Fig. 2

Changes in sleep pattern of VS patients with sleep cycles before and after treatments. A Total sleep time of VS patients with sleep cycles before and after treatments. Sleep structure of VS patients with sleep cycles in tDCS group (B) and sham group (C). D NREM sleep 2 stage of VS patients with sleep cycles before and after treatments. E Sleep pattern of VS patients at baseline in tDCS group. F Sleep pattern of VS patients after tDCS. Other Sleep stages of VS patients with sleep cycles before and after treatments, including NREM sleep 1 stage (G), slow-wave sleep (H), REM sleep stage (I). *P < 0.05, n.s: no significant difference; P values were determined using analysis of covariance (ANCOVA) and age was included as a covariate; TST: total sleep time; W: wake stage; N1: nonrapid eye movement sleep 1 stage; N2: nonrapid eye movement sleep 2 stage; SWS: slow-wave sleep; REM: rapid eye movement sleep; tDCS: transcranial direct current stimulation; VS: vegetative state