scale (GCS) scores, electroencephalogram (EEG) grading, brainstem auditory evoked potential (BAEP) grading and incidence of adverse reactions were compared among the three groups before and after treatment. Results Before treatment, there were no significant differences in GCS total scores, language response scores, motor response scores, eye opening reaction scores, EEG grading and BAEP grading among the three groups (P>0.05). The total GCS scores, and scores of language response, motor response and open eye response of patients in the 20 Hz rTMS treatment group and 10 Hz rTMS treatment group after treatment were significantly higher than those in the control group (P<0.05); the total GCS scores and motor response scores of patients in the 20 Hz rTMS treatment group were significantly higher than those in 10 Hz rTMS treatment group after treatment (P<0.05). After treatment, patients in the control group, 10 Hz rTMS treatment group, and 20 Hz rTMS treatment group showed statistically significant differences in EEG grading and BAEP grading (P<0.05). The incidence of adverse reactions in the 20 Hz rTMS group (19.4%) was statistically higher than that in the 10 Hz rTMS group (3.0%, P<0.05). Conclusion High-frequency rTMS has an awakening effect on patients with coma resulted from brain stem injury, and the coma awakening effect of 20 Hz rTMS is partially better than that of 10 Hz rTMS, but it has the risk of increasing side effects such as epilepsy and scalp burn. Key words: Repetitive transcranial magnetic stimulation; Coma arousal; Brain stem injury