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Cochrane Database of Systematic Reviews Protocol - Intervention

Psychological interventions for persisting postconcussion symptoms following traumatic brain injury

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Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To assess the benefits and harms of psychological interventions for people with persisting postconcussion symptoms.

Background

Description of the condition

The annual incidence rates of traumatic brain injury (TBI) are rising worldwide (Roozenbeek 2013), ranging from 91 per 100,000 population, Thurman 1999, to 146 per 100,000 population (Feigin 2013). A previous review indicated that 70% to 90% of TBI cases are diagnosed as mild (Cassidy 2004). Mild traumatic brain injury (mTBI) is often determined by duration of loss of consciousness (less than 30 minutes), duration of post‐traumatic amnesia (less than 24 hours), and/or Glasgow Coma Scale score of 13 to 15 (Carroll 2004). Following mTBI, people may experience temporary physical, cognitive, and psychological symptoms (Hall 2005).

These symptoms are widely expected to resolve within three months with little or no intervention. However, early studies reported symptoms persisting for more than three months following mTBI in approximately 15% to 20% of cases (Alexander 1995). These findings have been widely cited (Alexander 1992; Brown 1994; Wylie 2015), and there is ongoing debate surrounding the prevalence, nature, and underlying causes of persisting symptoms (Bigler 2008; Iverson 2005; Larrabee 2013; Rohling 2011). Controversies aside, it is evident that a proportion of people with mTBI experience persisting symptoms that are disproportionate to their injury, and these often have a significant impact on their quality of life (Emanuelson 2003). Furthermore, long‐term symptoms (persisting for over 18 months) have been linked with high levels of postinjury unemployment, anxiety, depression, and lower quality of life (King 2011).

Current diagnostic manuals acknowledge persisting symptoms following mild to moderate TBI, although they differ in the diagnostic labels used. The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD‐10) refers to "postconcussional syndrome", which includes headaches, dizziness, fatigue, irritability, and difficulties with concentration and memory (World Health Organization 1992). The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM‐IV) included "postconcussional disorder" (American Psychiatric Association 2000), which was similar to postconcussional syndrome in the ICD‐10 with the additional requirement of evidence from cognitive testing. However, the DSM‐V no longer refers to these difficulties as a distinct disorder and instead describes "neurocognitive disorder due to traumatic brain injury", which does not consistently refer to the severity of injury (American Psychiatric Association 2013). The DSM‐V also acknowledges that some people who have sustained a TBI may experience persisting symptoms, which include emotional symptoms (irritability, frustration, tension, anxiety, and emotional liability), personality changes (disinhibition, apathy, suspiciousness, and aggression), and physical disturbances (headache, fatigue, insomnia, and dizziness).

The usefulness of diagnostic labels for these symptoms has been questioned (Arciniegas 2001; Boake 2004; Boake 2005). Furthermore, the variation in diagnostic criteria for persisting symptoms is also reflected in the research literature, where studies often describe and characterise persistent symptoms following TBI in different ways (Iverson 2010). Some researchers and clinicians working in the field of brain injury have been reluctant to use diagnostic labels and have described persisting symptoms that are considered disproportionate to the organic injury as "persisting post‐concussion symptoms", rather than a disorder or a syndrome (Marshall 2012).

For the purposes of this review, we will refer to symptoms commonly associated with postconcussional syndrome (ICD‐10) and persisting symptoms of neurocognitive disorder due to mTBI (DSM‐V) as persisting postconcussion symptoms (PPCS).

Assessment of PPCS following mTBI may be further complicated by the variation in assessment tools used by researchers and clinicians. Although there is no consensus about a standard assessment procedure, the Rivermead Postconcussion Symptoms Questionnaire, King 1995, and the Neurobehavioural Symptom Inventory, Cicerone 1995, appear to be used most frequently in the literature.

Given the persistent nature of these difficulties, the potential impact on family and carers should also be considered. Research indicates that family and carers of individuals who have sustained a TBI experience significant amounts of stress, depression, and emotional distress (Chan 2009). Feelings of loss, isolation, and anxiety are reported by partners of individuals who have sustained TBIs of varying severity (Liss 1990). The specific impact of PPCS following mTBI on family and carers remains unclear.

There is mounting evidence that symptoms similar or identical to PPCS often occur in the absence of TBI, including in people experiencing chronic pain (Iverson 2005; Smith‐Seemiller 2003), psychological difficulties (Ruff 2011), and in healthy individuals (Chan 2001; Donnell 2012; Iverson 2003; Waljas 2015). This may reflect the existence of general psychological mechanisms contributing to the development and maintenance of PPCS. Hence, it has been hypothesised that psychological interventions may be able to prevent the development or maintenance of PPCS following mTBI, or to treat postconcussion symptoms that have already become persistent.

