MASTERTHESE
Executive functioning in children and adolescents with singular and multiple trauma UNIVERSITY OF AMSTERDAM
STUDENT
name : Elena Marie Murray
student number : 5996724
address : Van Speijkstraat 151
telephone number : 0049 152 561 35 916
e-mail address : elena.m.murray@gmail.com
TUTOR
binnen ProgrammaGroep : Marija Maric
external tutor : Ramon Lindauer
2nd beoordelaar : Pier Prins
onderzoeksinstelling / locatie : De Bascule DATUM :19.02.2014
Content
1. Abstract………...4
2. Introduction………..5
2.1. Trauma……… ……….. 5
2.2. Executive functions……….... 6
2.3. Trauma and gender………...10
3. Method……….11
3.1. Participants and Procedcure….………11
3.2. Measures ………...…12
4. Results………..13
5. Discussion………...………14
5.1. Conclusion………14
5.2. Limitations………17
5.3. Future research and clinical implications………..………..17
Abstact
This study aims to examine the relationship between different executive functions and singular and multiple trauma in a group of traumatized children and adolescents. Parents of 30 children with an age span of 7 – 17 years (16 girls and 14 boys) and either a singular or multiple trauma completed the BRIEF in order to measure executive functioning. Results revealed that children suffering from multiple trauma score higher on the BRIEF than children with a singular trauma. These results indicate that multiple traumatized children have more impaired general executive functions, inhibitory control ad flexibility than children suffering from singular trauma. However, these differences were not statistically significant, therefore, the hypothesis that children suffering from a multiple trauma have more impaired general executive function, inhibitory control, working memory and flexibility than children suffering from singular trauma must be rejected.
Introduction
A variety of studies show that executive functions are crucial to the behaviour of children (Barkley, 1997; Brocki & Bohlin, 2004; Welsh, Pennington, & Groisser, 1991; Weyandt & Willis, 1994). It is known by now, for example, that the domain of executive functions plays a major role in developmental disorders, such as ADHD, conduct disorder and autism spectrum disorders (Pennington & Ozonoff, 2006). Despite this known relationship between executive functions and emotional problems in children, only few studies have been conducted with regards to the relationship between executive functioning and trauma in children. The little research that has been done indicates that children who were exposed to trauma tend to perform more poorly on measures of executive functioning (Beers & De Bellis, 2002). In this study, I aim to examine the relationship between executive functions and singular and multiple trauma in a group of traumatized children and adolescents. Understanding this relationship has significant clinical relevance: Insufficient executive functioning reveals itself especially on a behavioural level, such as problems at school due to a lack of concentration. Understanding which type of trauma is more related to a deficiency in executive functioning makes it possible to precisely adjust therapy to individual problems of the traumatized child or adolescent. Furthermore, understanding which specific executive functions are impaired can help us to explicitly focus on particular impairments of executive functioning during therapy.
Trauma
Trauma can be defined as an individual experience of a singular event (singular trauma) or as a lasting condition (multiple trauma) in which the individual's ability to integrate their emotional experience is overstrained and the individual experiences are perceived a threat to the persons life, bodily integrity, or that of a caregiver or family (Saakvitne, Gamble, Pearlman, & Lev, 2000). A traumatic event can lead to Post Traumatic Stress Disorder (PTSD) in which fear and related symptoms, such as flashbacks, avoidance of threatening stimuli and anxiety continue to be experienced long after the traumatic event. The diagnostic symptom cluster of the DSM-IV (American Psychiatric Association, 2000) can be used to diagnose both singular and multiple PTSD in traumatized children and adolescents of all ages in the same way as it is used to diagnose traumatized adults (Mash, 2003). There are two types of PTSD we refer to when exploring trauma: Singular PTSD, also known as singular trauma, refers to anxiety due to one traumatic incident that causes major distress. Some examples of traumatic events that might cause singular PTSD include a car accident, a natural disaster or death of someone close to the individual. Typical symptoms of singular PTSD are flashbacks, recurrent bad dreams, avoiding reminders of the event, etc. The term multiple PTSD on the other hand refers to trauma in which the individual suffers distress from several traumatic incidents. Repeated physical abuse such as sexual abuse and domestic violence, emotional abuse, such as neglect as well as war and political suppression are
representative conditions that might trigger multiple PTSD in children and adolescents (Cook et al., 2005). Persistent exposure to traumatic events during childhood and adolescence may lead to emotional dysregulation and impairment in associated skills in effective interpersonal behaviours. Cloitre et al. (2009) point out that disturbances in self-regulation can lead to both overactivation and deactivation of emotions and interpersonal behaviours. They state that this over- and deactivation can be expressed by dysphoria and anger as well as dissociation in emotions; and on an interpersonal level by behaviours that are aggressive or dependent, as well as those that are distant and avoidant (Cloitre et al., 2009). Experiencing a trauma and the resulting emotional dysregulation and problems with interpersonal relevance can have far-reaching negative consequences for the children or adolescents and can lead to life-long complications, such as psychiatric and addictive problems, chronic medical illnesses as well as legal and family problems (Cook et al., 2005). Thus, especially traumatic incidents that are chronic lead to more severe negative outcomes than traumatic events of short duration (Mash, 2003).
