Background: Cognitive impairments as sequelae of brain injury are common and can negatively affect activities of everyday life, participation and quality of life. Thus, finding ways to reduce cognitive impairments and ameliorate their negative impact on everyday life is an important focus of research. Aim: The aim of this pilot study was to analyse the effects of a combination of guided mindfulness and aerobic exercise on cognitive ability and mental fatigue in patients with acquired brain injury (ABI). Design: Pilot study, with a before-after design. Setting: Outpatient. Population: Twenty-one patients suffering from ABI, former patients of three rehabilitation medicine departments. Methods: The intervention comprised a structured combination of guided mindfulness program and outdoor walking, three times/week for 12 weeks. The outcome measures included assessment of information processing speed, working memory, oxygen uptake and self-reported mental fatigue. Results: The main results showed improvements in cognitive abilities related to information processing speed, perceived mental fatigue and physical capacity. Conclusions: A combination of mindfulness and physical activity can increase information processing speed and ameliorate mental fatigue. Further studies are needed to confirm our findings. Clinical Rehabilitation Impact: The combination of guided mindfulness and physical activity shows promise as a treatment modality in rehabilitation of impaired information processing speed and mental fatigue following ABI.
Two of the most common cognitive consequences of acquired brain injury (ABI) are impaired working memory and impaired information processing speed [
In addition, persons with ABI, taken as a group, have lower levels of aerobic capacity compared with the normal population [
Mindfulness can be defined as skills that aim to direct ones attention to the present moment experience―and adopting an attitude of acceptance regarding that experience [
Thus, there is some evidence that mindfulness and physical activity separately has a beneficial effect on cognition, but there is very limited knowledge concerning the effects of a combination of mindfulness and physical activity in patients with ABI.
The aim of this pilot study was to analyse effects of a combination of guided mindfulness and aerobic exercise on cognitive ability and mental fatigue in patients with ABI.
The inclusion criteria were: a diagnosed non-progressive ABI; age > 18 years; >6 months after occurrence of brain lesion; a subjective reported cognitive impairment; a cognitive status equivalent to Rancho Los Amigo Scale [
Exclusion criteria were: aphasia; neuropsychiatric diagnoses; depression as clinically assessed by a neuropsychologist; simultaneous participation in any other type of organized cognitive training.
Sample size was determined based on a power analysis on a former study on patients with ABI who participated in another rehabilitation intervention (working memory training) were partly the same neuropsychological tests were used [
The intervention comprised a structured combination of mindfulness and outdoor walking in a forest or pathway with surrounding trees in proximity to each of the respective rehabilitation departments, three times/week for 12 weeks. Each session started with walking, 10 minutes at exertion level 11 (Borgs Rating of Perceived Exertion-light) [
The outcome measures comprised cognitive assessment tests for evaluation of information processing speed and working memory, an ergometer test and self-reported mental fatigue. Two neuropsychologists, who were not engaged in any part of the intervention, did the cognitive assessments before and after 12 weeks training. The tests were administered in the same order and in the same way for each participant at every assessment occasion. One physiotherapist did all the ergometer tests before and after 12 weeks of training.
The Åstrand test is a submaximal evaluation of oxygen uptake [
Neuropsychological tests were selected to cover aspects of information processing speed, attention and working memory, cognitive functions often impaired in the brain injured population [
Paced Auditory Serial Attention Test 2.4 (PASAT) [
Block repetition, forward and backward, from WMS-III [
Listening span task [
Digit Symbol Coding (DSC) from WAIS-IV [
Trail Making Test (TMT) from D-KEFS [
DLS reading speed test (DLS) [
The participants filled in Mental Fatigue Scale (MFS) [
Data were analyzed using IBM SPSS Statistics 21. Descriptive results from the assessments were presented as the median and IQR. To compare differences in the results before and after the intervention, non-parametric statistics (Wilcoxon matched-pair signed ranks test) was used because of the limited number of participants and a skewed distribution of data. Effect size for each analysis was calculated using Rosenthal’s r. For correlation analyses, Spearman’s rank correlation test was used. The accepted level of significance was p < 0.05.
No medical or other risks related to participation in the study could be identified. Written informed consent was obtained from the participants before the study. The study was approved by the local research ethics committee (2015/168-319).
This study included 21 participants with ABI. Characteristics of the participants, such as gender and diagnoses, is described in
As the aim of the study was to look at potential positive cognitive effects from physical training, it was important to check how physical capacity did change with intervention. Before the intervention, the median oxygen uptake expressed as ml of O2 per kg body weight per minute was 28.0 ml (IQR, 23.0 - 35.0 ml); at follow-up, the median was 35.0 ml (IQR, 28.0 - 45.0 ml, p < 0.001), indicating that the intervention had had a positive effect on aerobic capacity.
