The role of physical exercise in cognitive recovery after traumatic brain injury: A systematic review.
There is a growing body of evidence revealing exercise-induced effects on brain structure and cognitive function across the lifespan. Animal models of traumatic brain injury also suggest exercise is capable of modulating not only the pathophysiological changes following trauma but also the associated cognitive deficits.



To evaluate the effect of physical exercise on cognitive impairment following traumatic brain injury in humans.



A systematic search of the PubMed database was performed using the search terms "cognition" and "executive function, memory or attention", "traumatic brain injury" and "physical exercise". Adult human traumatic brain injury studies that assessed cognitive function as an outcome measure (primary or secondary) and used physical exercise as a treatment (single or combined) were assessed by two independent reviewers. Data was extracted under the guidance of the population intervention comparison outcome framework wherein, characteristics of included studies (exercise duration, intensity, combined or single intervention, control groups and cognitive measures) were collected, after which, methodological quality (Cochrane criteria) was assessed.



A total of 240 citations were identified, but only 6 met our inclusion criteria (3 from search records, 3 from reference lists. Only a small number of studies have evaluated the effect of exercise on cognition following traumatic brain injury in humans, and of those, assessment of efficacy is difficult due to low methodological strength and a high risk of different types of bias.



Evidence of an effect of physical exercise on cognitive recovery suggests further studies should explore this treatment option with greater methodological approaches. Recommendations to reduce risk of bias and methodological shortfalls are discussed and include stricter inclusion criteria to create homogenous groups and larger patient pools, more rigorous cognitive assessments and the study and reporting of additional and combined rehabilitation techniques.
The Guttmann University Institute for Neurorehabilitation, Universitat Autónoma de Barcelona, Badalona, Spain.|Departament de Psicobiologia i Ciéncies de la Salut, Institut de Neurociéncies, Universitat Autónoma de Barcelona, Bellaterra, Spain.
Timothy
T
Morris
Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.|Department of Physical Therapy, University of Miami, Miller School of Medicine, Miami, USA.
Joyce
J
Gomes Osman
The Guttmann University Institute for Neurorehabilitation, Universitat Autónoma de Barcelona, Badalona, Spain.
Jose Maria
JM
Tormos Muñoz
Departament de Psicobiologia i Ciéncies de la Salut, Institut de Neurociéncies, Universitat Autónoma de Barcelona, Bellaterra, Spain.
David
D
Costa Miserachs
Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Alvaro
A
Pascual Leone
D000818:Animals; D000070642:Brain Injuries, Traumatic / Q000150:complications*; D003072:Cognition Disorders / Q000209:etiology* / Q000534:rehabilitation*; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans
Traumatic brain injury; cognition; physical exercise; rehabilitation