Description of the intervention

The available evidence consists of studies evaluating a number of different psychological interventions for the cluster of symptoms that people may experience as PPCS. These studies can be divided into two groups: those that aim to prevent the development and maintenance of PPCS immediately following mTBI, and those that aim to treat postconcussion symptoms that have become persistent. The aim of the current review is to evaluate the evidence for the latter group of studies.

Interventions for persising postconcussion symptoms have mainly involved psychoeducation, psychotherapy, cognitive strategies, and counselling.

  • Psychoeducation provides individuals with information about their condition and any associated difficulties they may experience.

  • Psychotherapy interventions support individuals to manage their psychological difficulties and modify behaviours. Examples of psychotherapies include cognitive behaviour therapy, mindfulness‐based therapies, compassion‐focused therapy, and acceptance and commitment therapy.

  • Cognitive strategy interventions engage individuals in exercises that aim to improve cognitive functioning. They may also include compensatory strategies intended to reduce the impact of cognitive deficits, such as the use of external memory aids.

  • Counselling interventions allow individuals to talk about their problems and feelings in a confidential and dependable environment.

How the intervention might work

The overarching objective of psychological interventions for PPCS is to reduce psychological distress and to promote psychological and cognitive strategies that will improve the individual's level of function and reduce symptoms.

  • Psychoeducation interventions improve knowledge and understanding of the target condition. This may empower individuals, giving them a greater sense of control over their condition and defusing negative stereotypes.

  • Psychotherapies employ psychological methods to support individuals to overcome difficulties in a desired way. The aim of psychotherapy is to increase psychological well‐being and modify unhelpful behaviours, thoughts, and beliefs.

  • Cognitive strategies are generally divided into two different categories: restorative interventions, which aim to improve cognitive functioning through repetition and gradually increasing demands; and compensatory strategies, which aim to reduce the negative impacts of cognitive difficulties through reducing reliance on areas of cognitive deficit.

  • Counselling allows individuals space to reflect and discuss their experience in order to reach their own understanding of what is happening. This may also empower individuals with a greater sense of control over their experiences.

Why it is important to do this review

People experiencing PPCS may present to a variety of services including primary care, community brain injury, and mental health services. The complex and clinically challenging nature of this presentation can place a significant burden on family and friends, healthcare providers, and insurers (Wood 2004). There are also economic implications: return‐to‐work rates are poor (King 2011), and there are often issues around litigation (Tsanadis 2008). Despite this complexity, research exploring the effectiveness of interventions specifically for PPCS has been limited, and there is no consensus about appropriate and effective interventions for this phenomenon. This may be due in part to the confusion around the aetiology and maintaining factors of PPCS being translated into a vague and uncertain picture of care.

There are currently no clinical measurements that are known to predict which individuals will experience poor outcomes following mTBI (Arciniegas 2005), and current National Institute for Health and Clinical Excellence guidelines for brain injury make no reference to PPCS, with little mention of mTBI (NICE 2014). This may be due in part to limited evidence on what interventions are most effective.

Two previous reviews investigated the effectiveness of rehabilitation interventions following mTBI (Ponsford 2005; Snell 2009). Both reviews found little available evidence for the management of mTBI, which was generally of poor methodological quality, and concluded that there was a need for more research into the management of symptoms following mTBI. Sayegh 2010 reviewed the evidence for psychological interventions specifically aimed at PPCS and drew similar conclusions. Sayegh 2010 found few high‐quality studies investigating interventions for PPCS and included studies that had significant methodological weaknesses, and concluded that cognitive behavioural interventions appeared to show some consistent benefits, while psychoeducation approaches showed mixed results.

A systematic review of the recent literature may identify which interventions are most effective, or show most promise, in reducing PPCS. This information would be useful for guideline producers, policymakers involved in developing services for people experiencing PPCS, and people interested in identifying promising research directions.

The purposes of this review are (a) to clarify the evidence base to enable commissioners, clinicians, and patients to make appropriate clinical decisions, and (b) to inform the development of further randomised controlled trials investigating psychological interventions for PPCS.

Objectives

To assess the benefits and harms of psychological interventions for people with persisting postconcussion symptoms.

Methods

Criteria for considering studies for this review

Types of studies

We will include individually or cluster randomised controlled trials and quasi‐randomised controlled trials.

Types of participants

We will include studies investigating interventions for adults (over 16 years old) who have been classified by study authors as experiencing persisting postconcussion symptoms, postconcussion syndrome, neurocognitive disorder, or neuropsychological symptoms persisting beyond three months following a mild to moderate TBI.

We will exclude participants who have a diagnosis of other neurological disorders that may affect cognition such as dementia, Parkinson’s disease, or multiple sclerosis.

We will include studies using heterogenous samples where 80% of the sample meet the inclusion criteria. We will also include studies where subgroup analyses are provided allowing extraction of data for a sample in which 80% meet the inclusion criteria.