Results of the neuropsychological tests TMT I-IV, DLS and DSC showed an
n | % | ||
---|---|---|---|
Diagnoses | |||
Stroke Traumatic brain injury Encephalitis/Meningitis Other | 9 6 4 2 | 43 29 19 9 | |
Gender | |||
Men Women | 9 12 | 43 57 |
Before median (IQR) | After median, (IQR) | Effect size | p value | |
---|---|---|---|---|
TMT I (seconds) | 28 (23.5 - 33.5) | 23(18.5 - 28) | 0.49 | 0.001 |
TMT II (seconds) | 39 (34.5 - 58.5) | 36 (28.5 - 45) | 0.35 | 0.022 |
TMT III (seconds) | 38 (33.5 - 58.5) | 33 (24.5 - 48.5) | 0.43 | 0.005 |
TMT IV (seconds) | 103 (85.5 - 139) | 84 (68 - 112.5) | 0.32 | 0.035 |
DLS (number of words) | 17 (14 - 21.5) | 21 (17.5 - 29.5) | 0.43 | 0.006 |
DSC (number of symbols) | 49 (41 - 59) | 54 (49 - 65) | 0.43 | 0.006 |
PASAT (number of words) | 35 (28 - 45) | 40 (31 - 49) | 0.29 | 0.077, n.s. |
Block repetition (number of blocks) | 13 (11 - 16) | 14 (12 - 16) | 0.15 | 0.324, n.s. |
Listening span (number of words) | 26 (19 - 28) | 25 (19 - 30) | 0.15 | 0.340, n.s. |
Wilcoxon matched pairs test was used for comparison between results from before the intervention versus after 12 weeks of intervention. Effects sizes was calculated using Rosenthal’s r. TMT I-IV: Trail Making Test parts I-IV. DLS: DLS reading speed test. DSC: Digit Symbol Coding. PASAT: Paced Auditory Serial Attention Test.
Before median (IQR) | After median, (IQR) | Effect size | p value | |
---|---|---|---|---|
MFS | 15.0 (9.8 - 19.0) | 13.0 (8.8 - 18.0) | 0.32 | 0.040 |
Wilcoxon matched pairs test was used for comparison between results from before the intervention versus after 12 weeks of intervention. Effects sizes was calculated using Rosenthals r. MFS: Mental Fatigue Scale.
improvement after intervention (
Perceived mental fatigue, as measured by MFS, was significantly reduced (
To investigate if the changes in those neuropsychological test with significant results after training were correlated to the change in perceived mental fatigue, correlation analyses were made using the differences in results between pre- and post-test results. Significant correlations were found between the difference in patients’ perceived mental fatigue and the difference in DSC (r = 0.549, p < 0.05) and TMT-IV (r = 0.479, p < 0.05) respectively.
The aim of this pilot study was to analyse the effects of an intervention including guided mindfulness sessions combined with aerobic exercise on cognitive ability and mental fatigue. The results showed improvements in MFS, as well as the neuropsychological tests TMTI-IV, DLS and DSC. DSC is part of the processing speed index in WAIS, and as such it is commonly used to assess information processing speed [
Information processing speed and working memory are related [
Kohl et al. [
Perceived results might be secondary to reduced stress, which should be further studied. Previous research on healthy individuals has shown that mindfulness can affect neural networks considered important in activation of stress [
If mindfulness affects the neural networks also after a brain injury, then one of the benefits of adding aerobic exercise might be to facilitate this effect, as aerobic exercise has been shown to enhance neuroplasticity [
Kaplan proposed a model where information processing, stress and (attentional) fatigue were related to each other [
Well-established, valid and reliable outcome measurements were chosen for this study to optimize the quality and trustworthiness. Further strengths of the study were that all assessments were performed by two neuropsychologists and one physiotherapist, all with long experience of assessments following ABI and who were not engaged in the intervention. To assure that the intervention was equivalent in all three locations, it was based on a manual and led by three physiotherapists with the same education in mindfulness.
This study was a pilot study and therefore the sample is small, it is intended to serve as a basis for further studies with larger sample sizes to confirm the results and discussion on the underlying factors in relation to results. Larger sample sizes are also a necessity to be able to form a control group. Another reason to conduct a pilot study is to test feasibility of the intervention. The compliance to the intervention was very good. Despite the relatively intense program, the participants did not complain of fatigue due to the activity; on the contrary, perceived mental fatigue was found to be reduced and the participants expressed that they intended to continue the exercises after the 12 weeks.
Because functional recovery has been shown to be mostly completed after approximately 3 months [
Impaired information processing speed and mental fatigue are common following ABI [
Since the combination of mindfulness and aerobic exercise (with the potential addition of nature) seems to increase information processing speed and ameliorate mental fatigue, this raises the question of why this is so. How can we understand the possible underlying mechanism? A hypothesis from this study is that the effect of the intervention on information processing speed and mental fatigue is secondary to an effect on stress. Further studies are needed to confirm presented results and to test this hypothesis.
The authors would like to thank the participants of the intervention. The authors would also like to thank the neuropsychologist Kit Schwerdt and occupational therapist Margareta Fridén for data collection, and the physiotherapists who led the intervention; Eva Lilliecreutz, Beatrice Felixson and Caroline Leon. The study was supported financially by Futurum, Academy for Health and Care (grant numbers Futurum-519331, Futurum-608761) and the Medical Research Council of Southeast Sweden (grant number FORSS-559471).
The authors have no conflicts of interest to disclose.
Hellgren, L., Lundqvist, A., Börsbo, B., Levi, R. and Samuelsson, K. (2019) Mindfulness and Aerobic Exercise as an Intervention for Cognitive Dysfunction Following an Acquired Brain Injury: A Pilot Study. Open Journal of Therapy and Rehabilitation, 7, 12-24. https://doi.org/10.4236/ojtr.2019.71002