Examination of outcome after mild traumatic brain injury

Neuropsychological Rehabilitation, 2013 Vol. 23, No. 3, 333–362, http://dx.doi.org/10.1080/09658211.2012.758419

Examination of outcome after mild traumatic brain injury: The contribution of injury beliefs and Leventhal’s Common Sense Model Deborah L. Snell1,4, E. Jean C. Hay-Smith1, Lois J. Surgenor2, and Richard J. Siegert3 1

Rehabilitation Teaching and Research Unit, University of Otago, Wellington, New Zealand 2 Department of Psychological Medicine, University of Otago, Christchurch, New Zealand 3 School of Public Health and Psychosocial Studies and School of Rehabilitation and Occupation Studies, AUT University, Auckland, New Zealand 4 Concussion Clinic, Brain Injury Rehabilitation Service, Burwood Hospital, Canterbury District Health Board, Christchurch, New Zealand

Associations between components of Leventhal’s common sense model of health behaviour (injury beliefs, coping, distress) and outcome after mild traumatic brain injury (MTBI) were examined. Participants (n ¼ 147) were recruited within three months following MTBI and assessed six months later, completing study questionnaires at both visits (Illness Perceptions Questionnaire Revised, Brief COPE, Hospital Anxiety and Depression Scale). Outcome measures included the Rivermead Post-Concussion Symptoms Questionnaire and Rivermead Head Injury Follow-Up Questionnaire. Univariate and multivariate (logistic regression) analyses examined associations between injury beliefs, coping and distress at baseline, and later outcome. Participants endorsing stronger injury identity beliefs (p , .01), expectations of lasting severe consequences (p , .01), and distress (p , .01) at time one, had greater odds of Correspondence should be addressed to Dr. Deborah L. Snell, Brain Injury Rehabilitation Service, Burwood Hospital, Private Bag 4708, Christchurch, New Zealand. Email: [email protected] This research has been support by a Small Project Grant from the Neurological Foundation of New Zealand (Grant no: 0728-SPG). # 2013 Taylor & Francis

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SNELL, HAY-SMITH, SURGENOR, AND SIEGERT

poor outcome at time two. Coping styles were also associated with later outcome although variability in findings limited interpretability. Associations between psychological variables and outcome were examined and 76.5% of cases were correctly classified by the model. Consistent with Leventhal’s model, participant beliefs about their injury and recovery had significant associations with outcome over time. Coping also appeared to have important associations with outcome but more research is required to examine these. Current reassurance-based interventions may be improved by targeting variables such as injury beliefs, coping and adjustment soon after injury. Keywords: Mild traumatic brain injury; Illness perceptions; Outcome.

INTRODUCTION Mild traumatic brain injury (MTBI) is a significant public health concern. Available evidence suggests that up to 600 cases per 100,000 people aged 15 and over are likely to sustain a MTBI each year (Cassidy, Carroll, Peloso, Borg, von Holst et al., 2004; NZGG, 2006). While substantial recovery is expected to occur within the first three months (McCrae, Iverson, McAllister, Hammeke, Powell et al., 2009), up to 15% of cases may not have recovered more than a year after injury (Iverson, 2005; Ponsford, 2005). This group, often referred to as suffering from the post-concussion syndrome (PCS), typically presents with complex and clinically challenging symptoms with associated psychosocial burden (Wood, 2004). Identifying predictive factors for slow recovery extending beyond the three month threshold is of clinical importance. This information will facilitate earlier identification of both at risk cases and provide treatment targets to reduce risk for poor outcome. Most available explanatory models of slow MTBI recovery describe interactions between various demographic and clinical factors (Kay, Newman, Cavallo, Ezrachi & Resnick, 1992; Wood, 2004; Rose, 2005) but there is debate regarding the relative importance of these factors in explaining the development of PCS. In particular, variables such as injury mechanism and severity have been consistently shown to have little association with outcome (Carroll, Cassidy, Peloso, Borg, von Holst et al., 2004). While it is suggested that persisting symptoms after MTBI may be mediated by psychological mechanisms such as anxiety, depression, symptom expectation and misattribution (Mittenberg, DiGuilio, Perrin & Bass, 1992; Suhr & Gunstad, 2005; McCrea et al., 2009; Panayiotou, Jackson & Crowe, 2010; Lange, Iverson & Rose, 2011), there is limited high quality research systematically examining these. The idea that there is a psychological component to the expression of certain physical diseases is not new (Macleod, 2010) and

MTBI OUTCOME: ASSOCIATIONS WITH INJURY BELIEFS AND COPING

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MTBI recovery models typically place psychological factors in a key mediating position. However, the limited empirical evidence supporting such hypothesised associations with outcome is problematic for these recovery models. Examining psychological constructs known to help explain recovery trajectories in other health conditions may provide better understanding about the slow to recover MTBI group. For example, understanding how individuals perceive and cope with their injury could have important implications for detecting and managing those at risk. One of the more influential illness perception models is Leventhal’s common sense model of health and illness behaviour (CSM: Leventhal, Leventhal & Contrada, 1998; Leventhal, Leventhal & Cameron, 2001). The CSM is a theoretically derived model proposing that patients construct their own representations of their health condition that helps them make sense of their experience and provides a basis for coping. The model describes parallel cognitive and emotional processes that interact in the way an individual copes with and adjusts to their illness experience such that a health threat generates both a cognitive representation of the threat and a corresponding need for procedures to manage the danger (i.e., danger control), and emotional states of fear and distress and a corresponding need for procedures to manage these (i.e., fear control). Based on qualitative studies, Leventhal et al. have identified five core components of illness representations and these are identity (illness label and associated symptoms), expected consequences, timeline perceptions, perceptions of controllability, and causal attributions. The CSM has been helpful in understanding health outcomes in a range of conditions including cardiovascular disease (French, Cooper & Weinman, 2006), chronic fatigue syndrome (Petrie, Moss-Morris & Weinman, 1995), fibromyalgia (van Ittersum, van Wilgen, Hilberdink, Groothoff & van der Schanns, 2009), chronic pain (Foster, Bishop, Thomas, Main, Horne et al., 2008), and cancer (Llewellyn, McGurk & Weinman, 2007; Foster et al., 2008). We are aware of only one study that has considered the applicability of CSM components to understanding outcome after MTBI (Whittaker, Kemp & House, 2007). This showed that patients with stronger beliefs about the seriousness and enduring nature of injury consequences were at increased risk for developing PCS three months after injury. However this study only examined one aspect of the CSM, namely illness perceptions. Other components of the model such as coping responses were not examined. The development of effective health interventions should be directed by theory so that mechanisms underlying change can be better understood (Leventhal, Weinman & Phillips, 2008). In this regard the science of rehabilitation in general has been criticised for the lack of attention to development of theoretical models (Siegert, McPherson & Dean, 2005). Application of a model of health behaviour such as the CSM to MTBI may provide a coherent theoretical framework within which person-specific treatments for MTBI

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could be developed based on an individual’s injury and recovery perceptions, and their emotional and coping responses to the injury. Recent systematic reviews of the effectiveness of treatments for MTBI support educational, reassurance and guidance models of intervention when these interventions are provided early following injury (Borg et al., 2004; Comper, Bisschop, Carnide & Triccio, 2005; Snell, Surgenor, Hay-Smith & Siegert, 2009). Typically these educational interventions include information about recovery timeframes and expected symptoms, strategies for managing symptoms, support to gradually increase levels of activity and resume usual levels of participation such as employment (Borg et al., 2004; Ruff, 2005; McCrea et al., 2009). More carefully tailoring intervention on the basis of better understanding of the individual’s perceptions of and responses to their injury may enhance the potency of the intervention. However, before such interventions can be refined greater understanding of hypothesised interactions between the various demographic and clinical factors, and outcome after MTBI, is needed.

