Introduction
Traumatic brain injury in adults has been proven to have detrimental impairments of memory capabilities (Gottesman, 2003). Research shows that the efficacy of treatment for memory deficits in traumatic brain injury can be beneficial to the restoration of cognitive abilities in patients (Wammes, 2017). Traumatic brain injury (TBI) can be defined as, “a brain injury caused by sudden damage to the brain” (ASHA). This includes loss of consciousness, abnormal cerebral imaging, altered mental status, and posttraumatic amnesia. Studies show that these brain injuries, depending on the location and power, result in a buildup of pressure within the brain region that have been proved to cause both physical and psychosocial problems. TBI Symptoms can either be immediate or delayed but yield a medical diagnosis regardless. Common signs include somatic problems, sensory problems, behavioral difficulties, trouble with thinking skills, speech and language impairments, and swallowing problems (ASHA). More specifically, signs and symptoms of a TBI can be classified into cognitive difficulties, behavioral difficulties, whole body impairments such as chronic fatigue, mood changes, sound or light sensitivities, and slurred speech. For patients these symptoms may look like amnesia and confusion, irritability and aggression, dizziness or chronic imbalance, pupil dilations, nausea, headaches, or voice impairments. The Center of Disease Control (CDC) states that, “1.1 million emergency room visits, and 50,000 deaths are reported each year as a result of TBI”, proving it is imperative to determine the effects and methods to best treat these patients (CDC, 2007).
Treatment for TBIs is highly individualized, however cognitive rehabilitation methods are most commonly addressed for the purpose of restoring a patient’s independence and daily function. “Cognition operates as an integrated system of performance fields and includes various functions within these fields. The fields include attention, memory and learning, thinking or mental organization, affect and expression, and executive functions. Depending on many factors, brain injuries may affect overall patient performance and may have differential effects on performances within these fields” (Carney et al., 1999). Cognitive rehabilitation is comprised of various therapies that are used to restore intellectual, perceptual, psychomotor, and behavioral skills as a result of a TBI (1999). This can either be achieved by designing individual interventions that target specific skills that need improvement, or by modifying the patient’s environment. The prevalence of TBIs and the effect it has on an individual’s daily functioning, it requires a team of specialists to address the impairments. In TBIs speech modalities are directly impacted and yield the assistance of an SLP. The SLPs role in TBI treatment includes, educating patients and their families of the diagnosis, determining appropriate treatment outcomes that, “strengthen cognitive skills and communication modalities for functional independence”, in addition to determining effective compensatory strategies that positively impact the multimodal communication system of a patient (ASHA). This includes using spoken and nonverbal communication, speech-generating devices, or written language to help restore a patient’s cognitive function.
Research indicates the success of cognitive treatment that directly affect a TBI patient’s functioning, more specifically, memory deficits. There are various compensatory strategies and treatment methods that can be administered based on the severity and location of the brain injury in adult populations. Because memory deficits have the ability to severely impair a person’s independence, there are external compensatory strategies and internal compensatory strategies that can be used to help restore functioning after an accident. External compensatory strategies can be broadly defined as modifications to one’s environment for the purpose of restoring memory deficits. For example, using a planner to keep track of tasks, memory computer games, or using Post-Its to label the names various items around the house. These strategies are external aids that effectively address memory deficiencies. Whereas internal compensatory strategies are the use of medicine and pharmacological agents to aid in memory function. Pharmacological intervention is used for the purpose of “reducing neural damage and improving cognitive and behavioral outcomes of TBIs” (Wheaton et al., 2009). Because TBIs clearly impact the brain’s neurochemical and neurological functions, the ability for neurons to fire to different areas of the brain for the purpose of activity, researchers have worked to determine if pharmacological remedies can reverse these neural changes. Although in majority of the studies reviewed, further global research is needed for conclusive outcomes, there is evidence that early administration of pharmacological treatments plays a role in treating TBIs (2009).
