Implications of basic science research for brain injury rehabilitation: a focus on intact learning mechanisms

Visual Priming Enhances the Effects of Nonspatial Cognitive Rehabilitation Training on Spatial Learning After Experimental Traumatic Brain Injury

Previous work demonstrates that spatial (explicit) and nonspatial (implicit) elements of place learning in the Morris water maze (MWM) task can be dissociated and examined in the context of experimental traumatic brain injury (TBI). Providing nonspatial cognitive training (CT) after injury can improve place learning compared with untrained controls. In the present study, we hypothesized that brief exposure to extra-maze cues, in conjunction with CT, may further improve MWM performance and extra-maze cue utilization compared with CT alone. Adult male Sprague-Dawley rats (n = 66) received controlled cortical impact (CCI) injury or sham surgery. Beginning day 8 postsurgery, CCI and sham rats received 6 days of no training (NT) or CT with/without brief, noncontextualized exposure to extra-maze cues (BE and CT, respectively). Acquisition (days 14-18), visible platform (VP; day 19), carryover (CO; days 20-26), and periodic probe trials were performed. Platform latencies, peripheral and target zone time allocation, and search strategies were assessed. CCI/BE rats had shorter acquisition trial latencies than CCI/NT (P < .001) and tended to have shorter latencies than CCI/CT rats (P < .10). Both BE and CT reduced peripheral zone swimming for CCI rats versus CCI/NT. CCI/BE animals increased spatial swim strategies from day 14 to day 18 relative to CCI/CT and showed similar swim strategy selection to the Sham/NT group. These data suggest that visual priming improves initial place learning in the MWM. These results support the visual priming response as another clinically relevant experimental rehabilitation construct, to use when assessing injury and treatment effects of behavioral and pharmacological therapies on cognition after TBI.

Flow Experience during Attentional Training Improves Cognitive Functions in Patients with Traumatic Brain Injury: An Exploratory Case Study

Objective/Background

Flow is the holistic experience that occurs when an individual acts with total involvement. The objective of this study was to examine the effects of attention training that induces flow experience for patients with attention-deficit disorder after traumatic brain injury (TBI).

Methods

A two-patient case report with a within-subject AB design was conducted. Two patients with attention deficit after TBI were recruited for attention training. Two types of video game tasks for attention training were created, one inducing flow (flow task) and the other not (control task). Patient A performed the flow task for 14 days after receiving general occupational therapy (OT) for 11 days. Patient B performed the flow task for 15 days after performing the control task for 10 days. We examined training effects using neuropsychological tests. The Flow State Scale for Occupational Tasks was administered to identify the patient's flow state. To evaluate the training effect, we used visual analysis, the two-standard deviation band method, and effect-size analyses.

Results

Both Patient A and Patient B showed improvement on the Continuous Performance Test, Symbol Digit Modalities Test, and Moss Attention Rating Scale after the flow task. Patient B also showed improvement on the Trail Making Test.

Conclusion

The results for Patient A suggested that the flow task was more effective than general OT for improving attention deficits. Moreover, the results for Patient B suggested that the flow task was more effective than the control task. Attention training inducing flow experience may thus facilitate improvement of attention.

Implicit memory influences on metamemory during verbal learning after traumatic brain injury

PURPOSE

Prior research has shown that individuals with traumatic brain injury (TBI) may be overconfident in their judgments of learning (JOLs; online measures of self-monitoring of learning and memory). JOLs had been presumed to be driven by explicit processes, but recent research has also revealed implicit memory involvement. Given that implicit learning mechanisms are often intact in those with TBI, the purpose of this study was to investigate whether priming and antipriming of immediate and delayed JOLs in individuals with TBI might affect their overconfidence.

METHOD

A standard 3-field masked priming paradigm was combined with a paired-associate learning task with JOLs and administered to individuals with TBI and matched controls (18 per group). In each trial, a subliminal masked stimulus was immediately followed by supraliminal presentation of a word pair for study; participants also made immediate and delayed JOLs, with cued-recall testing 10 min after study and judgment.

RESULTS

Antipriming significantly lowered JOLs and overconfidence for both groups, whereas delaying JOLs significantly improved recall for both groups.