Study aim and hypotheses Noting the above issues, this study examined the demographic and clinical characteristics associated with good and poor outcomes in an MTBI sample recruited within three months following injury. Specifically, the study explored the extent to which components of the CSM were associated with MTBI outcomes over time. The following a priori hypotheses were examined: (1) Patterns of injury perceptions, coping and distress (i.e., core components of Leventhal’s CSM) within three months of injury (time one) will be associated with different clinical outcomes six to nine months (time two) following a MTBI. (2) Changes in (i) injury perceptions, (ii) coping, and (iii) distress (i.e., core components of Leventhal’s CSM) will be associated with changes in clinical outcome between time one and time two (e.g., change from poor outcome at time one to good outcome at time two; change from good outcome at time one to poor outcome at time two).

METHOD Design and setting A prospective study with repeated measures was conducted in order to examine recovery trajectories after MTBI. Participants were recruited from two sites in Christchurch, New Zealand: a large public hospital emergency


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department (ED) and a hospital-based outpatient concussion clinic (CC) which accepts referrals from the ED and community healthcare providers. Between February 2008 and July 2009, consecutively attending patients were approached, and successfully recruited participants completed a battery of questionnaires at recruitment and six months later.

Participants Eligible participants were those that had sustained an MTBI within the preceding three months; were aged 16 or older; with no previous history of severe traumatic brain injury or significant comorbid health conditions such as cardiovascular disease or neurological disorder. Cases were excluded if there had been significant additional injuries sustained in the same accident which might make it difficult for participants to discriminate between their various injury symptoms. Broad inclusion and exclusion criteria were used in an effort to ensure that the study sample was clinically representative. The definition of MTBI was that recommended by the New Zealand Guidelines Group (NZGG, 2006) which is based on that proposed by the WHO Collaborating Centre Task Force (Carroll, Cassidy, Holm, Kraus & Coronado, 2004a), and is as follows: “MTBI is an acute brain injury resulting from mechanical energy to the head from external physical forces. Operational criteria for clinical identification include one or more of the following: 1. 2. 3. 4.

Confusion or disorientation. Loss of consciousness (LOC) (for 30 minutes or less). Post-traumatic amnesia (PTA) (less than 24 hours). Other transient neurological abnormalities such as focal neurological signs, seizure and intracranial lesion not requiring surgery. 5. The Glasgow Coma Scale (GCS) (Teasdale & Jennett 1974) score should be 13 or greater, 30 minutes after injury (or later upon presentation for healthcare). In addition these manifestations of MTBI must not be due to drugs, alcohol, medications, caused by other injuries (e.g., systemic injuries, facial injuries, or intubation), caused by other problems (e.g., psychological trauma, language barrier, co-existing medical conditions) or caused by penetrating cranio-cerebral injury” (NZGG 2006, p 22). The above diagnostic criteria were applied by reviewing information in the clinical record and from participant report. However it was anticipated that on occasion all relevant acute injury marker information might not be available (such as GCS score). In this situation the potential participant was eligible for study inclusion if the case history and injury mechanism were considered

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consistent with MTBI, and/or other aspects of the diagnostic criteria could be verified. In most cases, durations of LOC and PTA were estimated retrospectively based on participant self-report. Where possible, remarks in the hospital record and/or witness reports regarding LOC or amnesia were taken into account. Because the estimation of PTA can be unreliable, particularly when this estimate is made retrospectively (King, Crawford, Wenden, Moss & Wade, 1997), participants were not included if retrospectively reported PTA was the only criterion used for determining MTBI.

Measures The Illness Perception Questionnaire –Revised. (IPQ-R; Moss-Morris, Weinman, Petrie, Horne, Cameron et al., 2002). The IPQ-R provides a quantitative assessment of illness representations in Leventhal’s CSM. First, the Identity Scale lists 14 symptoms common to many illnesses, requiring the respondent to endorse symptoms they believe are attributable to their illness. Second, the Beliefs Scale consists of 38 items assessing beliefs about perceived illness duration and course, illness consequences, perceived control (by personal actions and by treatment), illness coherence (degree to which the illness can be understood), and emotional reactions to the illness. The third and final scale assesses causal attributions (Causal Attributions Scale) and includes 18 possible illness causes. The Beliefs Scale and the Causal Attributions Scale ask the respondent to rate their agreement with statements about symptom beliefs and cause on a five point Likert scale from “strongly disagree”, to “strongly agree”. For this study the IPQ-R was modified for MTBI by changing the word “illness” to “head injury”. Four additional symptoms (memory problems, concentration problems, irritability, and balance problems) were added to the original 14 Identity Scale items to ensure that most symptoms commonly reported after MTBI were included (McCrae et al., 2009). Other common symptoms after MTBI, such as fatigue, headaches, dizziness, and sleep problems, were already included in the original IPQ-R Identity Scale. Recent factor analysis of the IPQ-R modified for MTBI (Snell, Siegert, Hay-Smith & Surgenor, 2010) suggests this is generally an acceptable measure of the key components of injury perceptions after MTBI. However, the factor analysis recommended that minor refinement of the IPQ-R Causal Scale is required before this is used confidently with MTBI samples and so the causal scale results were not analysed in the present study. The Brief COPE. (Carver 1997). This is a modified and shortened version of the 60 item COPE Inventory developed by Carver and colleagues (Carver, Scheier & Weintraub, 1989) to assess different coping strategies. Responses


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were scored on a four point Likert scale ranging from “I usually don’t do this at all” through to “I usually do this a lot”. Scores for each subscale range from two to eight, with higher scores indicating more frequent use of the specified coping strategy. The Brief COPE forms 14 two-item subscales and factor analysis has suggested three dimension scores can also be derived (Snell, Siegert, Hay-Smith & Surgenor, 2010) involving approach, avoidance, and social coping styles. The Hospital Anxiety and Depression Scale. (HADS; Zigmond & Snaith 1983). The HADS has utility as a measure of anxiety, depression and psychological distress following TBI (NZGG, 2006; Whelan-Goodinson, Ponsford & Scho¨nberger, 2009). Seven items measure anxiety symptoms and a further seven measure depressive symptoms with each item rated on a four point scale, ranging from zero to three. The seven items in each subscale are summed and total scores for each subscale range from 0 to 21, characterised as normal (0–7), mild (8 –10), moderate (11–14) or severe (15–21).

Outcome Measures The Rivermead Postconcussion Symptoms Questionnaire. (RPQ; King, Crawford, Wenden, Moss & Wade, 1995). This self-report symptom inventory comprises 16 common symptoms following MTBI. Participants were requested to rate the presence and problem status of post-concussional symptoms on a scale of zero to four (0 ¼ not experienced at all; 1 ¼ no more of a problem than before the injury; 2 ¼ a mild problem; 3 ¼ a moderate problem; 4 ¼ a severe problem). RPQ scores were determined in two ways. First a total score, being the sum of all item scores greater than or equal to two, was calculated. Second, three factors (somatic, cognitive, and emotional) can be derived from the RPQ (Potter, Leigh, Wade & Fleminger, 2006; Herrmann, Rapoport, Rajaram, Chan, Kiss et al., 2009) and these three domain scores were also calculated. Somatic symptoms were headaches, feelings of dizziness, nausea and vomiting, noise sensitivity, sleep disturbance, light sensitivity, and double vision. Cognitive symptoms were forgetfulness/poor memory, poor concentration, and taking longer to think. Emotional symptoms were being irritable/easily angered, feeling depressed or tearful, feeling frustrated or impatient. The Rivermead Head Injury Follow Up Questionnaire. (RHIFUQ; Crawford, Wenden & Wade, 1996). This questionnaire measures functional and social outcomes following traumatic brain injury (TBI). Perceived injuryrelated change is rated on 10 items of everyday activities and aspects of participation such as work, leisure and social interaction. Participants were asked

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to rate change compared with before their injury (0 ¼ no change; 1 ¼ no change, but more difficult; 2 ¼ a mild change; 3 ¼ a moderate change; 4 ¼ a very marked change). Total RHIFUQ score was calculated by summing item scores.