Executive functions
The term ‘executive functions’ is used in neuroscience and neuropsychology and refers to cognitive processes that are applied in order to control behaviour, taking environmental conditions into account (Pennington & Ozonoff, 2006). Executive functions determine mental functions regarding Inhibition, Shift, Emotional Control, Initiation, Working Memory, Planning, Organization of Materials and Self-monitoring (Elliott, 2003). Cooper-Kahn & Dietzel (2008) provide useful definitions of these eight different executive functions (see Table 1):
Table 1. Description of executive function with example.
Executive functions Definition Example
Inhibition Refers to the ability to
suppress inappropriate precipitate reactions to a certain stimulus when needed.
Being able to oppress impulses such as raising voice at an authority when things do not go the way as one expected
Shift Generally refers to the ability
to think in a flexible way and being able to react
adequately to quickly changing situations.
Being able to adapt
cognitively in a work setting where a complete new solution strategy is applied in an attempt to solve a
problem. Emotional control Generally refers to the ability
to regulate and control ones emotional responses by rationally reflecting on the stimulus that might cause the emotional response.
Being able to understand that the disappointment about a cancelled plan should not lead to aggressive behaviour
Initiation Usually refers to the ability to begin with a task and thereupon generate ideas and apply problem-solving strategies.
Starting to find a job and beginning to send out CV’s in order to get a Job interview.
Working memory Generally refers to the
temporary storage of task-relevant information in the brain. It usually plays an active role in cognitive thinking processes.
Keeping in mind the doctors room number, after asking for it at the hospital reception.
Planning Refers to the ability to
adequately plan the order and amount of work that a certain activity requires.
Systematically planning an evening in which friends got invited for dinner, regarding invitations, cooking, laying table etc.
Organization of Materials Refers to the ability to organise the order and requirements that a certain task demands.
Laying the table for the dinner in a meaningful manner, considering the order and kind of food that is going to be served. Self monitoring Refers to the ability to reflect
on one’s actions and evaluating these actions in the light of a certain standard that might be expected.
Understanding that giving a classroom presentation being completely unprepared might cause unsatisfactory results, such as bad feedback and marks.
Most of the current research on trauma and executive functioning is based on an adult sample. In these studies it was constantly found that adults exposed to multiple trauma do have impaired executive functions (El-Hage, Gaillard, Isingrini, & Belzung, 2006; Stein, Kennedy, & Twamley, 2002). In studies on singular trauma a similar, though less strong effect of impaired executive functioning was found (Parslow & Jorm, 2007). Even though there is a lack of research on sample groups of children and adolescents a study conducted by Beers and Bellis (2002) did compare the neuropsychological functioning of 14 children with maltreatment PTSD to the neuropsychological functioning of 15 healthy children. The results of that study reveal that maltreated children perform more poorly on neuropsychological measures of executive functioning than children that have not been subject to maltreatment. However, executive functioning was only measured by neuropsychological measures, such as the ‘Wisconsin Card Sorting Test’ (Grant & Berg, 1948) and not on a behavioural level by means of a screening tool. Also, it has not been examined to what extent the amount of the traumatic experiences has influence on the level of impaired executive functions. Maltreatment, such as sexual abuse can occur as a singular event or manifest itself as a permanent condition, such as child neglect with multiple traumatic events. Other previous studies, such as that of DePrince et al. (2009), are usually based on
traumas that stem from prolonged exposure to traumatic events, such as growing up with familial violence or child maltreatment. DePrince’s et al. study suggests that if the child is exposed to multiple traumatic incidents, executive functions are indeed impaired (DePrince, Weinzierl, & Combs, 2009; Schoeman, Carey, & Seedat, 2009). However, DePrince et al. (2009) compare familiar to non-familiar trauma and does therefore not explicitly make a difference between duration and frequency of trauma exposure, but rather between the nature of trauma exposure (familial vs. non-familial trauma). Also, the children completed a battery of neuropsychological tests to assess, processing speed, working memory, auditory attention, behavioural inhibition, and interference control in an experimental setting, but were not examined in their daily common functioning by means of a screening instrument.