CONCLUSIONS

The results suggest that JOLs may be influenced by subliminal implicit memory. Clinical implications include the possible use of antipriming to reduce overconfidence after brain injury and delaying JOLs to improve recall.

Developing a clinically relevant model of cognitive training after experimental traumatic brain injury

BACKGROUND

Following traumatic brain injury (TBI), clinical cognitive training paradigms harness implicit and explicit learning and memory systems to improve function; however, these systems are differentially affected by TBI, highlighting the need for an experimental TBI model that can test efficacy of cognitive training approaches.

OBJECTIVES

To develop a clinically relevant experimental cognitive training model using the Morris water maze (MWM) wherein training on implicitly learned task components was provided to improve behavioral performance post-TBI.

METHODS

Eighty-one adult male rats were divided by injury status (controlled cortical impact [CCI]/Sham), non-spatial cognitive training (CogTrained/No-CogTrained), and extra-maze cues (Cued/Non-Cued) during MWM testing. Platform latencies, thigmotaxis, and search strategies were assessed during MWM trials.

RESULTS

Cognitive training was associated with improved platform latencies, reduced thigmotaxis, and more effective search strategy use for Sham and CCI rats. In the Cued and Non-Cued MWM paradigm, there were no differences between CCI/CogTrained and Sham/No-CogTrained groups. During novel testing conditions, CogTrained groups applied implicitly learned knowledge/skills; however, sham-cued CogTrained/rats better incorporated extramaze cues into their search strategy than the CCI-Cued group. Cognitive training had no effects on contusion size or hippocampal cell survival.

CONCLUSIONS

The results provide evidence that CCI-CogTrained rats that learned the nonspatial components of the MWM task applied these skills during multiple conditions of the place-learning task, thereby mitigating cognitive deficits typically associated with this injury model. The results show that a systematic application of clinically relevant constructs associated with cognitive training paradigms can be used with experimental TBI to affect place learning.

Revisiting the neurofunctional approach: conceptualizing the core components for the rehabilitation of everyday living skills

BACKGROUND

Introduced in the 1980s, the neurofunctional approach (NFA) is one of the few interventions designed primarily for clients with severe deficits following traumatic brain injury (TBI). Specifically the NFA was intended for those individuals who were limited in their ability to solve novel problems or generalize skills from one setting to another and whose lack of insight limited their engagement in the rehabilitative process. DESCRIPTION OF THE APPROACH: The NFA is a client-centred, goal-driven approach that incorporates the principles of skill learning and promotes the development of routines and competencies in practical activities required for everyday living. Programmes based on the NFA are developed specifically to meet each client's unique needs, using a range of evidence-based interventions. RECENT EVIDENCE: Recently the NFA has been found to be more effective than cognitive-retraining for some individuals with moderate-to-severe TBI who have deficits in activities of daily living. This paper aims to define the core features of the NFA, outline the theoretical basis on which it is founded and consider implications of the findings for rehabilitation after TBI in general. The NFA is highly relevant for clients living in the community who require a case manager to direct an integrated, rehabilitation programme or provide structured input for the long-term maintenance of skills.

Non-spatial pre-training in the water maze as a clinically relevant model for evaluating learning and memory in experimental TBI

Explicit and implicit learning and memory networks exist where each network can facilitate or inhibit cognition. Clinical evidence suggests that implicit networks are relatively preserved after traumatic brain injury (TBI). Non-spatial pre-training (NSPT) in the Morris Water Maze (MWM) provides the necessary behavioral components to complete the task, while limiting the formation of spatial maps. Our study utilized NSPT in the MWM to assess implicit and explicit learning and memory system deficits in the controlled cortical impact (CCI) model of TBI. 76 adult male Sprague-Dawley rats were divided: CCI vs. sham surgery, NSPT vs. No-NSPT, and cued vs. non-cued groups. NSPT occurred for 4d prior to surgery (dynamic hidden platform location, extra-maze cues covered, static pool entry point). Acquisition (d14-18), Probe/Visible Platform (d19), and Reversal (d20-21) trials were conducted with or without extra-maze cues. Novel time allocation and search strategy selection metrics were utilized. Results indicated implicit and explicit learning/memory networks are distinguishable in the MWM. In the cued condition, NSPT reduced thigmotaxis, improved place learning, and largely eliminated the apparent injury-induced deficits typically observed between untrained CCI and sham rats. However, among NSPT groups, incorporation of cues into search strategy selection for CCI rats was relatively impaired compared to shams. Non-cued condition performance showed sham/NSPT and CCI/NSPT rats perform similarly, suggesting implicit memory networks are largely intact 2weeks after CCI. Place learning differences between CCI/NSPT and sham/NSPT rats more accurately reflect spatial deficits in our CCI model compared to untrained controls. These data suggest NSPT as a clinically relevant construct for evaluating potential neurorestorative and neuroprotective therapies. These findings also support development of non-spatial cognitive training paradigms for evaluating rehabilitation relevant combination therapies.

Integrating situated learning theory and neuropsychological research to facilitate patient participation and learning in traumatic brain injury rehabilitation patients

PURPOSE

Traumatic brain injury (TBI) constitutes a major health problem throughout the world. Despite interdisciplinary efforts, patients reach varying outcomes in terms of every-day life functioning and quality-of-life. This paper suggests that a situated learning perspective supplemented with evidence from neurophysiologic and neuropsychological research provides a perspective to get a grasp of problems typically encountered in rehabilitation. Applying such a perspective may help to facilitate patient participation and learning during the rehabilitation process by taking their altered abilities into consideration.

METHOD

Qualitative study. Theoretical analysis and synthesis of 'situated learning theory', neuropsychological theory and empirical studies of cognitive and emotional functioning following a TBI collected through interviews with 11 interdisciplinary rehabilitation experts and a field study of two patients at a rehabilitation hospital. The data were analysed from a hermeneutic perspective using N-VIVO 8.

RESULTS/CONCLUSION

Patients with severe TBI pose challenges in terms of being participants in the 'rehabilitation practice community'. Two levels of pedagogical challenges seem to exist: Helping the patient regain or compensate for changed learning abilities and supporting the patient in learning or compensating for lost abilities. This study highlighted six main categories of changed abilities that need to be considered in developing a practice which fosters re-learning: perception, attention, memory, language, physical competencies and emotion/model of behaviour.

Evaluation of technology-assisted learning setups for undertaking assessment and providing intervention to persons with a diagnosis of vegetative state

OBJECTIVE

To evaluate the viability of technology-assisted learning setups for undertaking assessment and providing intervention to persons in vegetative state.

METHOD

Study I investigated whether three persons with a diagnosis of vegetative state could associate eye blinking or hand closure responses with contingent, positive stimulation, thus increasing their frequencies (showing signs of learning). Study II extended the learning process (introducing a new response and new stimuli) for one of the participants of Study I.

RESULTS

Two of the participants of Study I succeeded in increasing their responses, indicating signs of learning. Study II showed that the participant (one of the two succeeding in Study I) acquired a new response to access new stimuli and could alternate this response with the one acquired in Study I.

CONCLUSION

Learning might represent a basic level of knowledge and consciousness. Detecting signs of learning might help modify a previous diagnosis of vegetative state and support intervention/rehabilitation efforts.

Learning as a possible sign of non-reflective consciousness in persons with a diagnosis of vegetative state and pervasive motor impairment

A diagnosis of vegetative state represents a serious predicament, which basically precludes/minimizes rehabilitation perspectives. Reliability of the assessment approach in these situations is of paramount importance, but not easy to achieve. In recent studies, a learning assessment procedure has been suggested as a supplement in the diagnostic process and assessed with eight patients. The procedure involves an ABABCB sequence in which A represents baseline phases with no stimulation available, B intervention phases with stimuli delivered contingently on target responses, and C a control condition. This condition involves stimulation presented non-contingently. The patients' ability to associate responding with environmental stimuli and thus increase such responding during the B phases, and reduce it during the A and C phases, may be considered a sign of learning. Learning might be viewed as representative of forms of concrete knowledge and presumably basic levels of consciousness. Preliminary results indicate that (a) signs of learning may appear in patients with a previous diagnosis of vegetative state and (b) the presence of those signs may require a revision of their diagnostic label and a reappraisal of their rehabilitation perspectives.