1. Introduction
ne of the most common cognitive problems after traumatic brain injury is impaired executive function. The recovery after traumatic brain injury takes place one year after injury; after this period, the brain injured patient faces an uncertain future. In some patients, improvement is observed even 5-10 years after injury, while in some patients the injury is worsened [7]. It is associated with cognitive dysfunction as a result of impaired information processing, memory, attention, planning, and executive function. The aim of this study was to evaluate cognitive impairment in men with a history of Severe Traumatic Brain Injury (STBI) compared to healthy men.
2. Materials and Methods
This causal-comparative study (Ethical approval code: IR.UT.PSYEDU.REC.1398.004) was conducted from February 2017 to July 2019 on two groups of individuals; 20 male patients aged 30-55 years having STBI in the past one year and admitted to the intensive care units of two Shohaday-e-Haftom-e-Tir and Baqiyatallah hospitals, in Tehran, Iran, and 64 healthy men that had met all inclusion criteria (age of 30-55 years, no addiction to drugs and alcohol use, no other concurrent diseases, educational level ranging from first grade middle-school education to associate degree). After explaining the study method and Objectives to participants and obtaining a written informed consent from them, their demographic characteristics were recorded via interview, and then they underwent the Wisconsin Card Sorting Test (WCST) which was taken by a clinical psychologist. This test a reliable tool for assessment of cognitive impairment in adults and can measure concept formation and reasoning abilities. The professional manual for the WCST was written by Heaton et al. [32]. It has been found to be sensitive to frontal-lobe dysfunction, providing a clinical measure of abstract thinking and the ability to shift cognitive sets. Inter-rater reliability of this test ranges from 0.91 to 0.96 and its generalizability coefficients ranges from 0.39 to 0.72. The average concurrent validity regarding the agreement between this test and other measures of concept formation is 0.83. The Cronbach’s alpha of WCST showed has accepatable reliability in Iranian samples. The WCST responses were compared between the two study groups regarding the presentation of cards and the presentation of feedback signals. Data were analyzed in SPSS V. 21 software using Mean and Standard Deviation (SD) and ANOVA. 
3. Results
The Mean±SD age of STBI patients and healthy men was 40.10±9.61 and 41.81±8.60 years, respectively; most of them (35.7%) had 35-30 years of age, while minority of them (11.9%) were at an age range of 41-45 and 46-50 years. Most of them (34.5%) had first-grade to third-grade high school education, while minority of them (7.1%) had associate degree. The overall WCST score was lower in patients than in healthy men. The mean number of categories completed in patients (1.00) was lower than in healthy subjects (2.47), and there was a significant difference between patients and healthy men (P<0.01). Descriptive statistics of WCST scores for the men with and without STBI are presented in Table 1. 


The results showed that the correct responses, response time, number of trials to successfully complete first category, and conceptual level responses were lower in patients with STBI than in healthy subjects, and patients had more perseverative errors than healthy subjects. Patients had a mean correct response of 21.40±5.05, while for the healthy group it was 31.03±6.21 (Table 1). 
ANOVA was used to determine whether there were any statistically significant differences in the executive functions between the two groups. The results showed a significant difference between two groups in the number of categories completed (F(1,112)=19.82, P<0.001), perseverative errors (F(1,82)=41.59, P<0.001), correct response (F(1,82)=39.76, P<0.001), wrong responses (F(1,82)=36.95, P<0.001), response time (F(1,82)=12.50, P<0.001), number of trials to successfully complete first category (F(1,82)=36.83, P<0.001), and conceptual level responses (F(1,82)=19.02, P<0.001). 
4. Conclusion
There was a significant difference between men with STBI and healthy ones in the executive functions. STBI can cause different psychological consequences, including impaired functions in Orbitofrontal Cortex (OFC) [24]. Impairments in memory, attention, executive functions, and behavioral control followed by injury to the frontal and temporal lobes, are particularly troublesome [13]. Studies have suggested that OFC acts as a critical frontal brain area that informs the downstream regions about the need to suppress the behavior. Evidence for this arose when damage to OFC was shown to promote disinhibition operationalized as perseveration during extinction tasks. Many of these studies suggest that OFC provides a type of inhibitory signal that dampens behavioral responding when such control is necessary for accurate performance. Study of the patients with STBI can increase our knowledge of STBI, and help improve its treatment and increase rehabilitation efforts.

Ethical Considerations
Compliance with ethical guidelines
This study ethically approved by Alzahra University, Tehran, (Code: IR.UT.PSYEDU.REC.1398.004).

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Authors' contributions
Conceptualization, writing: Mohaddeseh Mozaffari, Mehrangiz Peyvstegar; Methodology: Mehrangiz Peyvstegar, Mohaddeseh Mozaffari, Siamak Soltani; Investigation: Mehrangiz Peyvstegar, Mohaddeseh Mozaffari, Seyed Abolghasem Mehrinejad; Editing: Seyed Abolghasem Mehrinejad, Siamak Soltani; Resorrces, funding, acquisition: All author; Supervision: Mehrangiz Peyvstegar, Mohaddeseh Mozaffari, Seyed Abolghasem Mehrinejad.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
The authors would link to thank all supervisors and staff of Shohaday-e-Haftom-e-Tir and Baqiyatallah Hospitals, and also would link to thank all STBI patients fot thei cooperation.


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