There are several possible explanations for the association between PTSD and executive functions. One explanation focuses on a rather psychological approach that employs cognitive mechanisms such as information processing. Executive functioning, among other cognitive strategies, may contribute to global changes in information processing in order to avoid threat-related cues (DePrince, 2005). Children that are persistently exposed to traumatic situations are usually powerless to control the distressfulness they are exposed to, such as familial violence etc. The constant awareness of this could result in destructive outcomes, such as increased stress, decreased attachment to caregivers, or increased conflict with caregivers (Freyd, Deprince, & Gleaves, 2007). Therefore it is possible that the ability to decrease attention to such threatening cues in fact represents a subjectively perceived advantage to the children by giving them the opportunity to cognitively direct their attention away from the inescapable harm (DePrince & Freyd, 1999).
Another explanation highlights the neuropsychological mechanisms of neurological development of traumatized children: A neuroimaging study of traumatized adults indicated that the prefrontal cortex shows a decreased activation, which consequently leads to impaired executive functioning (Van der Kolk, 2006). Up until today it is still not entirely clear as to what role the frontal cortex precisely plays and whether the frontal lobe is just a Prerequisite of executive function or if it actually carries out and regulates executive functions (Alvarez & Emory, 2006). It is however, clear that that for unimpaired executive functioning an intact frontal cortex (frontal lobe, especially the prefrontal cortex) is a crucial factor. The fact that both, children with impaired executive functioning and children who are traumatized show a decreased activation in the prefrontal cortex underlines the point that this brain area obviously plays an essential role in the relationship between impaired executive functioning and trauma. During brain development in children, brain areas such as the prefrontal cortex are especially vulnerable to stress and trauma (Teicher et al., 1997). These neural structures are influenced by the biological stress systems, such as cortisol release, that as a consequence involve the secretion of various neurotransmitters, such as norepinephrine and dopamine (De Bellis, 2001). The dopamine and norepinephrine levels increase during exposure to prolonged stress, probably leading to prefrontal cortex dysfunction and then to symptoms of inattention and impairment in executive functions (Arnsten, 1998).
As shown in table 1 executive functioning covers a multitude of everyday skills. Some specific executive functions are more associated with developmental cognitive disorders than others. ‘Inhibition’ and ‘Working Memory’, for instance were found to be more impaired in children and adolescents suffering from ADHD, when contrasted against healthy control groups (Bull & Scerif, 2001). Children with autism typically also show problems on executive tasks requiring ‘Working Memory’ and ‘Shifting’ (Bull & Scerif, 2001). Having a closer look at specific executive function in traumatized children would give us another interesting insight into the underlying association between executive functions and type of traumatic events. In the following particular attention will be therefore paid towards representative executive functions such as ‘Inhibition’, ‘Working Memory’ and ‘Shifting’. Especially ‘Inhibition’ and ‘Working Memory’ appear to be considerably restricted in cognitive functioning of adults who have been exposed to traumatic events. Constrained performance on measures of ‘Working Memory’ as well as inhibitory control has been found in combat related PTSD when compared with a non-trauma control group (Vasterling, Brailey, Constans, & Sutker, 1998). In this study 43 veterans, of which 19 met the criteria of PTSD, undertook neuropsychological tests in order to measure working memory’ and inhibitory control’. Inhibitory control was detected by means of an attention test battery developed by Mirsky et al. (1991), including tests such as the Stroop Task, the Go-Nogo Task, Letter Cancelation, and Attention Network (ANT) Tasks. Working memory was detected by means of the AVLT (Auditory-Verbal-Learning Task); (Schmidt, 1996) and the CVMT (Continuous Visual Memory Test); (Larrabee & Curtiss, 1995). Participants suffering from PTSD scored significantly lower on those tasks compared to participants who did not suffer from PTSD. However, this relation again was only found in an adult sample. It is currently unclear as to r how childhood and youth PTSD is related to working memory and inhibitory control.
