@2024 Afarand., IRAN

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ISSN: 1027-1457    Scientific Journal of Forensic Medicine 2020;26(2):93-99

Background
…[1]. Based on the diagnostic estimates of 75% [2] to 95% [3], mild traumatic brain injury (MTBI) has the highest rate of traumatic brain injury and it is one of the most common causes of injury in the central nervous system.
Previous Studies
...[5-7]. Traumatic brain injury can have many complications. One of its complications is cognitive disorders, which is a common complication in various types of traumatic brain injury. …[8-11]. Inhibition is defined as an individual's ability to monitor and control responses and includes two types of cognitive and behavioral inhibition [12]. Cognitive inhibition refers to the mind's ability to prevent entering task-irrelevant information to the mind's active state [13]. Behavioral inhibition that shows a tendency toward distress and nervousness in new situations [14] is a person's ability to stop or delay an action aimed at controlling unwanted and reactive behaviors [15]. …[16-32]. According to the research results, however a percentage of MTBI casualties show a relative recovery within a few weeks, MTBI may initiate a complex condition called post-traumatic stress disorder and cause continuous symptoms for the patients at the same time, including cognitive and psychological complaints [8]. According to McCreery et al. [33] and Panour et al. [34], 55% and 79.2% of these patients, respectively, tolerate long-term cognitive complications due to mild injury for several months to a year [35] and more than one year [36]. Scientific results show that MTBI can provide continuously multiple problems in the cognitive, emotional, sensory, and motor domains for the injured [37]. Therefore, the risk of mild brain injury should not be underestimated, because the post-traumatic injury is not limited to severe injury and can still exist in moderate and mild injury [1] and regardless of the severity of the damage [8], causes a variety of physical, behavioral, emotional [36], legal, judicial [38], and cognitive [39] problems and disabilities for the injured. These symptoms, which begin immediately after the injury and tend to subside over time, may affect the patient for a year or years after the injury and challenge the patient's daily and professional performance [4].
Aim(s)
This study aimed to compare cognitive and behavioral inhibition in healthy individuals with MTBI patients, which a year has passed since their injury.
Research type
This present descriptive research is a causal-comparative study.
Research society, place and time
This study was performed in February 2017 to October 2016 between healthy men with male MTBI patients, who were hospitalized in the Haft-e-Tir Martyrs hospital located in Shahr-e-Rey city and the Baqiyatallah hospital located in Tehran.
Sampling method and number
The statistical sample of the study included 64 healthy men and 51 male MTBI patients, how were hospitalized in the Haft-e-Tir Martyrs hospital located in Shahr-e-Rey city and the Baqiyatallah hospital located in Tehran, which was selected using the available sampling method. Inclusion criteria to the study were non-dependence to drug and alcohol, no more comorbidities, having a minimum age of 30 and a maximum age of 55 years and having a minimum level of literacy in the first grade of middle school and a maximum level of associate degree. All participants completed the written consent form for participate in the study before performing the test. During the test, 3 participating patients refused from cooperating and completing the test due to the physical weakness and inadequate mental condition and finally, 48 patients with mild brain injury and 64 healthy men constituted the sample size. The sample size was determined 44 people in each group using G* Power software considering the statistical power of 95%, the effect size of 0.5, and the significance level or 5% alpha.
Used devices&materials
The complex Stroop test was used to assess participants' cognitive and behavioral inhibition. John Ridley Stroop created this test in 1935. The Stroop test has been used in various studies in various clinical groups to measure impulse control and inhibitory strength, selective attention, and cognitive flexibility through visual processing [40]. This test can identify defects in the prefrontal cortex that is responsible for various brain functions such as cognitive functions, response inhibition, risk-taking and impulsive behavior, emotion management, and so on. Therefore, it is common to use this test to measure subtle executive function defects in people with traumatic brain injury. Due to the different applications of the Stroop test, many changes have been made to the original model in terms of the number of colors displayed, the timing of the stimulus display, and the time interval between the stimulus display. In the present test, complex Stroop software designed by the Sina