Types of interventions

For the purposes of this review, we will define psychological interventions as non‐pharmacological interventions with a primary aim of promoting an individual’s sense of well‐being and reducing emotional distress, and which use techniques derived from psychological theory and practice. These interventions may include, but are not limited to, psychoeducational programmes, cognitive strategies training, counselling, cognitive behavioural therapy, and guided self help. Individual, group, or family therapy interventions will be eligible for inclusion. We will include interventions delivered by neuropsychologists, clinical psychologists, psychologists in training, and other trained professionals. We will also include multicomponent interventions with a psychological element.

We will not exclude studies on the basis of the type of control used. The control may include, but is not limited to, waiting‐list control, treatment as usual, placebo, or non‐psychological interventions. We will also include studies comparing two or more psychological treatments.

Types of outcome measures

Primary outcomes

  1. PPCS symptom scores measured by validated scales such as the Rivermead Post‐Concussion Symptoms Questionnaire (King 1995), or alternative symptom scales designed to assess postconcussion symptoms.

  2. Adverse events during psychological intervention, such as incidents of completed or attempted suicide, loss of employment, reduction in activities, or intensification of symptoms.

  3. Measures of quality of life on validated scales such as the World Health Organization WHOQOL (WHOQOL Group 1998).

Secondary outcomes

  1. Symptom scores on scales designed to measure psychological symptoms commonly associated with PPCS such as depression or anxiety (e.g. the Beck Depression Inventory, 2nd Edition (Beck 1996), the Beck Anxiety Inventory (Beck 1993), and other validated measures).

  2. Treatment satisfaction assessed by validated self report measures.

  3. The number of participants who drop out of psychological therapy for any reason.

  4. Economic outcomes (e.g. return to work, number of appointments with primary care physicians, and referrals to other services).

  5. Measures investigating the impact of the intervention on carers of those with PPCS.

  6. Measures investigating changes in cognitive performance, assessed by standardised cognitive tests such as, but not limited to, the Paced Auditory Serial Addition Task, the Rey Auditory Verbal Learning Test, and the Wechsler Memory Scale.

Search methods for identification of studies

Electronic searches

We will search ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group’s (CDCIG) specialised register.

ALOIS is maintained by the Information Specialists for the CDCIG, and contains studies that fall within the areas of dementia prevention, dementia treatment and management, and cognitive enhancement in healthy elderly populations. The studies are identified through searching:

  1. a number of major healthcare databases: MEDLINE, Embase, CINAHL, and PsycINFO;

  2. a number of trial registers: ISRCTN, UMIN (Japan's Trial Register), and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) (which covers ClinicalTrials.gov, ISRCTN, the Chinese Clinical Trials Register, the German Clinical Trials Register, the Iranian Registry of Clinical Trials, and the Netherlands National Trials Register, among others);

  3. the Cochrane Library' s Central Register of Controlled Trials (CENTRAL);

  4. a number of grey literature sources: ISI Web of Knowledge Conference Proceedings, Index to Theses, Australasian Digital Theses.

View a list of all sources searched for ALOIS on the ALOIS website (www.medicine.ox.ac.uk/alois).

Details of the search strategies run in healthcare bibliographic databases, used for the retrieval of reports of dementia, cognitive improvement, and cognitive enhancement trials, can be viewed in the ‘methods used in reviews’ section within the editorial information about the Cochrane Dementia and Cognitive Improvement Group.

We will run additional searches in MEDLINE, Embase, CINAHL, PsycINFO, ClinicalTrials.gov, and the WHO ICTRP in order to ensure that the searches are as comprehensive and up‐to‐date as possible. The search strategy to be used for the retrieval of reports of trials from MEDLINE (via the Ovid SP platform) can be found in Appendix 1.

Searching other resources

We will complete forward and backward referencing for included studies identified in the searches.

We will contact experts in the area to identify unpublished research.

Data collection and analysis

Selection of studies

Three review authors (PM, CJ, MA) will independently review the titles and abstracts of the studies identified in the searches. We will cross‐check results and exclude irrelevant articles. The same three authors will independently review the full‐text reports to determine eligibility, again cross‐checking results and excluding studies not meeting the inclusion criteria. Disagreements will be discussed and resolved. In the event of there being multiple reports from one study, reports will be linked together. We will generate a final list of included studies.

Data extraction and management

Three review authors (PM, CJ, MA) will independently complete data extraction of the included studies, with cross‐checking of results. Disagreements will be discussed and resolved. We will complete data extraction using standardised data extraction forms.

We will extract the following data from the included studies.