In some studies executive functioning concerning cognitive ‘flexibility’ or ‘shifting’ in adults who were exposed to a traumatic event, was found to be disrupted (Beckham, Crawford, & Feldman, 1998), while in others it was not (Twamley, Hami, & Stein, 2004). In those studies a classical neuropsychological task, the Trail-Making Test (TMT) was used to measure ‘shifting’. During the TMT, participants are supposed to connect ‘dots’ while switching between letters. In Beckaham’s et al. study the TMT-scores of 45 combat veterans, suffering from PTSD were compared to the scores of 45 veterans without PTSD. A significant difference in performance between veterans with and without PTSD regarding ‘shifting’ was found, as traumatized veterans scored significantly lower on the correspondent tasks. However, in this study some of the veterans were medicated with antianxiety medication in order to alleviate their PTSD symptoms. Since Beckam et al. (1998) missed out on controlling for medication, it was not clear to what extend medication had influence on the results. In a replication of Beckams et al. (1998) study, Twamely et al. (2004) no significant variance in TMT performance was found, while controlling for substance use. Neuropsychological research therefore seems to provide consistent support for impairment of inhibition and working memory, while it still seems to be unclear to what extent ‘shifting’ is impaired in adults suffering from PTSD. Moreover, until
now it has not been tested to what extent ‘shifting’ is impaired in children who have been subjected to a traumatic event.
Trauma and gender
According to epidemiological studies girls tend to have more concurrent comorbidity and homotypic and heterotypic continuity regarding all psychiatric disorders than boys (Costello, Mustillo, Erkanli, Keeler & Angold, 2003). Gender also plays an important role when it comes to the diagnosis of PTSD. Although adult males are more often confronted with traumatic events across their lifespan, adult females tend to receive a PTSD diagnosis more often (Tolin & Foa, 2006). Apparently, women and men differ in the types of the traumatic events. Whereas men usually witness physical violence and accidents, women are more often confronted with sexual abuse or harassments (Gavranidou & Rosner, 2003). Also, studies based on a child sample reveal that girls suffer from higher PTSD symptom levels than boys (Green et al., 1991) and that traumatized girls are at a higher risk to develop PTSD that boys who witnessed traumatic events (Green et al., 1991; Walker, Carey, Mohr, Stein, & Seedat, 2004). Until now it has not been tested to what extent gender might affect the relationship between the type of trauma and executive functioning in children. Assuming that trauma symptoms and executive function are related it would be of value to investigate whether gender has a moderating effect on this relationship.
The aim of this study is to examine to what extent the executive functions of children with either a singular or multiple trauma differ. Based on the results of recent studies with an adult sample it is assumed that prolonged stress may have a greater damage on the neurobiological and cognitive development of children than one-time traumatic event (De Bellis, 2001). It is therefore proposed that multiple traumas are more associated with cognitive disruption than singular trauma. The development of areas in the frontal lope, such as the prefrontal cortex can especially suffer from exposure from prolonged stress. The frontal lobe on the other hand also plays a highly critical role in the development of executive functions. The first hypothesis is therefore that children suffering from multiple traumas have more impaired executive functions than children suffering from a singular trauma (Alvarez & Emory, 2006; Teicher et al., 1997; Van Der Kolk, 2006).
As previously mentioned, in most of the earlier research executive functioning has been assessed by means of neuropsychological tests. Neuropsychological tests, e.g. the Stroop task, are designed to measure psychological functions, such as executive functioning, that are related to specific neurological structures or pathways. These tests are usually administered in an ideal or experimental setting, such as a quite office, free from distraction. Therefore neuropsychological tests normally give an estimate of a person’s top-performing level of cognitive functioning. Children with impairments of executive functioning however normally struggle with typical everyday situation that demand a certain level of mental organization because of an overload of stimuli. This has been accounted for in this study by the introduction of a screening tool that focuses on the daily routine of a child or an adolescent in order to give a realistic estimate of a child’s cognitive functioning. A questionnaire that addresses parental report
of child’s executive functioning will be administered, in order to investigate executive functioning on a day-to-day behavioural level. The first hypothesis is therefore going to be tested by means of the BRIEF (Behavior Rating Inventory of Executive Function BRIEF; Gioia et al. 2000), a questionnaire assessment tool for executive functions developed for parents and their children. It is expected that children exposed to multiple traumatic experiences will score higher on the BRIEF than children who suffer from PTSD symptoms as a result of a singular traumatic event (Alvarez & Emory, 2006; Teicher et al., 1997; Van Der Kolk, 2006).
It is also interesting to take a further look at the different scales of the BRIEF. By doing this we will not only investigate the executive function in general but will also investigate to what extent children with different types of trauma differ regarding specific executive functions. As previously mentioned it has been shown that people suffering from PTSD usually show impairments of inhibitory control (Weiss, Tull, Viana, Anestis, & Gratz, 2012) and working memory (Vasterling et al., 1998). Nevertheless, it has never been examined within a single study whether singular and multiple traumatised children differ in respect of these specific executive functions by investigating the correspondent subscales of the BRIEF. The second hypothesis is therefore that children suffering from multiple traumas have more impaired inhibitory control and working memory than children suffering from a singular trauma. It is therefore expected on an operational level that the subjects from the multiple trauma group will score higher on the clinical subscales ‘inhibition’ and ‘working memory’ than subjects from singular trauma group. As there are inconsistent finding regarding ‘shifting’ we will investigate in an explorative manner if children exposed to multiple trauma do show more impairment in ‘shifting’ that children who were exposed to a singular trauma.