Outcome Outcome was defined dichotomously (good/poor) following previous research in the area (Whittaker et al., 2007; Kashluba, Paniak & Casey, 2008; Stulemeijer, van der Werf, Borm & Voc, 2008; Heitger, Jones, Macleod, Snell, Framptom et al., 2009). Poor outcome required the following: 1. Meets criteria for PCS (ICD-10 criteria), operationally defined as a score of two or more on any symptom within each of the three RPQ domains as described above (cognitive, emotional, somatic), and 2. Notable problems with activities and participation using RHIFUQ. There is no systematic research available to guide use of the RHIFUQ so for this study we used the criterion defined by Heitger et al. (Heitger et al. 2009), of total RHIFUQ score of 8 or higher, with a score of 2 or higher on at least one item, and 3. Negative change in work status since the injury, that is, yes to either “I am still off work or study because of my injury” or “I am back at work or study but on reduced hours”. Participants not meeting all three criteria were categorised as having a good outcome. For participants who were not working at the time of injury, outcome was determined on the basis of the first two criteria alone.

Data collection Following a formal recruitment and consent process, all participants completed study questionnaires either face-to-face with the principal investigator, or by telephone interview or mail, depending on the preference of the participant. Ethical approval for the project was obtained from the local research ethics committee. Demographic, injury and medical information was collected by file review and responses from questions included in the study questionnaire booklets. Variables included the following: age; gender; ethnicity; highest educational qualification; employment and compensation problems; injury severity indicators such as GCS score, duration of post-traumatic amnesia, and imaging results (MRI/CT) if available; any other injuries sustained concurrently with MTBI; history of treatment for a psychiatric condition and/or comorbid psychiatric diagnosis; substance use; and medical history. Information regarding compensation status was collected given consistent findings in the literature


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that this is important in understanding MTBI outcome (Carroll et al., 2004). All participants in this study qualified for cover by the “no-fault” governmentfunded injury insurance scheme (Accident Compensation Corporation). This cover included treatment costs and if the participant was in employment at the time of their injury, financial compensation until returning to employment.

Data analysis Data were analysed using SPSS v16.0 for Windows. All demographic (except age), site and injury severity indicators (e.g., loss of consciousness, GCS, PTA, injury cause) were coded as categorical variables. Continuous variables included age, days post-injury and all study psychological measures. Hazardous use of alcohol was treated as a categorical variable coded dichotomously (no/yes), and determined using a method similar to that described by Meares et al. (Meares, Shores, Batchelor, Baguley, Chapman et al., 2006). This was based on the frequency and intensity of drinking behaviour. A hazardous level of drinking was defined as consuming alcohol two to three times a week or more and consuming six standard drinks or more on a usual day of drinking. Most participants provided full data sets and because the amount of missing data was minimal the principle approach to managing missing data was listwise deletion, the default procedure of SPSS. Descriptive statistics and univariate statistical tests (Chi-square tests, independent samples t-tests, paired samples t-tests) were used to describe the demographic, health and psychometric features of participants and assess the relationships between demographic, clinical and psychological measures, and outcome. Recruitment site was treated as a grouping variable to check for differences between cases referred from the ED and the CC. Injury perception scores (IPQ-R) were further examined using a distribution-based approach similar to that described by Foster et al. (2008). Accordingly, IPQ-R subscale/dimension scores were categorised as above or below the median based on the distribution of scores in the sample. The relationships between time 1 IPQ-R scores (i.e., potentially helpful and unhelpful perceptions for each subscale/dimension) and clinical outcomes at time 2 were then examined. Finally, mean changes in scores across psychological measures between time 1 and 2 were calculated and examined using paired samples t-tests to identify which measures demonstrated changes. Next, mean change scores were examined according to clinical outcome at time 2 using a series of independent samples t-tests. For the logistic regression analyses, outcome at study follow-up was dichotomously defined (good/poor) as described. Univariate tests (Chisquare and independent sample t-tests) identified the extent to which time 1 independent variables within each variable cluster (pre-, peri-, and postinjury variable clusters) were associated with the dependent variable

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(outcome at time 2). Statistically significant variables (p ≤ 0.1) from each cluster were retained. A series of multivariate analyses (binary logistic regression) then assessed the extent to which the resultant significant baseline independent variables were associated with time 2 outcome. Data are reported as odds ratio (OR), 95% confidence intervals (CI). Effect sizes were calculated for significant results using Cohen’s interpretation rules (Munro, 2005). Given the number of anticipated statistical analyses a more conservative alpha level was applied to reduce risk of Type I error and so a 2-tailed p , .01 was used to evaluate statistical significance.

RESULTS Description of study sample In total 147 people sustaining an MTBI within the preceding three months were recruited into the study. During the period of recruitment there were 207 people who met study inclusion and exclusion criteria but either could not be contacted (n ¼ 163) or declined to take part (n ¼ 44). This nonrecruited group differed from the recruited sample in that it was younger (MD 12.3, 95% CI 9.3–15.2, p , .01) and more likely to be male (OR 2.4, 95% CI 1.6–3.6, p , .01). Of the 147 people recruited into the study, 125 completed both study visits, representing a loss to follow up of 15.0%. Table 1 shows the characteristics of participants completing both study visits compared with those only completing at time 1, across demographic and clinical variables. As shown, the groups only differed significantly on age, with the group not completing at time 2 being younger on average than the group completing both study visits (Mean difference 11.7, 95% CI 4.7– 18.6, p , .01). At recruitment, mean age of participants was 43.6 years (SD ¼ 15.8), with slightly more women than men. In keeping with the ethnic make-up of the wider population in this setting, the majority of the sample identified as New Zealand European. Of the participants who self-reported past treatment for a psychiatric illness (n ¼ 44), the majority reported this was for depression (84%). The most commonly reported comorbid psychiatric diagnosis was depression (n ¼ 19) and two participants reported comorbid post-traumatic stress disorder. Injury severity markers were as expected with most demonstrating a GCS score of 15 on first presentation to healthcare services, LOC less than one minute or not at all, and PTA estimated as less than one hour. The most common cause of injury was falls. Two people self-reported a PTA of more than 24 hours but were included because there was no objective information to support the PTA estimate and examination of all other injury variables clearly supported a diagnosis of MTBI. The known variability in reliability of self-reported PTA was discussed earlier.


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TABLE 1 Demographic and clinical variables by study completion

Variable

Completed both visits (n ¼ 125) N (%)1

Demographic characteristics Age in years M (SD)1 43.6 (15.8) Gender (male) 53 (42.4) Ethnicity - New Zealand European 107 (85.6) - New Zealand Maori 5 (4.0) - Other 13 (10.4) Educational qualifications - None 24 (19.2) - High school and polytech 75 (60.0) - Tertiary 26 (20.8) Work status at time of injury - Employed full-time 70 (56.0) - Employed part-time 19 (15.2) - Studying 13 (10.4) - Not employed 16 (12.8) - Other 7 (5.6) Clinical characteristics Injury type - Motor vehicle accident 14 (11.2) - Road traffic accident 10 (8.0) - Falls 51 (40.8) - Assault 7 (5.6) - Sports related 23 (18.4) - Other 20 (16.0) Glasgow Coma Scale Score (n ¼ 122) - 15 98 (80.3) - 14 17 (13.9) - 13 7 (5.8) Loss of consciousness - None 31 (24.8) - ≤ 1 minute 49 (39.2) - . 1 minute ≤ 5 minutes 25 (20.0) - . 5 minute , 30 minutes 20 (16.0) Post-traumatic amnesia - None 45 (36.0) - ≤ 1 hour 50 (40.0) - . 1 hour ≤ 24 hours 27 (21.6) - . 24 hours 2 (1.6) Comorbid psychiatric 21 (16.8) diagnosis

Only completed time 1 (n ¼ 22) N (%)1

31.9 (10.8) 12 (54.5)

Mean difference/ odds ratio (95% Confidence Interval)2

MD 11.7 (4.7, 18.6) OR 1.6 (0.7, 4.1)

p-value .0013 .2904 .0714

17 (77.3) 4 (18.2) 1 (4.5) .7244 5 (22.7) 14 (63.6) 3 (13.6) .4594 10 (45.5) 2 (9.1) 5 (22.7) 4 (18.2) 1 (4.5) .5564 4 1 6 3 5 3

(18.2) (4.5) (27.3) (13.6) (22.7) (13.6) (n ¼ 21) 21 (100) 0 0

.0844

.3944 3 (13.6) 10 (45.5) 7 (31.8) 2 (9.1) .2944 4 (18.2) 13 (59.1) 5 (22.7) 0 6 (27.3)

OR 0.5 (0.2, 1.5)

.2424

(Continued)

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Table 1. Continued.

