We determined whether the relationship between the neuropsychological performance of patients with mild traumatic brain injury (TBI) and their psychopathological characteristics measured by disability evaluation are interrelated. In addition, we assessed which psychopathological variable was most influential on neuropsychological performance via statistical clustering of the same characteristics of mild TBI.
A total of 219 disability evaluation participants with mild brain injury were selected. All participants were classified into three groups, based on their psychopathological characteristics, via a two-step cluster analysis using validity and clinical scales from the Minnesota Multiphasic Personality Inventory (MMPI) and Symptom Checklist-90-revised (SCL-90-R). The Korean Wechsler Adult Intelligence Scale (K-WAIS), Korean Memory Assessment Scale (K-MAS) and the Korean Boston Naming Test (K-BNT) were used to evaluate the neurocognitive functions of mild TBI patients.
Over a quarter (26.9%) experienced severe psychopathological symptoms and 43.4% experienced mild or moderate psychopathological symptoms, and all of the mild TBI patients showed a significant relationship between neurocognitive functions and subjective and/or objective psychopathic symptoms, but the degree of this relationship was moderate. Variances of neurocognitive function were explained by neurotic and psychotic symptoms, but the role of these factors were different to each other and participants did not show intelligence and other cognitive domain decrement except for global memory abilities compared to the non-psychopathology group.
Certain patients with mild TBI showed psychopathological symptoms, but these were not directly related to cognitive decrement. Psychopathology and cognitive decrement are discrete aspects in patients with mild TBI. Furthermore, the neurotic symptoms of mild TBI patients made positive complements to decrements or impairments of neurocognitive functions, but the psychotic symptoms had a negative effect on neurocognitive functions.
The process of brain injury disability evaluation (DE) requires retrospective assessment involving the severities of brain injuries at the initial stage, the process and outcome of medical treatments, and the association between objective medical data and self-reported vague and multiple symptoms. Objective data can easily be obtained from the former two evaluations. However, vague reports of symptoms, such as Post-Concussion Syndrome (PCS) after a traumatic brain injury (TBI), are not reliable and may be debatable, particularly in the context of medico-legal or compensation issues
Brain injury occurs along a continuum of severity. Injuries with a loss of consciousness of less than 30 minutes, Glasgow Coma Scale (GCS)
Figures on the annual incidence of mild TBI are extremely elusive, because of the practices, procedures, and priorities inherent to the medical examination of physical injuries. Obvious signs of gross injuries direct the treating professional's attention to life- and health-threatening conditions, resulting in a de facto lack of emphasis on injuries to the head that are not readily apparent. In addition, the symptoms of a head injury can easily be overlooked and attributed to an emotional reaction to the situation
Among PCS symptoms, twelve months after an injury, 31% of patients reported a psychiatric disorder, and 22% developed a psychiatric disorder that they had not experienced before. Functional impairment, rather than mild TBI, was associated with psychiatric illness. Although it is understandable that patients with psychiatric disorders may want to seek compensation, there is a possibility that this may contribute to patients reporting the presence of a psychiatric illness
DE is a scientific and medical decision-making process, but a scientist must engage in fair, impartial and public decision-making and accept the legal responsibility pertaining thereunto
Furthermore, neurocognitive dysfunctional symptoms and emotional or psychiatric symptoms are interrelated to each other. We therefore investigated how in a DE situation, the neuropsychological performance of patients with mild TBI and psychopathological characteristics are interrelated, and assessed which variable was most influential in the psychopathological characteristics associated with neuropsychological performance among patients with mild TBI.
A total of 1245 patients, with ages ranging from 18 to 80 years old, and who received hospital or ambulant treatment for a brain injury from July 1998 to May 2010 were recruited. After excluding patients who had a neurological abnormality before their brain injury, a secondary head trauma, psychiatric disease, mental retardation, or a history of a chronic disease in the preceding six months, as well as those who did not complete the neuropsychological tests due to serious brain damage, 725 participants remained. Of these, 219 disability evaluation participants with mild brain injury (GCS score 13-15) were selected. These participants were classified into three group, based on their psychopathological characteristics via a two-step cluster analysis using validity and clinical scales taken from the Minnesota Multiphasic Personality Inventory (MMPI)
Classification method of participations was based on an objective statistical classification method for excluding subjective selecting bias by researchers, and then for validating classification processes, classified groups were compared with each other on used variables for the classification. In two-step clustering, to make large problems tractable, in the first step, cases are assigned to "preclusters." In the second step, preclusters are clustered using the hierarchical clustering algorithm. This method has advantage that researcher can specify the number of clusters you want or let the algorithm decide based on preselected criteria
The K-WAIS is psychometric instrument that assesses the potential ability to perform a useful behavior for a certain purpose based on standardized questions and tasks.
The MAS is a comprehensive, standardized memory assessment battery, which is designed to fulfill ordinary clinical assessment needs in a manner that is suitable for various kinds of clinical situations and demands
The K-BNT is a test developed to measure naming ability.
The SCL-90-R is a self-report symptom inventory. It can be used as a primary tool to recognize persons who are in need of professional help. It also has the capability of covering a patient's general symptoms.
The MMPI is an instrument that objectively measures abnormal behavior. Its primary purpose is for psychiatric diagnostic classification but it is also widely used to assess the mental functioning and personality of patients with brain damage.
We performed data processing from the chart reviews using SPSS (MS Windows Release 19.0). Post hoc analyses included frequency analysis (χ2 and Fisher exact tests), two-step cluster analysis, mean difference analysis (one-way ANOVA), and post hoc test (Bonferroni method). Correlational analysis and stepwise multiple regression analysis was used for analyzing relationship psychopathologic characteristics and cognitive function among the clustered mild TBI groups. We considered results to be significant at the
The demographic characteristics of the TBI subjects are presented in
FIQ variance in Group 1 was explained 8.1% by Phobic anxiety (R2=0.081,
Variance in FIQ in Group 1 was explained 15.0% by Paranoia (R2=0.150,
The majority of cases that are encountered in the forensic arena are individuals who may have sustained TBIs. Within TBI, mild TBIs comprise well over half of all reported cases. Many of these injuries occur due to motor vehicle accidents, and the majority of patients with mild TBI are young men between the ages of 16 and 35 years
In this study, all of mild TBI patients showed a significant relationship between neurocognitive functions and subjective and/or objective psychopathic symptoms, but the degree of relationship was with the moderate range. Likewise, decrement or change of neurocognitive function was explained by psychopathologic symptoms related with psychotic symptoms indicated by an elevation of paranoia and schizophrenia scale scores on the MMPI, but neurotic symptoms as obsessive-compulsive, hypochondriac and depressive trends in mild TBI patient had a complementary function to decrements or impairments of neurocognitive function.
Our findings indicated that Group 1 showed a "faking-bad or crying-help" response tendency in the validity scales and severe psychopathological symptoms in the clinical scales of the MMPI and SCL-90-R, but they did not experience a severe intelligence decline compared to the other two groups except for their global memory abilities on the K-MAS. Severe and actual psychopathological problems can lead to a decrease in intelligence or intellectual efficacy, a deterioration of reality testing, premorbid adjustment problems, and depressed scores of comprehension abilities
In this study, we demonstrated a relationship between the neuropsychological performance of patients with mild TBI and their psychopathological characteristics assessed in the DE process. We examined the variables that influenced psychopathological characteristics in neuropsychological performance among patients with mild TBI via statistical clustering of the same characteristics in mild TBI. Certain patients with mild TBI displayed psychopathological symptoms, but these were not directly related to cognitive decrement, and psychopathology and cognitive decrement were discrete aspects in patients with mild TBI. Furthermore, the neurotic symptoms of mild TBI patients were a positive complements to decrements or impairments of neurocognitive functions, but psychotic symptoms had a negative effect on neurocognitive functions.
This work was supported by the 2009 Yeungnam University Research Grant.
Demographic data among 219 disability evaluation subjects with mild traumatic brain injury
n : number of patients, SD : standard deviation, 1 : group 1, 2 : group 2, 3 : group 3
Clinical characteristics among 219 disability evaluation subjects with mild traumatic brain injury
n : number of patients, SD : standard deviation, 1 : group 1, 2 : group 2, 3 : group 3
Comparisons of Symptom Checklist-90-Revised scores among 219 disability evaluation subjects with mild traumatic brain injury
n : number of patients, SD : standard deviation, 1 : group 1, 2 : group 2, 3 : group 3
Comparisons of Minnesota Multiphasic Personality Inventory scores among 219 disability evaluation subjects with mild traumatic brain injury
n : number of patients, SD : standard deviation, NS : not significant, 1 : group 1, 2 : group 2, 3 : group 3
Correlation matrix of SCL-90-R subscales, FIQ, DIQ, GMI, and BNT scores among 219 disability evaluation subjects with mild traumatic brain injury
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Stepwise multiple regression analyses results of SCL-90-R subscales scores for FIQ, GMI and BNT scores
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Correlation analysis results of MMPI subscales, FIQ, DIQ, GMI, and BNT scores among 219 disability evaluation subjects with mild traumatic brain injury
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Stepwise multiple regression analyses results of MMPI subscales scores for FIQ, DIQ, GMI and BNT scores
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Comparisons of FIQ, DIQ, GMI, and BNT scores among 219 disability evaluation subjects with mild traumatic brain injury
n : number of patients, SD : standard deviation, FIQ : full scale intelligence quotient, GMI : global memory index, BNT : percentile score of Korean Boston Naming Test, NS : not significant, 1 : group 1, 2 : group 2, 3 : group 3