In addition we will examine on an explorative basis to what extent gender might moderate the relationship between the type of trauma and level of impairments in executive functioning.
Method
Participants and Procedure
The sample group consisted of 30 children and adolescents with an age span of 7 – 17 years and a total mean of 12,3 years (sd= 2.9), out of which 14 were boys and 16 girls. The first group consisted of 11 participants who were exposed to a singular traumatic event (Type 1 Trauma). A validated cut-off score of 30 on the CRIES-13 (Perrin, Meiser-Stedman, & Smith, 2005) was used to select traumatized patients who were admitted to the AMC-de Bascule psychiatric hospital in Amsterdam after a singular traumatic event, such as a car accident or an attack. In Group 1 seven participants were girls and four participants were boys. Unfortunately the mean age of the participants of Group 1 could not be established.
The second group, Group 2, consisted of 19 participants, (10 boys and 9 girls) which were exposed to multiple traumatic events (Type 2 Trauma), such as living in foster care due to dysfunctional family
situations. The Group 2 participants were receiving therapeutic foster care treatment at the Bascule. The treatment applied in therapeutic foster care is the ‘Multidimensional Treatment Foster care’ (MTFC; Fisher & Chamberlain, 2000) which is based on the idea that social behaviour can be best taught through positive reinforcement and that dysfunctional behaviour can best be unlearned by setting limits. The family receives supervision and help by a psychologist in coping with everyday problems. The therapeutic foster care treatment is not expected to improve executive functioning in the children and adolescents (Price et al., 2008). We considered the children and adolescents coming from this kind of therapeutic foster care as multiple traumatized because studies reveal that children who lived in foster care and who received therapeutic foster care support have been exposed to traumatic events during their lifetime and are chronically traumatized (Jonkman et al., 2013).
The study took place at ‘de Bascule’, an academic and psychiatric department of the AMC for developmental disorders in Amsterdam, The Netherlands. All children and adolescents, who were exposed to one or several traumatic events, were enrolled for treatment for either singular or a multiple trauma. Before starting the psychological treatment, printed forms of the BRIEF and the CRIES-13 were sent by post to the caregivers of the children and adolescents. When completed by the caregiver, the forms were sent back to the clinic in order to be analysed.
Measures
Patients of the paediatric and children’s psychiatric clinic Bascule in Amsterdam, with trauma symptoms have been surveyed by means of the CRIES-13 (Children and War Foundation, 2005), when having experienced a singular trauma and the Maltreatment Checklist when having experienced a multiple trauma. The Dutch version of these instruments was used. The reliability of the Dutch version of the CRIES-13 has been validated (Verlinden, van Meijel, Lindauer, & Boer, 2012). The score on the CRIES -13 can be seen as a continuous score. The higher the score, the more the child seems to suffer from post-traumatic stress symptoms. With a total score of 30 or higher, there is an increased risk of posttraumatic stress disorder (PTSD) and further diagnosis and treatment is recommended. Even though not yet validated, clinical practice indicates sufficient face-validity of the Dutch version of the Maltreatment Checklist to assure valid clinical judgments about the severity of trauma symptoms.
In order to examine the relationship between executive functions and trauma in children and adolescents the BRIEF (Behaviour Rating Inventory Executive Functions, Gioia et al., 2000; Nederlandse versie, Huizinga & Smidts, 2010) was administered. There are different versions of the BRIEF, a parent report, a teacher report and a version for the children and adolescents themselves. In this study the parent’s version was used, as parents reports turned out to be particularly reliable and valid when it comes to external behaviour assessment of children and adolescents (Cantwell et al, 1997; Gioia et al., 2000). The BRIEF consists of eight clinical scales (Inhibition, Flexibility, Emotional Control, Initiate, Working Memory, Plan/Organize, Organization of Materials, Monitor) and two validity scales (Inconsistency and Negativity). A representative question out of the BRIEF for parents would be for example on the ‘Working Memory’ subscale: “Is your child easily distracted by sounds, activities and
views?” Higher scores on the BRIEF represent higher impairment of the corresponding scale. A Dutch version in circulation since 2009 has been adopted for the purpose of this study. To date, the BRIEF has not been evaluated by COTAN. The suiting COTAN report is expected to be released by the end of 2013. The BRIEF is suitable for children from 5 to 18 years suffering from psychological, psychiatric or neurological disorders, such as cognitive and emotional disabilities, e.g. ADHD, autism spectrum disorder and PTSD. With a reliability of Cronbach’s alpha > .81 the BRIEF is considered statistically reliable. Due to factor and correlational analysis with other relevant questionnaires the BRIEF is also considered to provide convincing construct, convergent and divergent validity. The convergent and divergent validity of the BRIEF was investigated by using a sample of premature children. In this clinical sample the relationship between the scores on the BRIEF and the scores on the CBCL (Child Behaviour Checklist), the VvGK (Vragenlijst voor Gedragsproblemen bij Kinderen) and the Dutch version of the DISC (Diagnostic Interview Schedule for Children) was determined. The results of these correlational analyses are consistent with expectations. For the purpose of this study the total mean and the means on the subscales of the BRIEF have been contrasted in relation to the two groups.
Results
The data of all 30 participants was used for further analysis. Gender was equally distributed across the conditions χ² (1) = .74, p = .47. For each condition the mean scores of the total score of the BRIEF and its subscales were computed and are presented in Table 1.
Table 1
Mean of total score on BRIEF and subscales with standard deviation (parenthesized) for the singular trauma and multiple trauma condition
Trauma Total score Inhibition Working Memory Flexibility
Singular trauma
(Type 1) 126 (21.9) 15.8 (3.5) 17.3 (4.3) 13.3 (2.9)
Multiple trauma
(Type 2) 138 (32.8) 17.8 (5.4) 19.3 (5.8) 13.7 (4.4)
In order to check for a significant difference between these means four separate analysis of variances (ANOVA) were conducted. Since the data was normally distributed and the groups were independent from each other the homogeneity of variances can be considered to have been achieved in accordance with the respective ANOVA assumptions. The one-way ANOVAs were conducted to compare the effects of trauma types on the score of general executive functions (within subject) in the singular and multiple trauma conditions (between-subject) and the effects of trauma types on the subscales ‘Inhibition’, ‘Working memory’ and ‘Flexibility’.
First, an ANOVA with the type of trauma as an independent variable and the total score on the BRIEF as the dependent variable was conducted. No statistically significant effect of type of trauma on the total BRIEF score was found, F (1,28) = 1.01, p > .05. That means, participants of the Type 1 group did not score significantly different from participants of the Type 2 group on the total BRIEF.
Another one-way ANOVA was conducted to compare the effects of type of trauma on the score of ‘Inhibition’ (within subject) in the singular and multiple trauma conditions (between-subject). The type of trauma was again used as an independent variable and the score on the ‘inhibition’ subscale was used as the dependent variable. No statistically significant effect of type of trauma on the subscale ‘inhibition was found, F (1,28) = 1.21, p > .05. Participants of the Type 1 trauma group did therefore not score significantly different from participants of the Type 2 trauma group on the ‘inhibition’ subscale.
Furthermore another one-way ANOVA was conducted to compare the effects of type of trauma on the score of ‘working memory’ (within subject) in the singular and multiple trauma conditions (between-subject). The type of trauma was again used as an independent variable and the score on the ‘working memory’ subscale was used as the dependent variable. No statistically significant effect of the type of trauma in the subscale ‘working memory’ was found, F (1,28) = 1.04, p > .05. That means, participants of the Type 1 trauma group did not score significantly different from participants of the Type 2 trauma group on the ‘working memory’ subscale.
Another one-way ANOVA was conducted to compare the effects of type of trauma on the score of the subscale ‘flexibility’ (within subject) in the singular and multiple trauma conditions (between-subject). The type of trauma was again used as an independent variable and the score on the ‘flexibility’ subscale was used as the dependent variable. No statistically significant effect of the type of trauma on the subscale ‘flexibility’ was found, F (1,28) = .08, p > .05. Participates of the Type 1 trauma group did not score significantly different from participants of the Type 2 trauma group on the ‘flexibility’ subscale.
In order to look for a gender effect in an explorative manner, a factorial ANOVA was conducted. Results showed that there were no gender effects across the condition on the total scale of the BRIEF, F =(1,26) = 3.7, p= .06. Also, there were no gender effects found on the subscale ‘Inhibition’ (F =(1,26) = 2.8, p > .05.), nor on the subscale ‘Working Memory’ (F =(1,26) = 4.0, p= .06), nor on the subscale‘
(F =(1,26) = 2.8, p > .05.) Discussion
The aim of this study was to examine to what extent executive functioning of children with either a singular or multiple trauma differ. In addition, the way in which the impairments of the concrete executive functions inhibition, working memory and flexibility differ in children, with either a singular or multiple trauma, was investigated. It revealed that children suffering from multiple trauma have more impaired general executive functions than children suffering from singular trauma. Furthermore, multiple traumatized children have more impaired inhibition, working memory and flexibility than children who
experienced only one traumatizing event. However, these differences between multiple and singular traumatized children were not statistically significant. These results were not according to the expectation and therefore, the hypothesis that children suffering from a multiple trauma have more impaired general executive function, inhibitory control, working memory and flexibility than children suffering from singular trauma must be rejected.
Furthermore, it revealed out that gender does not moderate the relationship between type op trauma and executive functioning. Whether it is a boy or a girl who suffers from either singular or multiple traumas does not appear to affect the impairments in executive functioning.
So far, to the best of my knowledge, there has been little research done on executive functioning of singular and multiple traumatized children. Due to lack of possibilities to contrast the results of the current study with previously carried out similar studies, the hypotheses of the current study are based on related, though differently designed, earlier studies: The only study in which different trauma groups where compared is the study undertaken by De Prince et al. (2009), which investigated the executive functioning of children who suffered from a familial trauma relative to non-familial and no trauma exposure. Here, they found that familial trauma was associated with poorer performance on an executive function than non-familial and no trauma. The format of De Prince et al. (2009) study is comparable in terms of the sample characteristics: In the current study the children from the multiple trauma group, who were retrieved from the therapeutic foster were all traumatized by familial problems. Even though the participants of the multiple trauma condition scored higher on the BRIEF than participants of the singular trauma condition, when compared to the results of De Prince et al. (2009), no statistically significant effect of type of trauma on the general executive function and inhibition, working memory and flexibility could be determined. A possible reason for this could be the difference in the assessment of executive functions. Whereas in the current study a questionnaire was used, De Prince et al. (2009) used neuropsychological tests in order to measure executive functioning. The advantage of a screening tool, such as the BRIEF is that it can provide an insight into possible executive dysfunction and how it is embedded in the child’s everyday behaviour associated with specific domains of the executive functions. Neuropsychological test procedures are standardized test methods in a clinical setting for cognitive performance. It is probable that traumatized children develop various coping strategies in their everyday routine that might help them to be functional and goal oriented in their everyday life (Chan, Shum, Toulopoulou, & Chen, 2008). Perhaps these difficulties could be revealed only in a clinical setting and not by questionnaires on everyday behavioural patterns. Thus, the contrary finding of the Prince et al. (2009) and of the current study might be explained by the difference in the method of assessment: The objective clinical evaluation of primal executive functioning as opposed to the demonstration of adjusted executive functioning in everyday life.. As presented in Vasterling et al. (1998) participants suffering from PTSD show significant impairments in inhibitory control and working memory compared to participants who did not suffer from PTSD. Although not significant in statistical terms, the results of the current study indicate that there is a slight difference in general executive functioning, inhibitory control and flexibility between singular and multiple
traumatized children. However, supposing that there was a significant differentiation found, the format of the current study and also that of Vasterlings et al. (1998) study would not have been able to entirely explain whether trauma is primarily linked with limited working memory span and limited inhibitory control. Likewise, impairments of working memory may be present due to problems with inhibiting ‘distracters’ such as internal or external stimuli during the tasks. Auperle et al. (Aupperle, Melrose, Stein, & Paulus, 2012) point out that the aforesaid reported relationship between trauma and interrupted memory recall might reflect the difficulty inhibiting related, but irrelevant stimuli. For example, a physically maltreated child may not be able to suppress detecting trauma related stimulus such as a walking stick. That in turn, might interrupt the child’s working memory span. Vasterling et al. (1998) discovered an interesting trend in this regard: Intruding information, which cannot be inhibited across various cognitive tasks was related to the gravity of typical trauma symptoms, such as hyperarousal and flashbacks regarding the traumatic event. For a summary of the different theoretical approaches, refer to the graphic representations provided below.