Variable Pre-injury psychiatric history Previous MTBI Compensation problems Recruitment Site CC ED

Only completed time 1 (n ¼ 22) N (%)1

Mean difference/ odds ratio (95% Confidence Interval)2

p-value

44 (35.2)

6 (27.3)

OR 1.5 (0.5, 4.0)

.4544

31 (24.8) 6 (4.8)

10 (45.5) N/A5

OR 0.4 (0.2, 1.0)

.0464

74 (59.2) 51 (40.8)

12 (54.5) 10 (45.5)

OR 0.8 (0.3, 2.1)

.6834

Completed both visits (n ¼ 125) N (%)1

1∗ M (SD) where indicated. 2MD and OR reported if able to be calculated. 3Independent samples ttest. 4Chi-square test. 5N/A ¼ data not available.

Return to work and treatment information was collected from participants who attended at time 2. Analysis of this information indicated that 28 (22.4%) reported they were still off work or on reduced hours. Seventy participants (56.0%) reported that they had returned to usual work hours or study. The remaining 27 participants reported that they had not been working at the time of injury and indicated that there had been no change in their work status. Analysis of treatment information indicated that 48 participants (38.7%) reported they did not participate in any treatment following their injury. It is not known whether or not any treatment was offered to these participants. One participant did not complete the treatment questions. Of the 76 participants indicating they had treatment after their MTBI, 30 (24.2%) said they had occupational therapy; 49 (39.5%) reported they had physiotherapy; 28 (22.6%) said they were prescribed medication for MTBI symptoms; 15 (12.1%) said they had psychology sessions (counselling, saw a clinical psychologist); and 20 (16.1%) said they had help returning to work. Forty four participants (35.5%) reported having participated in more than one treatment. As might be expected, participants in the poor outcome group had greater odds of having had treatment after their injury (OR 4.2, 95% CI 1.5–12.0, p , .01). The demographic and clinical characteristics of the study sample at recruitment are described in greater detail elsewhere (Snell, Siegert, Hay-Smith & Surgenor, 2011a) and appear similar to those reported in other recent New Zealand MTBI studies (Snell & Surgenor, 2006; Heitger et al., 2009).

Cases meeting criteria for poor outcome at time 2 At an average of 7.4 months following injury (mean days post injury ¼ 222.4, SD 24.7; range 188–270), 31 participants (24.8%) met criteria for a poor


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outcome. The odds of poor outcome at time 2 were not significantly different across recruitment sites (OR 0.74, 95% CI 0.3–1.7, p ¼ .49).

Time 1 variables associated with outcome at Time 2 Univariate analyses demonstrated no significant associations between any pre-injury variables and outcome at time 2. Similarly there were no significant associations between injury-related variables (such as injury mechanism, severity) and outcome at time 2. As shown in Table 2, there were significant associations between scores from many of the psychological measures at time 1 and outcome at study follow up (time 2). Effect sizes for significant differences between the groups were in the moderate range. These analyses indicated that poor outcome cases at time 2 had endorsed more symptoms at time 1 (RPQ, d ¼ 0.7); greater social and functional problems (RHIFUQ, d ¼ 0.5); as well as greater distress (HADS Anxiety, d ¼ 0.5; HADS Depression, d ¼ 0.6; IPQ-R Emotional Representations, d ¼ 0.6); stronger beliefs about the identity of the condition (IPQ-R Identity, d ¼ 0.5) and severity of injury-related consequences (IPQ-R Consequences, d ¼ 0.6). Examination of the Brief COPE scores indicated that participants who had a poor outcome at time 2 had endorsed greater use of approach coping strategies at time 1 than their counterparts in the good outcome group although these associations did not reach the more stringent threshold chosen for significance (Brief COPE: Approach Coping, d ¼ 0.5, p , .05). Logistic regression analyses were conducted with significant time 1 variables retained from univariate analyses (using “ENTER”) to predict outcome at time 2. As noted above there were no significant time 1 demographic or clinical variables associated with clinical outcome at time 2. After five iterations, of the psychological measures only the Brief COPE Approach Dimension (p , .05) approached significance. The results for all measures entered into the analysis are shown in Table 3. The Hosmer and Lemeshow Test did not reach significance suggesting the data fit the model (p ¼ .45) and estimated variance accounted for by the model ranged between 14% and 21% (Cox and Snell R 2 ¼ .14; Nagelkerke R 2 ¼ .21). Using this model 76.6% of cases were correctly classified.

Examination of IPQ-R dimensions and clinical outcome at time 2 When dimensions of the IPQ-R were examined by outcome using a distribution-based approach, univariate relationships between injury perceptions and outcomes at time 2 were seen. As shown in Table 4, participants endorsing unhelpful perceptions of their injury, that is stronger beliefs at time 1 about the injury identity (IPQ-R Identity, d ¼ 0.3), severity of expected consequences (IPQ-R Consequences, d ¼ 0.2), expected duration of symptoms

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Good outcome at time 21 (n ¼ 94) Mean (SD)

Poor outcome at time 21 (n ¼ 31) Mean (SD)

Mean difference (95% Confidence Interval)

p-value

Measure 2

RPQ Total Score RHIFUQ Total Score 2 HADS 2 Anxiety Depression IPQ-R 3 Identity Scale Timeline A/C Consequences Personal Control Treatment Control Illness Coherence Timeline Cyclic Emotional Representations Brief COPE 4 Approach Dimension5 Avoidance Dimension5 Social Coping Dimension5 Active Coping Planning

Time 1

Time 2

Time 1

Time 2

Time 1

Time 2

Time 1

Time 2

22.2 (13.5) 12.5 (1.2)

13.8 (11.8) 5.8 (7.0)

33.3 (15.2) 18.0 (10.8)

29.9 (8.7) 20.4 (7.6)

-11.1 (-17.3, -4.9) -5.5 (-10.0, -1.1)

-16.2 (-20.8, -11.6) -14.5 (-17.7, -11.4)

.001 .015

.000 .000

6.7 (3.9) 4.6 (3.6)

6.0 (3.6) 2.9 (3.1)

8.8 (4.2) 6.9 (4.4)

8.9 (4.6) 6.8 (3.9)

-2.1 (-3.8, -0.4) -2.4 (-4.1, -0.6)

-2.9 (-4.5, -1.3) -3.9 (-5.4, -2.4)

.016 .009

.000 .000

26.3 (3.7) 13.0 (3.5) 15.9 (5.7) 22.5 (4.0) 17.5 (3.4) 18.5 (3.8) 11.5 (3.5) 15.3 (5.1)

24.2 (4.6) 18.0 (3.3) 23.3 (3.7) 22.0 (3.8) 17.9 (2.7) 16.5 (3.5) 12.9 (2.7) 16.5 (4.3)

28.3 (3.0) 14.1 (4.0) 19.2 (4.7) 22.4 (3.6) 18.2 (3.3) 16.9 (4.8) 12.2 (3.4) 18.5 (5.3)

27.4 (2.8) 19.5 (3.5) 24.9 (3.0) 21.7 (3.4) 18.4 (2.7) 15.7 (3.2) 14.2 (1.9) 19.0 (3.8)

-2.0 (-3.3, -0.7) -1.2 (-2.8, 0.5) -3.3 (-5.5, -1.0) 0.1 (-1.5, 1.7) -0.7 (-2.1, 0.7) 1.6 (-0.3, 3.5) -0.6 (-2.1, 0.8) -3.3 (-5.5, -1.1)

-3.2 -1.6 -1.7 0.3 -0.5 0.8 -1.3 -2.5

(-4.9, -1.5) (-3.0, -0.1) (-3.0, -0.3) (-1.2, 1.7) (-1.6, 0.7) (-0.5, 2.2) (-2.1, -0.4) (-4.1, -0.9)