The goal of this review is to further explain the evidence-based practice of treatment methods used by speech pathologists to restore memory functions in TBI patients. A commonly used external compensatory strategy that was proven effective for memory deficits in adults with moderately impaired TBI patients is the Memory and Attention Adaptation Training (MAAT). MAAT can be described as a, “brief cognitive-behavioral therapy aimed at enhancing skills for self-managing and coping with cognitive failures in daily life” (Ferguson and Mittenberg, 1996). This can range anywhere from using cell phone paging prompts for daily reminders to Google Calendar notes to activate working memory. Considerable evidence shows the efficacy of using memory and attention training for TBI patient treatment and is practiced by several rehabilitation specialists. Specifically, for speech pathologists, MAAT is integrated into patient’s individualized education programs (IEPs) to help restore verbal memory. The patient’s ability to recall terminology, that can be tested and monitored through a variety of assessments. Whereas, pharmacological treatment, an internal compensatory strategy that targets the neurochemistry of a patient, specifically focusing on the, “major neurotransmitter systems modulating the function of brain regions underlying the relevant cognitive process” (McDonald, 2016). Because damage to the brain’s cells affect one’s ability to send messages to different parts of the body, there are methods to reverse the effects of cerebral damages. External strategies address environmental modifications, whereas internal strategies address the anatomy of brain functioning. The significance of the differing strategies requires further research; However, meta-analyses of both practices have proven the efficacy of treatment for cognitive deficits post-traumatic brain injuries (2016). This paper will address whether external compensatory strategies improve memory in mild to moderately impaired TBI adult patients more than internal compensatory strategies.
Method
Database/Information Sources
The majority of the information on the evidence-based practices (EBPs) for traumatic brain injuries (TBIs) were drawn from The George Washington University’s Himmelfarb Library Subject Database. More specifically, the articles were found within the ERIC (EBSCO) and Psych INFO 1887-Current databases underneath the Speech and Hearing specific page for core resources in the Science and Engineering Database.
Key Search Terms
In order to find the explicit topic of focus, each website allowed for a field section to further refine the searched keywords. For this study, keywords such as traumatic brain injury, cerebral vascular injury, memory, cognitive deficits, compensatory strategies, and pharmacological treatment were used to locate the most accurate results. There were no evident results that compared external compensatory strategies to internal compensatory strategies, so studies were looked at individually and then compared against one another. When looking at external compensatory strategies, search terms included memory outcomes of cognitive rehabilitation and compensatory cognitive training assessments for adult TBI patients. For internal compensatory strategies, search terms included pharmacological treatment for TBI in adults and neuropsychological treatment for memory deficits in TBIs. Majority of the studies assessed a range of patient severity, so explicit research of mild to moderately impaired subjects were identified and included in this paper. Additionally, this paper is focusing solely on the adult demographic, the database offered an advanced search option that offered the selection of age groups, of which ‘adolescence’ to ‘very old’ were selected. The mean age of studies reviewed was approximately forty-five years old.
Methodological Quality: Eligibility Criteria & Study Selection
A combination of peer reviewed journal articles, group designs, ABAB single-case designs, repeated measures designs, crossover designs, and systematic reviews/meta-analyses all “focusing on the efficacy of neuropsychological rehabilitation for prospective memory deficits in Acquired Brain Injury (ABI) were used for research in this paper” (Mahan et al., 2017). However, for the purpose of drawing conclusions about the efficacy of the two types of treatments used, the findings of three systematic reviews were used. Carneys systematic review of Effects of Cognitive Rehabilitation on Outcomes for Persons with TBIs, Wheaton’s meta-analysis of Impact of Early Pharmacological Treatment on Cognitive and Behavioral Outcome after TBI in Adults, and Mahan et al., Neuropsychological Rehabilitation for Prospective Memory Deficits as a Consequence of ABI. In all studies, adolescents and adults ranging from ages 17 to 65 were screened for eligibility criteria and were later assessed post-treatment. Selected participants in each study ranged in severity of their TBI diagnosis, however only mild to moderately impaired patient results were included in this paper. In Carney’s study, participants who were not diagnosed with TBI, pediatrics, those who used pharmacological intervention, those who spoke a foreign language, and TBI as a result of alcohol/drug used were excluded. In Wheaton’s study, patients who experienced previous TBIs or had visual, motor, or language impairments prior to the injury, and those enrolled in external compensatory trainings were excluded from the study. In Mahan’s study, participants without primary diagnosis of ABI or TBI, participants with learning disabilities, psychiatric diagnosis, or dementia were excluded for review.
Risk of Bias/IV Threats
In studies where patients received internal rehabilitation, pharmacological treatment was given according to time of injury. On average, less than a week after treatment in order to, “reduce early neurochemical disturbances (Wheaton, 2011). The only problem this study method poses for the internal validity of the population, is that if treatment is administered within hours of a TBI, the severity of the incident and its specific effect on a given patient is difficult to determine. This has the potential to result in a placebo effect of patient reported symptoms and effects, within the study. Also, in Wheaton et al. study, the cross over design posed a threat for a carryover treatment effect within study participants. Additionally, for studied participants affected by encephalitis do not fall into the category of TBI patients, however there are similar symptoms and cognitive declines experienced by both categories. The treatment methods for each can overlap, but the initial cause of deficits can pose a threat to validity of the study.
Designs Summary & Data Collection Process
Study Participants: # of subjects & severity Research Design Used Treatment Administration Outcome
Carney et al. 137 participants
From 12 studies
Mild-moderate TBI
69 received targeted treatments
68 participants in control group Systematic Review: 5 randomized controlled trials; 1 comparative/ relationship study, and 2 follow-up observational study 1. therapist intervention vs. traditional school therapy
2. imagery training, verbal labeling training, no training, and both training
3. computer attention remediation vs. no tx
4. compensatory external aids (notebook, calendars, schedules, timers, etc.)
5. CARC for memory training vs. two control groups (computer control group and no-exposure control group) 1. 8 of the 18 neuropsychological subtests showed treatment effect
2. Imagery group scored higher than verbal group on all verbal tasks. Verbal group scored higher than imagery group on all imagery tasks
3. No treatment effects
4. No treatment effects
5. Treatment effects proven in 5/12 measures
CMRG>CCG in recall
CMRG>CCG>NEGC in memory index
Wheaton et al. 12,932 participants from 22 studies
6472 (female and male) TBI patients treated with a pharmacological agent
6460 control patients Independent groups repeated measures design & independent groups design Treatment vs. control group outcomes of 7 different drug administrations: serotonergic, catecholaminergic, calcium channel blockers, NMDA antagonists, steroids, peptides, and cannabinoids treatments Independent groups repeated measures: those who used catecholaminergic and peptide treatments showed increases in arousal and attention
– Amantadine (dopamine agonist)
– CP-0127 (bradykinin antagonist)
– DDAVP (peptide)
Mahan et al. 11 studies reviewed
199 total participants (ranging across studies reviewed)
18-65 years old, male & female Single case design (7) and group designs (4) Prospective Memory (PM) task rehabilitation for the use of treatment
– Intervention vs. no treatment or intervention
– Content-specific cue prompting Overall improved memory function and task completion in participants who use technological content-cue prompting
In Carney’s meta-analysis of the efficacy of cognitive rehabilitation outcomes for TBI patients, 6 of the reviewed studies were included in this paper. Those included are 6 different randomized controlled trials. In the randomized controlled trials (RCTs), all participants had suffered from a TBI and the group was split into half. Half of the participants acted as the treatment group and received cognitive rehabilitation and the other half acted as the control group. Meaning they received no treatment and were compared to the treatment group to observe effects of changes in symptoms. Of the six studies, three proved treatment effects and three studies included neuropsychological battery tests. Carney et al., looked to see if cognitive rehabilitation improved health outcomes in TBI patients. One treatment methods included restorative and compensatory therapist intervention vs. traditional school therapy (Thomas-Stonell, 1994). Another included imagery training and verbal labelling training specific to verbal task outcome measures vs. a no control group, a group receiving only verbal training, a group only receiving imagery training, and a group that received both (Twum, 1994). Researchers assessed the number of words and colors recalled immediately after practicing mnemonic techniques with the words and colors (1994). A different study looked at restorative and compensatory memory training, comparing those receiving computer and non computer attention remediation to those who did not (Niemann, 1990). Ruff (1989) looked at the use of external aids: computer and video games, notebooks, calendars, schedules and timers, in order to determine their impact on coping skills, health outcomes, and levels independent living. Lastly, Kerner (1985) examined the use of computer memory retraining. The treatment group received computer-assisted cognitive rehabilitation targeting memory retraining (CMRG). There were two comparison groups included; a computer control group (CCG) and a no-exposure control group (NEGC). The computer control group had accessibility to computer graphics to trigger memory recall whereas the no-exposure group had no clues. Treatment time varied from 10 to 96 hours depending on the study and follow-ups were done for two studies at 1 month and 6 months for outcomes. Follow-ups were carried out for two of the six studies, Niemann's and Kerner’s, however Kerner’s research showed treatment effects and Niemann's did not. Two of the studies included in Carney’s analysis showed a, “direct effect of compensatory cognitive devices (notebooks, wrist watch alarms, programmed reminder devices) on the reduction of everyday memory failures for persons with TBI” (Carney et al., 1999). Another RCT included, “provides evidence that cognitive rehabilitation reduces anxiety and improves self-concept and interpersonal relationships for persons with TBI (1999). This meta-analysis is comprised of RCTs so the level of evidence is classified as 1a/1b. Majority of the outcomes for this review proved inconclusive or have no treatment effects, further supporting the claim that additional research on the efficacy of external compensatory strategies is required and cannot be proven better or more effective than internal compensatory strategies.