Psychometric Institute was used. In this software, different time intervals between the displays of stimuli are used to prevent habituation in response. These times include 550, 650, 750, 850, and 950 thousandths of a second. The use of this method prevents pattern matching in the individual because if a method is continued with the time of providing a uniform stimulus of cognitive control resources and the effect of adaptation will result in faster and better results in performing the heterogeneous stage. The variables of consonant reaction time, inconsistent reaction time, number of consonant errors, and number of inconsistent errors, interference score, and the sum of errors from complex Stroop test subscales were evaluated to measure cognitive inhibition and impulse control. Regarding the validity of this test, Sina Psychometric Institute has reported that the validity of this test has been assessed with the help of experts in psychology, cognitive sciences and cognitive ergonomics. In general, studies conducted with the Stroop test indicate the appropriate validity of this test in measuring the inhibition of adults and children. The reliability of the Stroop test was reported in the range of 0.80-0.91 through retesting. Kolmogorov-Smirnov test was used to evaluate the normality of data distribution and the performance of the two groups was compared using multivariate analysis of variance by SPSS 21 software.
Findings by Text
112 patients were studied, which 48 (42.9%) and 64 (57.1%) of them were in the MTBI patient group and the healthy group, respectively. The average age in the group of MTBI patients and healthy individuals was 41.8±17.25 and 41.8±81.61 years, respectively. Most of the participants in the study placed in the age group of 30-35 years as well as they had first and second grade education (Table 1).Mean scores of consonant reaction time, number of consonant errors and inconsistent reaction time (p<0.05) and number of inconsistent errors, interference score and sum of incorrect responses (p<0.01) in MTBI patients were significantly higher than healthy individuals (Table 2).
Main comparison to the similar studies
The findings of this study showed that there was significant differences in the scores of consonant and inconsistent reaction time, number of consonant and inconsistent errors, interference score and the sum of incorrect answers between the two groups, which indicates poorer cognitive and behavioral inhibition in MTBI patients. …[41]. This result is consistent with many findings of previous researchers [8, 42-44], regarding cognitive disorders and poor performance of MTBI patients. Also, the results of considering the persistence of cognitive disorder in MTBI patients after one year of injury are consistent and confirming the previous studies [35]. According to scientific reports, forehead injury is the most common in traumatic events [6], and it leads to the destruction or defect in cognitive functions. According to Bergerson et al. [45], this defect causes a variety of problems such as disorder in planning, lack of decision-making power to initiate a behavior, difficulty in stopping responding, impulsivity, and lack of cognitive and behavioral inhibition. A normal life requires all of the above abilities. Therefore, the lack or deficiency of any of these capabilities can challenge people's daily functioning and can have the adverse effects on the patient's social life and impose many problems on the individual and society.
Suggestions
It is suggested that the limitations of this research be considered in future studies as much as possible to obtain more convincing results with wider generalizability.
Limitations
The unavoidable limitations in this study can affect the results and they need to be considered for generalizing the results. First, the sample selection of this study was not completely random and the available method was used. Also, as in other clinical studies, it was not possible to use a large statistical sample. This study was performed only on MTBI male patients; so its findings cannot be generalized to women and other types of brain injury.
Conclusions
MTBI can make disorders in the function of the frontal lobe of the brain after one year and effect on the executive functions under the command of this region, especially the cognitive and behavioral inhibition of patients.
Acknowledgments
The present article is retrieved from the doctoral dissertation of the responsible author, which has been conducted with the cooperation of respectable officials, staff, and patients of the Haft-e-Tir Martyrs hospital of Shahr-e-Rey city and the Baqiyatallah hospital in Tehran province. All of them are thanked and appreciated.
Conflict of interest
No conflict has been reported by the authors.
Ethical Permissions
This study was conducted with the ethics id of IR.UT.PSYEDU.REC.1398.004.
Funding Sources
No case has been reported by the authors.

TABLES and CHARTS

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