Traumatic Brain Injury: Interventions and Treatment
The authors first distinguish between different "levels" of treatment. One may seek to directly improve executive function impairments, perhaps by pharmacological means. A second strategy is to provide devices that can be used to overcome or compensate for these impairments.
The next distinction is between the various levels of testing. One can attempt to measure underlying executive functions themselves (as in the Stroop or WCST paradigms, for example) or can instead measure "functional outcome" - i.e., a more naturalistic level of the patient's ultimate ability to function autonomously.
Cicerone et al. advocate the use of "crossover" experimental designs to investigate the effects of various treatment options. In these techniques, each subject is given either all or some of the available treatments; this serves to reduce variance between subjects and thus increase statistical power.
Unfortunately, current EF rehabilitation often focuses on compensatory techniques, and relies on the clinician to select the appropriate strategy for a given situation. Cicerone et al. note that a prominent feature of executive dysfunction is the failure to self-generate behavior, so in this case the rehabilitation program is simply not addressing this primary type of EF impairment! More ecologically-valid treatments are a particularly promising area of research.
Along these lines, "holistic" rehabilitation programs attempt to address a wide range of behavioral problems simultaneously, including problem-solving, behavioral and emotional regulation, working memory deficits, metacognitive functions (Cicerone et al. include planning, inhibition and self-monitoring under this rubric), and "activation." Each is covered in turn below.
Treatment for Problem-Solving Deficits
Cicerone et al review several prospective, randomized studies problem-solving interventions in patients with TBI or "cerebral insult. In one such study, an experimental group was taught to break down every problem into its constituent subgoals, including training in "problem orientation, problem definition and formulation, generation of alternatives, decision making and solution verification." This group demonstrated substantial gains in "awareness of cognitive deficits, goal-directed ideas, and problem-solving" as compared to a control group that underwent only "memory retraining."
Cicerone et al. also review the effiicacy of "goal-management training," which involves training to "evaluate the current problem state ('What am I doing?') [...] specification of the relevant goals (the 'main task'), and partitioning of the problem-solving process into subgoals (the 'steps')" followed by training to improve retention of these subgoals and to monitor the outcomes of their results. Assessment of this program's efficacy involved patient performance on naturalistic complex tasks (e.g., "room layout"); patients who had undergone 1 hour of goal-management training showed quicker completion time and fewer errors than a control group who had undergone motor skills training.
A third studied reviewed by Cicerone et al. involved around 60 hours of "cognitive-behavioral training in problem-solving skills, a systematic process for analyzing real-life problems, and role-play of real-life examples of problem situations," whereas a control group was trained to "improve cognitive skills and support for coping with emotional reactions and changes after injury." Although both groups improved on some measures, only the experimental group improved on measures of ECF (although this training did not result in gains on more naturalistic measures of functional ouctome, i.e., "community integration").
Working Memory Deficit Intervention
Cicerone et al. review the pharmacological use of bromocriptine (a D2 agonist) on patients with TBI-induced EF impairment, which improved dual but not single task performance. In other words, patients showed better efficiency at completing both tasks simultaneously but not on completing either one individually. This seems to be a specific improviement in executive function.
Behavioral and Emotional Self-Regulation
Two studies involved providing situational cues that would remind EF-impaired TBI patients to reconsider the overall goal of their current task. In one study this involved pre-training on stimulus-response contingencies of the kind "if y, then I'll do x", whereas in the other study an auditory tone was played to remind patients to reconsider their goal.
Cicerone et al briefly review other attempts to improve emotional self-regulation, including anger-management techniques. Unfortunately, Cicerone et al. suggest that emotional self-regulation impairments may be particularly resistant to treatment.
One typical symptom of frontal damage is lack of motivation or drive. Cicerone et al suggest that very few studies have investigated how to address this problem, although simply cuing patients to initiate conversation shows some limited benefit. The pharmacological D2 agonist Bromocriptine also seems to have some benefit for increasing spontaneity.
Cicerone et al. review an attempt to teach one brain damaged patient to "internally verbalize" the patient's current intent or goal. In three stages lasting 2-3 weeks apiece, this verbalization went from overt to completely covert; afterwards, the patient was trained for an additional 12 weeks to apply these strategies to everyday situations. This patient and subsequent patients with the same treatment seemed to show improvement in their inhibitory skills.