The review by Wheaton et al., examined two different research designs to determine the efficacy of pharmacological treatment. Inclusive of an independent groups repeated measures design and an independent groups design (Wheaton et al., 2009). Both research design’s level of evidence are classified as 1b, because they include randomized clinical trials, however the first design is assessed on two different occasions, whereas the second is not. The average age of participants in this data was 33 years old, which researchers noted is conclusive with the statistics that prove younger individuals are more likely to acquire a TBI (2009). There was a significant information pharmacological treatment for TBI patients, however for the purpose of this paper only those who effect memory and/or cognition are included. Two treatment methods proved effective. In a single independent groups repeated measures design, researchers assessed the effects of the dopamine agonist amantadine (also known as Symmetrel) at a dosage of 400 mg/d that was administered within 3 days of a severe TBI and found that this dosage prompted a large improvement in patient’s arousal levels (2009). Secondly, researchers examined the effects two peptide treatments, bradykinin antagonist CP-0127 and DDAVP. Both were tested in by independent groups repeated measurers and proved to positively impact arousal, attention, and memory of those impacted by TBIs (2009). Although a small percentage of the pharmacological treatments proved ineffective, those who did show positive outcomes help support the claim that they can be useful in treatment plans for patients suffering from TBIs.
Lastly, the systematic review by Mahan et al., assessed the effects of external compensatory strategies used for memory recall. There were 9 reviewed studies; A combination of groups designs and single case designs. Both of which fall under 3.2 and 3.3 levels of evidence. In all nine studies, participants either received content-specific cues via the use of electronic devices or they did not. Cues were prompted through smartphones, Google Calendar functions/reminders, voice memos, paging systems, personal digital assistants (PDAs), and assistive television prompts. Three papers proved that a that using a content- prompting paging system could be beneficial in reducing prospective memory (PM) deficits in individuals with TBI (Mahan et al., 2017). Lannin et al. showed that PDA devices with an alerting function help facilitate memory functioning better than non-electronic memory aids (2017). In a more modern study, researchers Lemoncello, Sohlber, Fickas, & Prideaux, looked at assistive television prompts, as it proved to be an effective compensatory strategy for PM functions in TBI adults (2011). Because television plays such a prominent role in the daily lives of today’s adults, hours spent watching television have increased exponentially over the years, it is a good way to project a message that has a high percentage of being seen. Whereas, a non-electronic prompt such as a written note may be overlooked. Additionally, significant increases in task completion and punctuality were shown as a result of smartphone use for digital calendar alerts (Ferguson et al., 2015). Researchers looked at the cellphones’ ability to deliver set alerts of content-specific prompts at certain times each day and the effect it has on task completion. Lastly, the use of voice organizer prompts for message-passing tasks, such as “tell you brother this” and domestic tasks, such as “don’t forget to run the dishwasher” were increased by all participants (Van Den Broek et al., 2000). This meta-analysis of external compensatory strategies for memory, specifically using technology for task prompting proved very effective.
DISCUSSION
Given the information provided by the three different systematic reviews, the level of evidence for this paper’s contention is ranked very high. Although, the reviews are compromised by various research designs, the evidence is explicitly analyzed for content-specific information. The research designs that proved ineffective were briefly explained in methodology, and in reasons for why the information is either disregarded or not strong enough to stand as sole evidence for a conclusion. For that reason, this review would fall under a 1st level of evidence category. There is a combined total of 45 reviewed studies that are used to draw conclusions of the efficacy of treatment methods for memory restoration TBI patients.
The strength of the articles varies, based on number of participants and duration of the study, however those included in this paper are the most credible of those presented. Some of the strength of these articles is that they provide a clear understanding of what is being tested, internal vs. external strategies, and the effects they have in cases of prevalent TBIs. However, what is found to be the weakest parts of the articles, is that very few note specific impacts that treatment has on memory, and more specifically the impacts treatment has of speech modalities and verbal recall. Based on the information provided, sound conclusions can be made, however research findings could be further refined for the benefit of various stakeholders in the TBI population. Although there were few common findings across the different articles, all addressed the prevalence of cognitive and memory functions in adults suffering from TBIs. Researchers acknowledged that it is one of the main reported symptoms of a head injury and is proven most important when rehabilitating the patient’s daily functioning. Another commonality across studies supported the claim that TBI is the leading cause of death and disability in young adults in the United States (CDC, 2006). This shows how important it is for specialists to be trained the effective treatment mechanisms and target areas to address in TBI patients. This is important for sports coaches, school teachers, parents or guardians, SLPs, physical therapists, primary care physicians, and neurologists. This research further expands the conversation of what can be done to accurately and effectively address cognitive deficits in TBI patients and produce a more comprehensive plan of action for patient IEPs. Because two meta-analyses solely looked at external compensatory strategies for memory function, and one looked at internal compensatory strategies, there was no overlaps between findings. The studies on internal strategies only looked at pharmacological treatment and its effects, whereas the contrasting studies only looked at types of external strategies and its efficacy in symptom reduction in memory abilities of TBI patients. Because all studies analyzed were drawn from different meta-analyses, it is likely that the evidence is published based on its significance.
All studies included were previously screened for validity and effect size before being included in each journal. This minimizes the likelihood of threats to validity/credibility of the findings however it significantly increases the reliability. Credibility is achieved because of the extensive analyses of the scientific researchers. They note where problem statistics arise and gaps within findings, and either highlight this fault or do not include in their publication. Reliability is increased because if data supports the conclusion that something is effective vs. ineffective, and there is sufficient information to support a claim, the likelihood of another researcher following the defined steps and achieving the same results is significantly higher. For example, reliability was determined through the use of effect size in one analysis (Wheaton et al., 2009). Their method of ranking was comprised of a mean of effect size based on the sample size and methodological quality of each independent study. The calculated general means were averaged, scaled and rated by two individuals to eliminate bias, insufficiencies, and later determine which studies prove valid and which do not. In comparison, in the review by Mahan et al., the researchers based their criteria for study findings on a scale. It included 27 different items regarding credibility and validity of sample sizes, populations, treatment methods, duration etc., and individually rated each study on whether or not criterion was met (2017). Because the combined populations of each group of treatment strategies is so large, it can be concluded that findings can be generalized to bigger populations. More so, external compensatory strategies than internal. The evidence supporting the efficacy of the use of programs and devices to yield memory recall, is abundant and strong. The prevalence of success stories and use in the healthcare population help the data’s significance. Whereas, the use of pharmacological strategies for memory recall falls short in supportive research. That is because it is not as commonly practiced, and its use is not specific enough to the cognitive rehabilitation of TBI patients. If the treatment goal for a patient is increased daily functionality, a reduction in inflammatory mechanisms of the cerebrum are not as accessible to a general population. There is not enough research to prove its efficacy, which results in not many healthcare professionals becoming well-versed in its uses, which results in very few people administering or using these strategies. Although research does show its usefulness, in comparison to external compensatory strategies, the direction of “at-home remediation” does not align with the findings of pharmacological administration for restoring memory capabilities in TBI patients. Based on the findings of all reviewed analysis, it can be concluded that further research is necessary for both strategies. Evidence of improvements of memory in TBI patients using external compensatory strategies is significantly stronger than those who used internal compensatory strategies. However, more specific studies should be done to target the brain areas that control memory that can be impacted by TBIs and how remediation can be applied. This is a more direct method of treatment, that attacks the problem and solves it directly, whereas external strategies work with the environment to compensate for deficits. In the future, a combination of these two strategies is likely to show the most effective and significant increase in performance and functionality of patients suffering from a TBI. In conclusion, a question for the future includes the outcome of combining the effects of internal and external compensatory strategies and the simultaneous impact they two have on a TBI patient’s quality of life for the duration of their existence.