.003 .161 .005 .902 .315 .101 .391 .004

.000 .034 .014 .701 .417 .224 .004 .003

33.1 (6.2) 19.4 (5.5) 10.1 (3.2) 6.5 (1.4) 6.4 (1.5)

33.2 (6.7) 18.3 (4.4) 10.4 (3.6) 6.5 (1.5) 6.5 (1.6)

35.8 (5.9) 19.0 (5.0) 10.8 (3.2) 6.9 (1.2) 6.9 (1.4)

33.6 (6.1) 19.3 (4.7) 9.7 (3.6) 6.7 (1.5) 6.8 (1.3)

-2.8 (-5.3, -0.3) 0.4 (-1.8, 2.5) -0.7 (-2.0, 0.6) -0.4 (-0.9, 0.1) -0.5 (-1.1, 0.1)

-0.4 -1.0 0.6 -0.2 -0.3

(-3.0, 2.1) (-2.9, 0.9) (-0.9, 2.1) (-0.8, 0.4) (-0.8, 0.3)

.029 .721 .302 .081 .096

.733 .292 .393 .471 .365


TABLE 2 Good outcome group at time 2 compared with poor outcome group at time 2 on psychological measures (n ¼ 125)6

Emotional Support Instrumental Support Self-Distraction Denial Venting Substance Abuse Behavioural Disengagement Self Blame 1

5.8 (1.4) 5.8 (1.5) 5.1 (1.9) 3.4 (2.0) Time 1 4.9 (1.8) 5.2 (1.7) 5.1 (1.7) 2.7 (1.2) 4.2 (1.5) 2.6 (1.4) 2.8 (1.3) 4.6 (1.9)

6.0 (1.5) 6.0 (1.5) 4.8 (2.1) 3.5 (2.1) Time 2 5.1 (1.9) 5.3 (1.9) 5.3 (1.7) 2.5 (0.9) 3.8 (1.5) 2.6 (1.3) 2.8 (1.2) 4.1 (1.7)

6.5 (1.5) 6.8 (1.2) 4.7 (2.0) 4.1 (2.3) Time 1 5.4 (1.9) 5.5 (1.9) 5.6 (1.5) 2.9 (1.7) 3.7 (1.6) 3.0 (1.8) 2.9 (1.2) 4.1 (1.9)

5.8 (1.7) 6.2 (1.5) 4.4 (2.0) 3.7 (2.2) Time 2 4.8 (2.2) 4.9 (1.8) 5.2 (1.9) 2.9 (1.3) 3.8 (1.6) 2.7 (1.4) 2.8 (1.1) 4.5 (1.7)

-0.7 (-1.3, 0.0) -1.0 (-1.5, -0.5) 0.5 (-0.4, 1.3) -0.6 (-1.6, 0.3) Time 1 -0.5 (-1.3, 0.3) -0.2 (-1.0, 0.5) -0.4 (-1.1, 0.2) -0.2 (-0.8, 0.5) 0.5 (-0.2, 1.1) -0.4 (-1.1, 0.3) -0.1 (-0.6, 0.5) 0.4 (-0.4, 1.2)

0.2 -0.2 0.3 -0.2

(-0.5, 0.9) (-0.8, 0.4) (-0.5, 1.2) (-1.1, 0.7) Time 2 0.3 (-0.6, 1.2) 0.4 (-0.4, 1.1) 0.0 (-0.7, 0.8) -0.5 (-0.9, 0.0) -0.1 (-0.7, 0.6) -0.2 (-0.7, 0.4) 0.0 (-0.5, 0.5) -0.4 (-1.1, 0.4)

.038 .000 .263 .173 Time 1 .239 .568 .213 .606 .175 .289 .838 .288

.616 .530 .436 .659 Time 2 .518 .358 .938 .038 .821 .588 .994 .329

Time 1 scores n ¼ 147; Time 2 scores n ¼ 125. 2High scores on the RPQ; RHIFUQ; HADS scales represent poorer status (more symptoms and problems). High scores on IPQ-R scales and subscales represent more strongly held beliefs about the condition. 4High scores on Brief COPE subscales represent greater use of the respective coping strategy. 5Dimension scores derived from factor analysis of the Brief COPE by Snell et al. (2011). 6Independent sample t-tests.

3


Positive Reframing Acceptance Humour Religion

347

348


TABLE 3 Logistic regression of significant time 1 univariate variables on poor outcome on average of seven months after MTBI (n ¼ 125) Final Model Variablesa

B

SE B

df

Significance

Exp (B) (95% CI Exp (B))

Brief COPE Approach Dimensionb

0.096

0.043

1

0.026

1.1 (1.0, 1.2)

HADS Depression

0.096

0.083

1

0.243

1.1 (1.0, 1.2)

Anxiety IPQ-R Identity

0.040 0.053

0.071 0.086

1 1

0.577 0.536

1.0 (0.9, 1.1) 1.1 (0.9, 1.2)

Consequences

0.011

0.059

1

0.857

1.0 (0.9, 1.2)

Emotional Representations

0.047

0.060

1

0.431

1.0 (0.9, 1.2)

a Model after five iterations using ENTER. bDimension scores derived from factor analysis of the Brief COPE (Snell et al., 2011).

(IPQ-R Timeline Acute Chronic, d ¼ 0.2) and emotional impact (IPQ-R Emotional Representations, d ¼ 0.3) had greater odds of poor outcome. Conversely, participants endorsing helpful injury perceptions, that is weaker beliefs at baseline about the identity, expected consequences and emotional impact (IPQ-R: Identity, d ¼ 0.2; Consequences, d ¼ 0.2; Emotional Representations, d ¼ 0.3) had greater odds of good outcome at time 2. These effect sizes were small to moderate.

Changes in injury perceptions, coping styles and distress, over time and by clinical outcome Table 5 shows the results of analyses of mean changes in psychological measure scores between time 1 and 2 for the whole sample (n ¼ 125). These results show there was significant lessening of symptoms (RPQ) and functional difficulties with time (RHIFUQ). Participants as a group also reported less distress at time 2 (HADS Depression), and weaker beliefs about the identity of the condition (IPQ-R Identity). Notably, participants reported significantly stronger beliefs over time about the expected duration and severity of consequences but improved understanding of the condition (IPQ-R Timeline Acute/Chronic, Timeline Cyclic, Consequences, and Illness Coherence). There were no significant changes in participant coping styles for the sample as a whole (Brief COPE). However, when changes in scores on psychological measures were examined according to clinical outcome there were significant differences in the

349

MTBI OUTCOME: ASSOCIATIONS WITH INJURY BELIEFS AND COPING TABLE 4 Associations between IPQ-R scores at time 1 and outcome at time 2 (n ¼ 125)1

IPQ-R Subscale

Helpful perceptions at Time 1 N (%)

Identity Scale Good outcome (n ¼ 93) Poor outcome (n ¼ 31) OR (95% CI) Timeline Acute-Chronic Good outcome (n ¼ 94) Poor outcome (n ¼ 31) OR (95% CI) Consequences Good outcome (n ¼ 94) Poor outcome (n ¼ 31) OR (95% CI) Illness Coherence Good outcome (n ¼ 94) Poor outcome (n ¼ 31) OR (95% CI) Personal Control Good outcome (n ¼ 92) Poor outcome (n ¼ 29) OR (95% CI) Treatment Control Good outcome (n ¼ 92) Poor outcome (n ¼ 30) OR (95% CI) Timeline Cyclic Good outcome (n ¼ 94) Poor outcome (n ¼ 31) OR (95% CI) Emotional Representations Good outcome (n ¼ 94) Poor outcome (n ¼ 31) OR (95% CI) 1

p-value

Unhelpful perceptions at Time 1 N (%)

p-value

36 (38.7) 20 (64.5) 2.9 (1.2, 6.7)

.012

43 (46.2) 9 (29.0) 0.5 (0.2, 1.1)

