Objective metrics for the quantification of neurophysiological, biomechanical and strength changes in patients with spinal cord injury after upper extremity brain-computer interface-based rehabilitation programs
Keywords:
Electroencephalography, grip strength, brain-machine interface, spinal cord injury, neurorehabilitationAbstract
Spinal cord injury (SCI) at the cervical level produces significant motor impairments in the upper extremity (UE), negatively affecting patients’ functional independence. Although conventional therapies can be beneficial in the rehabilitation process, their effectiveness is limited by factors such as disruption of motor communication pathways and the lack of sensorial feedback that the patients can receive. Because of this, brain-computer interfaces (BCI) have emerged as a promising complementary therapeutic option. BCI can decode central nervous system signals to produce visual, sensorial, or motor feedback to promote neuroplasticity mechanisms. Currently, the standard to assess the impact of BCI-based interventions comprises the use of clinical scales and the analysis of the obtained scores. However, these scales involve a subjective component that showcase the need to incorporate objective quantitative metrics to assess the clinical efficacy and effectiveness of the BCI. This narrative review presents different neurophysiological, biomechanical, and strength-related metrics that have been proposed to evaluate changes observed in patients with SCI after completing a BCI-based UE rehabilitation program. Although these metrics show potential as possible biomarkers of recovery, several limitations still need to be addressed, including a lack of standardization in data acquisition and analysis. Despite these constraints, evidence suggests that the use of objective quantitative metrics could provide a more complete and robust characterization of the motor rehabilitation process of the UE after a SCI.
Publication Facts
Reviewer profiles N/A
Author statements
Indexed in
- Editor & editorial board
- profiles
- Academic society
- N/A
To learn about these publication facts, click 
PF is maintained by the Public Knowledge Project
References
Silva NA, Sousa N, Reis RL, Salgado AJ. From basics to clinical: A comprehensive review on spinal cord injury. Prog Neurobiol [Internet]. 2014;114:25–57. https://doi.org/10.1016/j.pneurobio.2013.11.002
Walker JR, Detloff MR. Plasticity in Cervical Motor Circuits following Spinal Cord Injury and Rehabilitation. Biology (Basel) [Internet]. 2021;10. https://doi.org/10.3390/biology10100976
Dengler J, Mehra M, Steeves JD, Curt A, Maier D, Abel R, et al. Evaluation of Functional Independence in Cervical Spinal Cord Injury: Implications for Surgery to Restore Upper Limb Function. J Hand Surg Am [Internet]. 2021;46:621.e1-621.e17. https://doi.org/10.1016/j.jhsa.2020.10.036
Lili L, Sunnerhagen KS, Rekand T, Alt Murphy M. Independence and upper extremity functioning after spinal cord injury: a cross-sectional study. Sci Rep [Internet]. 2023;13:3148. https://doi.org/10.1038/s41598-023-29986-y
Wang TY, Park C, Zhang H, Rahimpour S, Murphy KR, Goodwin CR, et al. Management of Acute Traumatic Spinal Cord Injury: A Review of the Literature. Front Surg [Internet]. 2021;Volume 8-2021. https://doi.org/10.3389/fsurg.2021.698736
Harkema S, Gerasimenko Y, Hodes J, Burdick J, Angeli C, Chen Y, et al. Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: a case study. The Lancet [Internet]. Elsevier; 2011;377:1938–47. https://doi.org/10.1016/S0140-6736(11)60547-3
Daly JJ, Wolpaw JR. Brain-computer interfaces in neurological rehabilitation. Lancet Neurol [Internet]. Elsevier; 2008;7:1032–43. https://doi.org/10.1016/S1474-4422(08)70223-0
Merante A, Zhang Y, Kumar S, Nam CS. Brain–Computer Interfaces for Spinal Cord Injury Rehabilitation. In: Nam CS, editor. Neuroergonomics: Principles and Practice [Internet]. Cham: Springer International Publishing; 2020. p. 315–28. https://doi.org/10.1007/978-3-030-34784-0_16
Lebedev MA, Nicolelis MAL. Brain-Machine Interfaces: From Basic Science to Neuroprostheses and Neurorehabilitation. Physiol Rev [Internet]. American Physiological Society; 2017;97:767–837. https://doi.org/10.1152/physrev.00027.2016
Lili L, S Sunnerhagen K, Rekand T, Alt Murphy M. Associations between upper extremity functioning and kinematics in people with spinal cord injury. J Neuroeng Rehabil. BioMed Central Ltd; 2021;18. https://doi.org/10.1186/s12984-021-00938-9
Itzkovich M, Shefler H, Front L, Gur-Pollack R, Elkayam K, Bluvshtein V, et al. SCIM III (Spinal Cord Independence Measure version III): reliability of assessment by interview and comparison with assessment by observation. Spinal Cord [Internet]. 2018;56:46–51. https://doi.org/10.1038/sc.2017.97
Cuthbert SC, