Stroke rehabilitation reaches a threshold
- PMID: 18769588
- PMCID: PMC2527783
- DOI: 10.1371/journal.pcbi.1000133
Stroke rehabilitation reaches a threshold
Abstract
Motor training with the upper limb affected by stroke partially reverses the loss of cortical representation after lesion and has been proposed to increase spontaneous arm use. Moreover, repeated attempts to use the affected hand in daily activities create a form of practice that can potentially lead to further improvement in motor performance. We thus hypothesized that if motor retraining after stroke increases spontaneous arm use sufficiently, then the patient will enter a virtuous circle in which spontaneous arm use and motor performance reinforce each other. In contrast, if the dose of therapy is not sufficient to bring spontaneous use above threshold, then performance will not increase and the patient will further develop compensatory strategies with the less affected hand. To refine this hypothesis, we developed a computational model of bilateral hand use in arm reaching to study the interactions between adaptive decision making and motor relearning after motor cortex lesion. The model contains a left and a right motor cortex, each controlling the opposite arm, and a single action choice module. The action choice module learns, via reinforcement learning, the value of using each arm for reaching in specific directions. Each motor cortex uses a neural population code to specify the initial direction along which the contralateral hand moves towards a target. The motor cortex learns to minimize directional errors and to maximize neuronal activity for each movement. The derived learning rule accounts for the reversal of the loss of cortical representation after rehabilitation and the increase of this loss after stroke with insufficient rehabilitation. Further, our model exhibits nonlinear and bistable behavior: if natural recovery, motor training, or both, brings performance above a certain threshold, then training can be stopped, as the repeated spontaneous arm use provides a form of motor learning that further bootstraps performance and spontaneous use. Below this threshold, motor training is "in vain": there is little spontaneous arm use after training, the model exhibits learned nonuse, and compensatory movements with the less affected hand are reinforced. By exploring the nonlinear dynamics of stroke recovery using a biologically plausible neural model that accounts for reversal of the loss of motor cortex representation following rehabilitation or the lack thereof, respectively, we can explain previously hard to reconcile data on spontaneous arm use in stroke recovery. Further, our threshold prediction could be tested with an adaptive train-wait-train paradigm: if spontaneous arm use has increased in the "wait" period, then the threshold has been reached, and rehabilitation can be stopped. If spontaneous arm use is still low or has decreased, then another bout of rehabilitation is to be provided.
Conflict of interest statement
The authors have declared that no competing interests exist.
Figures
![Figure 1](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g001.gif)
![Figure 2](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g002.gif)
![Figure 3](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g003.gif)
![Figure 4](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g004.gif)
![Figure 5](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g005.gif)
![Figure 6](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g006.gif)
![Figure 7](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g007.gif)
![Figure 8](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g008.gif)
![Figure 9](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g009.gif)
![Figure 10](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/2527783/bin/pcbi.1000133.g010.gif)
Similar articles
-
Maladaptive plasticity for motor recovery after stroke: mechanisms and approaches.Neural Plast. 2012;2012:359728. doi: 10.1155/2012/359728. Epub 2012 Jun 26. Neural Plast. 2012. PMID: 22792492 Free PMC article. Review.
-
A functional threshold for long-term use of hand and arm function can be determined: predictions from a computational model and supporting data from the Extremity Constraint-Induced Therapy Evaluation (EXCITE) Trial.Phys Ther. 2009 Dec;89(12):1327-36. doi: 10.2522/ptj.20080402. Epub 2009 Oct 1. Phys Ther. 2009. PMID: 19797304 Free PMC article.
-
Motor network changes associated with successful motor skill relearning after acute ischemic stroke: a longitudinal functional magnetic resonance imaging study.Neurorehabil Neural Repair. 2009 Mar-Apr;23(3):295-304. doi: 10.1177/1545968308322840. Epub 2008 Nov 4. Neurorehabil Neural Repair. 2009. PMID: 18984831
-
Construction of efficacious gait and upper limb functional interventions based on brain plasticity evidence and model-based measures for stroke patients.ScientificWorldJournal. 2007 Dec 20;7:2031-45. doi: 10.1100/tsw.2007.299. ScientificWorldJournal. 2007. PMID: 18167618 Free PMC article.
-
Neural plasticity and bilateral movements: A rehabilitation approach for chronic stroke.Prog Neurobiol. 2005 Apr;75(5):309-20. doi: 10.1016/j.pneurobio.2005.04.001. Prog Neurobiol. 2005. PMID: 15885874 Review.
Cited by
-
Upper-Limb Functional Recovery in Chronic Stroke Patients after COVID-19-Interrupted Rehabilitation: An Observational Study.J Clin Med. 2024 Apr 11;13(8):2212. doi: 10.3390/jcm13082212. J Clin Med. 2024. PMID: 38673485 Free PMC article.
-
NSF DARE-Transforming modeling in neurorehabilitation: Four threads for catalyzing progress.J Neuroeng Rehabil. 2024 Apr 3;21(1):46. doi: 10.1186/s12984-024-01324-x. J Neuroeng Rehabil. 2024. PMID: 38570842 Free PMC article. Review.
-
Gamified exercise for the distal upper extremity in people with post-stroke hemiparesis: feasibility study on subjective perspectives during daily continuous training.Ann Med. 2024 Dec;56(1):2306905. doi: 10.1080/07853890.2024.2306905. Epub 2024 Jan 31. Ann Med. 2024. PMID: 38294958 Free PMC article.
-
The Evolution of Hand Proprioceptive and Motor Impairments in the Sub-Acute Phase After Stroke.Neurorehabil Neural Repair. 2023 Dec;37(11-12):823-836. doi: 10.1177/15459683231207355. Epub 2023 Nov 13. Neurorehabil Neural Repair. 2023. PMID: 37953595 Free PMC article.
-
Alterations in the preferred direction of individual arm muscle activation after stroke.Front Neurol. 2023 Sep 22;14:1280276. doi: 10.3389/fneur.2023.1280276. eCollection 2023. Front Neurol. 2023. PMID: 37808491 Free PMC article.
References
-
- Nakayama H, Jorgensen HS, Raaschou HO, Olsen TS. Compensation in recovery of upper extremity function after stroke: the Copenhagen Stroke Study. Arch Phys Med Rehabil. 1994;75:852–857. - PubMed
-
- Duncan PW, Wallace D, Lai SM, Johnson D, Embretson S, et al. The stroke impact scale version 2.0. Evaluation of reliability, validity, and sensitivity to change. Stroke. 1999;30:2131–2140. - PubMed
-
- Wolf SL, Winstein CJ, Miller JP, Taub E, Uswatte G, et al. Effect of constraint-induced movement therapy on upper extremity function 3 to 9 months after stroke: the EXCITE randomized clinical trial. JAMA. 2006;296:2095–2104. - PubMed
-
- Winstein CJ, Rose DK, Tan SM, Lewthwaite R, Chui HC, et al. A randomized controlled comparison of upper-extremity rehabilitation strategies in acute stroke: a pilot study of immediate and long-term outcomes. Arch Phys Med Rehabil. 2004;85:620–628. - PubMed
Publication types
MeSH terms
Grants and funding
LinkOut - more resources
Full Text Sources
Medical