Participants

  • Total sample size

  • Total number of participants allocated to each group

  • Setting

  • Inclusion criteria

  • Age

  • Gender

  • Country

  • Nature of injury

  • Time since injury

Methods

  • Study design

  • Duration of study

  • Sequence generation and allocation concealment

  • Method of blinding

  • Any other concerns about bias

Intervention

  • Type of intervention

  • Duration of intervention

In the event of included studies assessing complex multicomponent interventions, we will use the Template for Intervention Description and Replication (TIDieR) to describe the intervention in detail.

Outcomes

  • Name and definition of outcome

  • Units of measurement

Results

  • Number of participants allocated to each intervention and control group

  • Sample size for each outcome

  • Missing data

  • Summary data for intervention and control groups (e.g. means and standard deviations for all outcomes)

Assessment of risk of bias in included studies

Three review authors (PM, CJ, MA) will independently assess the risk of bias. We will cross‐check the results to identify potential inconsistencies. Disagreements will be discussed and resolved.

We will assess the domains of the current Cochrane tool for assessing risk of bias (Higgins 2011). We will make an overall summary judgement of risk of bias for each study per outcome, followed by an overall judgement per outcome across studies.

We will identify studies at overall low risk of bias for each outcome in order to conduct sensitivity analyses. As blinding of participants and personnel will not be possible, we will not consider a high risk of performance bias when making an overall judgement of risk of bias.

Measures of treatment effect

For continuous outcomes, we plan to present effect estimates as mean difference with 95% confidence interval. If an outcome is measured using a variety of scales, then we will present the effect estimates as a standardised mean difference.

For dichotomous outcomes, we will present effect estimates as risk ratios with 95% confidence intervals.

Unit of analysis issues

In the event of studies measuring outcomes at several time points, we will conduct separate analyses for short‐ (up to three months), medium‐ (over three months, up to 12 months), and long‐term (over 12 months) outcomes. If included studies employ cluster randomisation, we will analyse the data using summary data from each cluster.

Dealing with missing data

In the event that data are identified as missing, we will contact study authors for missing data and to determine whether or not data are missing at random. As an intention‐to‐treat analysis is regarded as the least‐biased method to estimate intervention effects (Newell 1992), studies with missing data not employing an intention‐to‐treat analysis will be rated as having high risk of bias and will be excluded from the sensitivity analysis.

Assessment of heterogeneity

Three review authors (PM, CJ, MA) will visually assess the clinical and methodological heterogeneity of the included studies, and where applicable, we will aim to calculate an I2 statistic and use the Chi2 test to assess the statistical heterogeneity. We will judge a Chi2 P value of less than 0.1 and an I2 statistic of greater than 50% as indicating statistical heterogeneity in accordance with the guidelines in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).

Assessment of reporting biases

We will request protocols from study authors to compare planned and reported outcomes.

In order to examine publication bias, we will identify any unpublished data by carrying out a comprehensive search of multiple sources and by requesting unpublished data from study authors. We will also look for small‐study effects to establish the likelihood of publication bias. We will examine funnel plots in the event of there being 10 or more studies that can be combined, in accordance with recommendations in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).

Data synthesis

We will consider the population, type of intervention, control group, follow‐up time, and outcomes measures used when deciding whether or not data to pool data. Where there is significant methodological, clinical, or statistical heterogeneity, studies will not be combined.

It is unlikely that all included studies will present data from psychological interventions that can be combined in a single meta‐analysis. We will pool data from studies investigating psychological interventions of the same type, such as psychoeducation, cognitive behaviour therapy, or counselling.

We will also consider the control intervention when making pooling decisions. In particular, we will separate comparisons of alternative psychological interventions from comparisons with control interventions intended to be inactive.

If there is considerable heterogeneity across studies so that pooling of data is inappropriate, the review will take a narrative approach.

Subgroup analysis and investigation of heterogeneity

Three review authors (PM, CJ, MA) will visually assess clinical and methodological heterogeneity. We will assess statistical heterogeneity using a Chi2 test and an I2 statistic. We will use an alpha value of P = 0.1 to assess significance of the Chi2 test, and will judge an I2 statistic of over 50% as indicative of statistical heterogeneity in accordance with the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).

Sensitivity analysis

If we identify variation in study quality, we will carry out a sensitivity analysis. We will report the analysis for all studies and then compare it to an analysis including only studies at low risk of bias.

Presentation of results: 'Summary of findings' tables

We will assess the overall quality of the body of evidence for each outcome behind each effect estimate using the GRADE approach (Guyatt 2008). GRADE defines the quality of evidence as the extent to which one can be confident that an estimate of effect is close to the true effect size. It takes into account the risk of bias in the included studies, inconsistency between studies, imprecision in the effect estimate, indirectness in addressing the review question, and the risk of publication bias. We will produce a 'Summary of findings' table for each comparison, for each of the following outcomes.

  1. Persistent postconcussion symptoms on dedicated scales

  2. Quality of life

  3. Adverse events during interventions

  4. Depression

  5. Anxiety

  6. Memory

  7. Attention