Participants
This study was randomized controlled trial. The population of the study included 2000 TBI patients hospitalized in emergency and neurosurgery departments of Shahid Beheshti Hospital, Kashan, Iran, in 2017. They were selected using the convenience sampling method.
Sample size
With regard to limitations in sampling and rehabilitation of patients with brain damage, considering the 95% confidence and 80% test capability, using the following formula, the number of samples in each group were calculated (n=16).

Selection criteria
All the patients were given a written explanation of the study protocol and were invited to participate in the project if they met the following criteria: (1) 18-50 years old; (2) a Glasgow Coma Scale score between 13 and 15; (3) a post-traumatic amnesia (PTA) more than one hour; ( 4) localized or disseminated brain damage made by an external mechanical force; (5) brain imaging findings such as skull fracture or acute brain injury; (6) no history of substance abuse or previous neurological psychiatric disorders; and (7) informed consent to take part in the project.
Exclusion criteria included (a) lack of willingness to continue the research; (b) the absence of more than one session; (c) starting a secondary therapy; and (d) the use of other substances (except alcohol, and caffeine) during all stages of research.
Procedure and randomization
Patients who met the inclusion criteria (N = 48) were evaluated with psychological and cognitive tests. Then, patients were randomly assigned to tDCS or MBSR or control group. In order to handle the intervention sessions, each of the tDCS and MBSR groups was divided into two groups. Both MBSR and tDCS therapies consisted of eight sessions. Patients were reassessed at baseline, post-treatment (immediately after the last treatment session), and two months after the treatment.
Measurements
Mental fatigue scale
The mental fatigue scale (MFS) is a multidimensional self-report questionnaire with 15 items. It consists of cognitive, psychological, sensitive symptoms, and sleep quality subscales. This questionnaire was prepared by Johnson et al. in 2009-2010 to examine the dimensions of mental fatigue in patients with neurological disorders, and its Cronbach’s alpha coefficient was reported to be 0.9. The score range is from 0 to 42, and higher scores reflect a more severe symptom (14, 15). The validity and reliability of the Persian version of the scale were assessed. In the current study, the MFS showed a high internal consistency (α = .91) (16).
Quality of life
The World Health Organization Quality of Life- BREF (short version) (WHOQOL-BREF) was developed for measuring quality of life. In Iran, it has been translated and standardized according to scientific principles, and its reliability and validity have been approved to be used in Persian population. Internal consistency was measured using Cronbach's alpha of the four aspects, which was 0.77 in the patient group and 0.73 in the healthy group. The questionnaire consists of 26 items. Participants' scores range between 4 and 20 (17).
Aggression scale
The new version of the Buss-Perry Aggression Questionnaire (BPAQ) is a self-rating scale which has 29 items answered on a 5-point Likert and has four subscales of physical aggression (PA), verbal aggression (VA), anger (A) and hostility (H). The results of the test-retest coefficients for the four subscales (9 weeks apart) were 80.0 to 72.0 and the correlation between the four subscales ranged 38.0 to 49.0. The internal validity of the scale was measured using Cronbach's alpha coefficient; these coefficients for the internal consistency of the subscales of physical aggression, verbal aggression, anger, and hostility were 82.0, 81.0, 83.0, and 80.0, respectively (18).
Treatments
tDCS
The tDCS electrical stimulation was delivered using a tap-water soaked sponge pair of rubber carbon pads (each 10.5 cm²). The pads were fixed by rubber bands on the heads of the participants. Anodal stimulation (1.5 mA, 20 min) was carried out on (left frontal areas) F3 through 10 sessions of tDCS treatment (three times a week). The cathodal stimulation was fixed over (right DLPFC) FP2. Both anodal and cathodal stimulations were delivered by an electrical stimulator tDCS device (Active dose II). Safety guidelines specified by Nitsche et al. (2003) were taken into consideration (19). The participants were informed that this treatment would not be considered as a first-line treatment for TBI. The related information sheets included the explanation for frequent adverse effects of tDCS (itching and tingling skin sensation, skin reddening, and headache). With regard to group separation (sham and active), no differences in information were presented. The sham tDCS mode started with a variable ramp-in and ramp-out phases. This was followed by an impedance control mode with small measuring pulses of 100e200 mA amplitude every 400e550 ms for the same period as in the active condition, and ended with another ramp-in and ramp-out phase. The tDCS was carried out passively and the participants did not engage in an online task.
MBSR
MBSR was delivered by two doctoral clinical psychologists who had completed their 1-year full-time MBSR training in Kashan University of Medical Sciences. They implemented an 8-week program of mindfulness meditations developed by Jon Kabat-Zinn (1996). Groups of eight patients met for 8 sessions Each session lasted for 2 hours. In order to support the practice, each participant was presented with a MBSR workbook. The workbook included descriptions for mindfulness exercises. It also included prerecorded audio files to support ongoing practice (20). The eight therapy sessions followed the program outlined in Table 1.
Table 1.
MBSR sessions
Session
|
Content
|
Pre-session and preparation
|
Seeking familiarity with participants and make a rapport. Discussion about treatment and MBSR approach. Trying to identify obstacles and solving them.
|
1
|
Body scan, mindful breathing, and mindful eating.
|
2
|
Body scan, mindful breathing, mindful eating, and mindful tooth brushing.
|
3
|
Body scan, sitting meditation, completing pleasant events calendar, continuing infuse mindfulness into daily life activity.
|
4
|
Everyday yoga, STOP technique, continuing infuse mindfulness into daily life activity.
|
5
|
Body scan, yoga, and sitting meditation in alteration, brain and meditation, loving kindness meditation, completing Communication Calendar during week, continuing infuse mindfulness into daily life activity.
|
6
|
Body scan, yoga, and sitting meditation in alteration, introducing conflict resolution styles, AH-FOWL exercise, continuing infuse mindfulness into daily life activity.
|
7
|
Body scan, yoga, and sitting meditation in alteration, pain process, learning about emotions, continuing infuse mindfulness into daily life activity.
|
8
|
Body scan, yoga, and sitting meditation in alteration, continuing infuse mindfulness into daily life activity, writing about short-time and long-time goals.
|
Data analysis
Data were analyzed using descriptive statistics (mean, frequency and standard deviation), mixed Repeated Measures ANOVAs, and Levene and Kolmogorov-Smirnov tests by the SPSS software version 23.
Ethical considerations
All participants were asked to complete an informed consent from prior to participation in the study. This study was approved by the Ethics Committee of Kashan University of Medical Sciences (code no.). Moreover, the registered codes in RCT system is TCTR20180827003.