.093

41 (43.6) 12 (38.7) 0.8 (0.4, 1.9)

.632

41 (43.6) 19 (61.3) 2.0 (0.9, 4.7)

.088

49 (52.1) 9 (29.0) 0.4 (0.2, 0.9)

.025

41 (43.6) 19 (61.3) 2.0 (0.9, 4.7)

.088

43 (45.7) 12 (38.7) 0.7 (0.3, 1.7)

.494

40 (42.6) 15 (48.4) 1.3 (0.6, 2.9)

.570

42 (45.7) 10 (34.5) 0.6 (0.3, 1.5)

.289

41 (44.6) 17 (58.6) 1.8 (0.8, 4.1)

.186

35 (38.0) 16 (53.3) 1.9 (0.8, 4.3)

.140

42 (45.7) 12 (40.0) 0.8 (0.3, 1.8)

.588

44 (46.8) 12 (38.7) 0.7 (0.3, 1.6)

.432

37 (39.4) 14 (45.2) 1.3 (0.6, 2.9)

.569

53 (56.4) 7 (22.6) 0.2 (0.1, 0.6)

.001

36 (38.3) 21 (67.7) 3.4 (1.4, 8.0)

.004

Chi-square tests.

size and direction of changes in scores between outcome groups. These results are shown in Table 6. Compared with those with poor outcome at time 2, as might be expected, those with good outcome reported reduced functional difficulties at time 2 (RHIFUQ) whereas participants in the poor outcome group reported an increase in functional difficulties over time (d ¼ 0.9). There were also trends for participants in the good outcome group improving over time with respect to levels of distress (HADS Depression, d ¼ 0.4) as well as

350


TABLE 5 Summary of change in scores on psychological measures between time 1 and time 25

Measure RPQ1 Total Score RHIFUQ1 Total Score HADS1 Anxiety Depression IPQ-R2 Identity Scale Timeline A/C Consequences Personal Control Treatment Control Illness Coherence Timeline Cyclic Emotional Representations Brief COPE3 Active Coping Planning Positive Reframing Acceptance Humour Religion Emotional Support Instrumental Support Self-Distraction Denial Venting Substance Abuse Behavioural Disengagement Self-Blame Approach Dimension4 Avoidance Dimension4 Social Coping Dimension4

Time 1 Score M (SD) (n ¼ 147)

Time 2 Score M (SD) (n ¼ 125)

Change from Baseline M (SD) (n ¼ 125)

pvalue5

No items

Possible score (min-max)

16

0 – 64

25.0 (14.7) 17.8 (13.1)

7.2 (13.5)

.000

10

0 – 40

13.9 (10.6)

9.4 (9.5)

4.4 (10.6)

.000

7 7

0 – 21 0 – 21

7.2 (4.0) 5.2 (3.9)

6.7 (4.1) 3.9 (3.7)

0.5 (3.7) 1.2 (4.1)

.139 .001

26.8 (3.6) 13.3 (3.7) 16.7 (5.6) 22.6 (3.8) 17.7 (3.4) 18.1 (4.1) 11.7 (3.5) 16.1 (5.3)

25.0 (4.5) 18.3 (3.4) 23.7 (3.6) 21.9 (3.7) 18.0 (2.7) 16.3 (3.4) 13.2 (2.5) 17.1 (4.3)

18 6 6 6 5 5 4 6

18 6 6 6 5 5 4 6

– – – – – – – –

36 30 30 30 25 25 20 30

1.8 -5.1 -7.0 0.6 -0.3 1.8 -1.5 -1.1

(4.0) (4.2) (5.5) (3.6) (3.4) (4.4) (3.6) (5.7)

.000 .000 .000 .056 .359 .000 .000 .037

2 2 2 2 2 2 2 2

2 2 2 2 2 2 2 2 2

– – – – – – – – –

8 8 8 8 8 8 8 8 8

6.6 (1.3) 6.5 (1.5) 6.0 (1.5) 6.1 (1.5) 5.0 (1.9) 3.6 (2.1) 5.0 (1.8) 5.3 (1.7)

6.5 6.6 5.9 6.0 4.7 3.6 5.1 5.2

(1.5) (1.5) (1.6) (1.5) (2.1) (2.1) (2.0) (1.9)

0.1 -0.1 0.0 0.1 0.4 0.0 0.0 0.1

(1.6) (1.8) (1.9) (1.8) (1.9) (1.6) (1.9) (2.0)

.689 .660 .924 .662 .036 .955 .887 .507

2 2 2 2 2

2 2 2 2 2

– – – – –

8 8 8 8 8

5.3 (1.7) 2.7 (1.3) 4.0 (1.6) 2.7 (1.5) 2.8 (1.2)

5.3 2.6 3.8 2.6 2.8

(1.8) (1.1) (1.5) (1.3) (1.2)

0.0 0.2 0.3 0.1 0.0

(2.0) (1.5) (1.8) (1.4) (1.2)

1.000 .264 .094 .446 .942

2 12

2 – 8 12 – 48

4.4 (1.9) 33.8 (6.2)

4.2 (1.7) 33.3 (6.5)

0.3 (1.6) 0.5 (6.8)

.075 .439

10

10 – 40

19.3 (5.3)

18.5 (4.6)

0.8 (4.7)

.071

4

4 – 16

10.3 (3.2)

10.2 (3.6)

0.1 (3.4)

.754

1 High scores on the RPQ; RHIFUQ; HADS scales represent poorer status (more symptoms and problems). 2High scores on IPQ-R scales and subscales. represent more strongly held beliefs about the condition. 3High scores on Brief COPE subscales represent greater use of the respective coping strategy. 4Dimension scores derived from factor analysis of the Brief COPE (Snell et al., 2011). 5 Paired samples t-test.


351

TABLE 6 Change in scores on psychological measures between baseline (time 1) and study follow up (time 2) according to clinical outcome (n ¼ 125)2

Measure RPQ1 Total Score RHIFUQ1 Total Score HADS1 Anxiety Depression IPQ-R2 Identity Scale Timeline A/C Consequences Personal Control Treatment Control Illness Coherence Timeline Cyclic Emotional Representations Brief COPE3 Active Coping Planning Positive Reframing Acceptance Humour Religion Emotional Support Instrumental Support Self-Distraction Denial Venting Substance Abuse Behavioural Disengagement Self-Blame Approach Dimension1 Avoidance Dimension1 Social Coping Dimension1

Good Outcome at Time 2 M (SD) (n ¼ 94)

8.5 (13.9)

Poor Outcome at Time 2 M (SD) (n ¼ 31)

3.4 (11.6)

Mean Difference (95% Confidence Interval)

p2value2

5.1 (20.4, 10.6)

.049

6.7 (10.4)

22.3 (8.4)

9.0 (5.3, 12.7)

.000

0.7 (3.5) 1.6 (3.7)

20.1 (4.1) 0.1 (4.8)

0.8 (20.8, 2.5) 1.5 (20.4, 3.4)

.323 .112

2.2 (4.1) 25.0 (4.3) 27.4 (5.8) 0.6 (3.7) 20.3 (3.4) 2.0 (4.4) 21.7 (3.6) 21.3 (5.6)

0.9 (3.3) 25.4 (4.0) 25.8 (4.2) 0.8 (3.4) 20.1 (3.4) 1.3 (4.2) 22.0 (3.6) 20.5 (5.8)

1.2 (22.2, 2.7) 0.4 (21.3, 2.1) 21.6 (23.9, 0.6) 20.2 (21.7, 1.3) 20.2 (21.6, 1.2) 0.8 (21.0, 2.5) 0.7 (20.8, 2.2) 20.8 (23.2, 1.6)

.096 .632 .158 .790 .783 .388 .376 .494

0.0 (1.6) 20.1 (1.9) 20.2 (1.8) 20.1 (1.8) 0.4 (1.7) 20.1 (1.3) 20.2 (1.8) 20.0 (2.0) 20.1 (1.9) 0.2 (1.4) 0.4 (1.6) 0.0 (1.3) 20.0 (1.3)