Figure 1. Theoretical approaches of causal relationship between trauma and executive functions
In 2013, the new Diagnostic and Statistical Manual of Mental
Disorders, 5th Edition (DSM-5), i.e. the revised version of the DSM-IV-TR (2000), was published by the American Psychiatric Association (APA). A number of changes
Trauma IC WM Trauma IC WM Trauma IC WM 1. Trauma affects or is affected by both working memory and inhibitory control. (Vasterling et al., 1998)
2.Traumasymtopms are related to Impairments in working memory due to problem with inhibiting irrelevant stimuli. Auperle et al. (2012)
3. Trauma is related to impaired working memory and inhibitory control, which are again mutually affecting each other.
were implemented, especially regarding the diagnostic criteria’s of PTSD. In the DSM-IV-TR, PTSD was categorised under Anxiety Disorders, whereas now it falls under, Trauma- and Stressor-Related Disorders. In the DSM-IV-TR a traumatic event was defined as an experience that involves threatened death or severe injury to an individual or witnessing an individual experience threatened death or severe injury (Criterion A1) and its was also specified that an individual’s respond to that event involves intense fear, helplessness, or horror (Criterion A2). Compared to the DSM-IV-TR the DSM 5 is more explicit as to what defines a traumatic event. With regard to changes in the DSM 5 the APA states, that “sexual assault is specifically included, as is a recurring exposure that could apply to police officers or first responders.”(APA Division of Research, 2013) Moreover, research precedent to the release of the DSM 5 proposed that the type of stressor does not seem to affect the onset and severity of PTSD (Friedman, Resick, Bryant & Brewin, 2011). It was therefore proposed that the idea of a substantial difference with respect to either a one-time or prolonged trauma and development of PTSD should be reconsidered. As a consequent the APA decided to dispose the Criteria A2 stating that “Language stipulating an individual’s response to the event—intense fear, helplessness or horror, according to DSM-IV—has been deleted because that criterion proved to have no utility in predicting the onset of PTSD.”(APA Division of Research, 2013). The results of the current study align with these new theories about different types of trauma stressor. The notion that there is in fact no difference between singular and multiple trauma on variables such as executive functions could then explain the lower predictive value of the types of trauma concerning the onset and development of PTSD.
Limitations
This study was primarily limited by its small sample size. The completed questionnaires were mainly taken from the electronic medical record (Care 4) used by the Bascule at the AMC Amsterdam. More contact between the researcher and the target group, such as personally contacting patients and a joint completion of questionnaires, may have led to increased participation and therefore a bigger sample size. Also, the group sizes were not entirely equally balanced as more children suffering from a multiple trauma than children suffering from a singular trauma were included. An earlier commencement of data collection would have enabled a greater number of participants who experienced a one-time traumatic event.
Future research and clinical implications
In order to operationalize executive function the questionnaire BRIEF was used. Isquith et al. (2008) state the following about the BRIEF: “The clinical information gathered from an in-depth profile analysis is best understood, however, within the context of a full assessment that includes (a) a detailed history of the child and the family, (b) performance-based testing, and (c) observations of the child’s behaviour. A thorough understanding of the BRIEF, including its development and its psychometric properties, is a prerequisite to interpretation.” In this study, however, the scores on the BRIEF where taken in isolation to judge executive functioning. Future research should therefore focus on a holistic
approach regarding the assessment of executive functioning. A greater depth of information could be obtained with the inclusion of neuropsychological tests, such as ‘Stroop Task’ or personal interviews for both trauma groups.
In addition, it is suggested that future research should incorporate a third group of children that were not traumatized at all to serve as a control group. By including a control group, alternative explanations for the results could be easier filtered. Also, investigating whether there is a significant difference between the two trauma groups and the non- trauma group would assist in the determination of the effectiveness of operationalization and measurement of ‘executive functioning’. Based on the psychometric information that can be extracted from the BRIEF, we know that the standard mean total score of children from a normal population is 124 (sd =25). This mean-value lies 10 scores below the total mean score of the current study (134; sd= 29), which implies that the children who took part in this study had indeed more impaired executive functions that children from the normal population. However, in order to see to what extent the children differ significantly on the BRIEF a non-trauma group has to be included into the actual data set upon which all statistical analyses are based.
Future research should also focus on the causal relationships of different executive functions and trauma symptoms. The results indicate that there might be a causal relationship between the different executive functions, such as inhibition and working memory and the severity and types of trauma symptoms. By understanding the underlying neuropsychological mechanisms of trauma symptoms, therapeutic care could be more effectively applied, for example by training certain executive functioning such as working memory and inhibition. This might in turn alleviate distressful trauma symptoms in order to sooth hyperarousal and flashbacks regarding trauma-related stimuli (Vasterling et al., 1998). More experimental research in this field is therefore necessary to support children who suffer from either singular or multiple trauma in an individualized manner.
Taken together, this study highlights the need to pay detailed attention to the differences in assessment of executive functioning and trauma. In order to be able to apply the above-mentioned support, based on training executive functions, the obtainment of a distinct and comprehensive picture of individual impairments and deficiencies is necessary. In clinical practice this can only be achieved by a multidimensional approach and use of several different assessment tools, such as questionnaires, personal interviews and neuropsychological testing.
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