0.2 (1.3) 0.1 (1.8) 0.7 (2.0) 0.7 (2.0) 0.3 (2.2) 0.3 (2.2) 0.5 (2.0) 0.6 (2.2) 0.3 (2.1) 20.1 (1.9) 20.1 (2.0) 0.3 (1.8) 0.0 (0.8)

20.2 (20.8, 0.3) 20.2 (21.0, 0.5) 20.8 (21.6, 0.0) 20.8 (21.6, 0.0) 0.1 (20.7, 1.0) 20.4 (21.1, 0.2) 20.8 (21.6, 0.0) 20.6 (21.4, 0.3) 20.4 (21.3, 0.4) 0.3 (20.5, 1.0) 0.5 (20.3, 1.3) 20.2 (20.9, 0.5) 20.1 (20.5, 0.4)

.433 .549 .042 .047 .774 .183 .064 .199 .319 .446 .203 .461 .793

0.5 (1.7) 20.1 (6.7) 1.1 (4.7)

20.3 (1.3) 2.2 (6.8) 20.3 (4.4)

0.8 (0.2, 1.4) 22.3 (25.2, 0.5) 1.4 (20.5, 3.2)

.009 .103 .136

20.2 (3.4)

1.1 (3.4)

21.3 (22.7, 0.1)

.061

1 Dimension scores derived from factor analysis of the Brief COPE (Snell et al., 2011). 2Independent samples t2test.

352


weakening of perceptions of the identity of the condition (IPQ-R Identity, d ¼ 0.3). Both groups reported stronger perceptions over time about the severity of injury consequences although participants in the good outcome group endorsed larger changes on average than those with a poor outcome at time 2 (IPQ-R Consequences, d ¼ 0.3). Differences also emerged between the groups in the direction of changes in coping over time as measured with the Brief COPE. Compared with those with poor outcome at time 2, participants in the good outcome group reported increased use of approach coping strategies with time (Brief COPE Subscales: Positive Reframing, d ¼ 0.4; Acceptance, d ¼ 0.4), increased use of social support (Emotional Support, d ¼ 0.4) and less self-blame (Self Blame, d ¼ 0.5). At time 2 the poor outcome group by comparison, reported reduced use of approach coping strategies, reduced use of social support and an increased tendency to self-blame.

DISCUSSION This research sought to investigate the nature of participant perceptions of and adjustment to a recent MTBI guided by a theoretically derived self-regulation model of health behaviour (Leventhal’s CSM). Specifically, it investigated whether components of the CSM (injury perceptions, coping and distress) were associated with clinical outcomes over time. Empirical examination of such psychological constructs may extend current descriptive models of MTBI recovery and provide more information about risk factors and treatment targets.

Functional recovery In general and as expected, when the whole sample was examined, reduced symptoms and functional difficulties were endorsed over time. However, when changes in scores were examined on the basis of outcome, differences between the groups regarding both size and direction of changes in scores emerged. Participants with a good outcome at time 2 reported greater overall reduction in functional problems than their counterparts in the poor outcome group. While some reduction in symptoms was evident in those with poor outcome at time 2 these participants on average endorsed increased social and functional problems with time. These results are consistent with previous research demonstrating that greater symptom load early after injury is associated with poor MTBI outcome over time (Kashluba et al., 2008; Stulemeijer et al., 2008; Sigurdardottir, Andelic, Roe, Jerstad & Schanke, 2009). Additionally, the finding that participants with poor outcome at time 2 endorsed increased social and functional problems over time is consistent with discussions in the literature regarding accumulating problems and increasing complexity of MTBI presentations with time (Ruff, 2003, 2005;


353

Iverson, 2005). For example, Ruff and colleagues (Ruff, Camenzuli & Mueller, 1996; Ruff, 2003, 2005) suggested that a cumulative stress formulation contributes to understandings regarding the PCS. Results from the present study provide some empirical support for this theoretical discussion. Rates of poor outcome in the present sample were higher than the often cited 5–15% cases that demonstrate poor recovery after a MTBI (Iverson, 2005). However, the rates of poor outcome across a range of recently published prospective studies are highly variable. For example, a collection of recent studies cited rates of poor outcome (based on the ICD-10 post-concussion syndrome criteria set) ranging between 26% and 51% at six months postinjury and 27.3% to 50% at 12 months (Stulemeijer et al., 2008; Heitger et al., 2009; Røe, Sveen, Alvisa˚ker & Bautz-Holter, 2009; Sigurdardottir et al., 2009). The rates reported in the present study are not inconsistent with (and actually slightly better than) this body of research. This is a fraught issue and much debated in the literature. Variable rates seem to be related to variability in study methods such as length of study follow up, choice of outcome criteria and measures).

CSM components (injury perceptions, coping, distress) and outcome after MTBI The patterns of injury perceptions demonstrated by participants would be predicted by Leventhal’s CSM and consistent with the increasing body of empirical evidence regarding the influence of components of the CSM on health outcomes in other patient populations (Hagger & Orbell, 2003). Specifically, the present study suggested that identity, timeline, and consequences beliefs as well as emotional representations of the injury were particularly salient and associated with outcomes over time. These may be important injury perceptions to target in the early stages of injury recovery because they may become fixed and less malleable with time. Previous research does suggest that such injury perceptions are amenable to change through early intervention (Petrie, Cameron et al., 2002). Leventhal’s CSM suggests that individuals’ perceptions about their health condition may change over time depending on the course or outcome of their condition (Leventhal, Leventhal, Ellis, Buick & Weinman, 1998, 2001). Our results suggested that, over time, participants, regardless of outcome, changed their perception of the impact of MTBI and appeared to see the injury as more serious than they did earlier following injury. These results are consistent with research that has suggested that people in general know little about MTBI and the PCS (MacKenzie & McMillan, 2005; Mulhern & McMillan, 2006). As a result of this knowledge gap participants may have initially minimised the implications of their injury. Based on clinical experience and consistent with this assumption, patients presenting to health services early after

354


injury are often told they can return to work or study after a few days convalescence. Analysis of the return to work rates (data not shown) indicated that many participants in the present study required several weeks before resumption of usual levels of activity and participation. The CSM would predict that when there is conflict between expected and actual recovery, individuals might re-appraise the seriousness of their health condition with resulting changes in injury perceptions around core components of the model. The results from the present study appear consistent with this prediction. One of the key principles of the CSM is that coping is a mediator between illness perceptions and various health outcomes (Leventhal et al., 1998, 2001; Cameron, 2003) and this is widely discussed in the coping literature (Godfrey, Knight & Partridge, 1996; Stanton, Revenson & Tennen, 2007; Taylor & Stanton, 2007). However, results from empirical studies examining the role of coping as a mediator have been inconsistent (Hagger, Chatzisarantis, Griffin & Thatcher, 2005; Kaptein, Helder, Scharloo, Van Kempen, Weinman et al., 2006; Llewellyn et al., 2007). The results of the present study suggested relationships existed between choice of coping style and outcome that might be specific to the MTBI population. However, these relationships were not consistent across analyses and many of the associations were marginally significant at best. Further, some of these findings were inconsistent with research in other health conditions. For example, the results showed that participants in the poor outcome group at time 2 had endorsed greater use of approach coping strategies earlier after their injury compared with participants in the good outcome group. This is inconsistent with a body of research suggesting approach coping strategies are associated with better health outcomes (Stanton et al., 2007). However, when coping was examined over time and by outcome, the results were much more consistent with this previous research. Participants with a good clinical outcome at time 2, as a group, endorsed increased use of approach coping strategies (positive reframing, acceptance, seeking support) between time 1 and 2. Participants in the poor outcome group at time 2, in contrast, reported reduced use of these coping strategies and increased tendency to self-blame. This suggests that use of active approach coping could be unhelpful in the early stages following an MTBI when gradual and paced resumption of usual routines and activities is preferable to early over-exertion (Borg et al., 2004; McCrea et al., 2009; Snell et al., 2009). However, the use of such active coping strategies may become more helpful with time. More research is required to examine the relationships between coping and outcome after MTBI. Finally, there were significant associations between distress (HADS scores) and outcome in the present study. Participants who were more distressed at time 1 had greater odds of poor outcome at time 2 and for demonstrating persisting high distress with time. These results are consistent with previous MTBI studies where significant associations between anxiety,


355

depression and development of PCS have been identified (Moore, TerryberrySpohr & Hope, 2006; Panayiotou et al., 2010; Lange et al., 2011). The CSM would predict reciprocal associations between increased psychological distress, illness perceptions, coping and outcome and there is evidence to support this in other patient populations (Cameron, 2003). Cameron (2003) described the way negative affect such as anxiety and depression might influence illness perceptions and might also act as a mediator between choice of coping style and outcome. Psychological distress may also have more direct effects on outcome after MTBI. Stress-related changes in autonomic and neuroendocrine functioning, including activation of the hypothalamus-pituitary-adrenal (HPA) axis, and the sympathetic nervous system, may lead to increased anxiety and distress (Deary, Chalder & Sharpe, 2007). Increased distress and anxiety may increase selective attention to symptoms, leading to strengthening of injury perceptions and search for an illness label, increasing risk for symptom misattribution (Cameron, 2003; Stanton et al., 2007) and poorer subsequent outcome. Future MTBI research could examine how distress might be associated with outcomes, that is whether distress mediates between factors such as injury beliefs, coping and outcome as would be predicted by the CSM, and/or has a more direct effect on injury adjustment.

Clinical applicability of findings The study findings support previous suggestions that recovery after MTBI can be influenced by psychological factors both during the sub-acute recovery period and over time (Whittaker et al., 2007). The CSM appears to be a useful theoretical framework for understanding atypical recovery and directing research focus so that the broad collection of hypothesised psychological perpetuating factors can be systematically investigated. The results also provide support for the CSM both for predicting those at risk for poor outcome and identifying potential early treatment targets for MTBI. Guided by the model, these targets might include management of distress (emotional representation dimension), understanding of the condition (coherence), recovery expectations and timeframes (consequences and timeline dimensions), action plans for managing symptoms, and gradually resuming usual levels of activity and participation (control dimension, coping procedures). More research is required to examine the role of coping in MTBI recovery, and the influence of other factors such as injury perceptions held by others, such as MTBI treatment providers and insurers.

Limitations The study recruitment procedure increased potential for selection bias; participants were recruited on presentation to hospital-based healthcare services

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following injury and accordingly people sustaining MTBIs but not presenting to either of the two recruitment sites or to health services at all, were missed. A proportion of potential participants presenting to the Emergency Department setting could not be contacted and these people appeared to be younger and male. The main reasons for non-recruitment were inaccurate contact information in the clinical record or no response to attempts to contact. This group (young and male) tend to be difficult to recruit into MTBI studies (McCullagh & Feinstein, 2003) and are those who are also less likely to present for treatment (Snell & Surgenor, 2006). Further, participants who agree to participate in health research may be different to those who decline to participate. McCullagh and Feinstein (2003) retrospectively reviewed 626 participants who had been approached regarding participation in MTBI research projects in Canada. The results identified a bias toward more severe MTBI in those who participated in research. For the present study, this suggests that if a systematic recruitment bias indeed occurred, it is likely that those with milder injuries were under-represented rather than those with clinically significant problems. Loss to follow up is a particular challenge for longitudinal research and MTBI studies typically report significant attrition rates (McCullagh & Feinstein, 2003; Graham, 2009). For example, in a recent study by Røe et al. (2009), the reported rate of loss to follow up over a period of 12 months was 54%. In the present study 22 participants did not complete the second visit, reflecting a loss to follow up of 15%. Lundin, De Boussard, Edman and Borg (2006) suggested that such loss to follow up in MTBI samples increases risk for over-representation of participants with a high concern for their health, and thus potential for inflated estimates of poor outcome. The moderate rate of dropouts in the present study needs to be considered when the results are examined. The results of the present study may be specific to MTBI and generalising findings to the wider trauma group is problematic. One study was found that examined injury perceptions using the IPQ-R in participants with sportsrelated musculoskeletal injuries (Hagger et al., 2005). This study found different associations between some of the IPQ-R dimensions and outcomes to those reported above. Future research examining components of Leventhal’s CSM and MTBI should include a wider trauma control group to examine these potential population-specific differences. While the sample size may have had sufficient power to accurately detect desired effects, there are concerns regarding the number of analyses conducted. This relates to risk for Type I error associated with multiple variables and analyses (Maxwell, Kelley & Rausch, 2008). In mitigation, many of the results were highly significant. However, it was for this reason a more stringent alpha level was chosen for evaluation of statistical significance and p values were reported to three decimal places to provide more precise


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indication of significance. Further, the regression analyses were limited by a number of factors. These included the cases to predictor variable ratio, correlations between measures and therefore overlap in constructs. However, as a first study of this type, we were focused on early preliminary model building, and therefore correlation between some variables was to be expected and is a strength. A priori power analysis estimates suggested the study would have adequate power to detect moderate effects using the convention established by Cohen (Cohen, 1988; Maxwell et al., 2008; Munro, 2005) for univariate testing. The analyses produced a range of moderate and sometimes large effects for measures including the RPQ, RHIFUQ, HADS and various IPQ-R subscales. However, the effect sizes for some of the IPQ-R subscales (e.g., Personal and Treatment Control) and the Brief COPE dimension and subscale scores were variable and generally small and non-significant. These results could be interpreted as indicating the control and cause dimensions of the CSM and coping have limited influence on outcome after MTBI although this is inconsistent with research examining the influence of these factors and outcome in other health conditions (Hagger et al., 2005; Hagger & Orbell, 2003). It is more likely, however, that there are associations between these constructs and MTBI outcome but these were not demonstrated by the present study because of problems with choice of study measures. For example, recent factor analysis of the IPQ-R modified for MTBI (Snell et al., 2010) suggested modifications are required before the control and cause scales can be used confidently with MTBI participants. More research is required to examine these aspects. Most of the demographic, clinical and post-injury indicators of functioning were based on self-report. Where possible, reported injury information, preinjury medical history including psychiatric illness, and substance use was verified by review of clinical records although there were inconsistencies in the range of information recorded in these records. This means that reporting bias could not be excluded and risks for over-reporting of symptoms in MTBI/PCS samples using self-report questionnaires have been demonstrated (Iverson, Brooks, Ashton & Lange, 2010). In addition, relying on self-report for information, such as substance use and history of psychiatric illness, may have resulted in under-reporting of relevant conditions (Iverson, Lange, Brooks, Ashston-Rennison, 2010). Finally, examination of treatment data indicated that participants meeting criteria for poor outcome at time 2 were more likely to have had treatment than those in the good outcome group. The iatrogenic effects of clinical interactions are widely discussed in the MTBI literature (Iverson, 2005, 2006; Iverson & Lange, 2003; Suhr & Gunstad, 2005). This is a potential confounding factor and raises a concern that treatments provided to participants may have been unhelpful. This is an important issue and more research is required

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to guide clinical decisions regarding the form and content of MTBI intervention in clinical practice. In addition, the level of treatment follow up received by study participants may not be consistent with that usually experienced by patients in other health jurisdictions because of the no-fault injury insurance system that exists in New Zealand. Study results should be considered with this caveat in mind.

CONCLUSIONS This research examined whether a theoretically derived self-regulation model of health behaviour such as Leventhal’s Common Sense Model (CSM), could extend current largely descriptive models of MTBI recovery and inform approaches to research and clinical management. Consistent with Leventhal’s CSM, those at time 1 who attributed many symptoms to their MTBI, expected this to have severe lasting consequences and greater emotional impact and were more likely to have poor clinical outcomes six months later (time 2). Coping appeared to have important associations with outcome but the results were inconsistent. More research is required to examine whether coping mediates or influences outcomes more directly. A theoretically derived, coherent model of health behaviour such as Leventhal’s CSM, offers a reasoned approach to examining psychological factors with potential for both predicting those at risk for atypical MTBI recoveries, and development of effective clinical and research approaches to intervention.

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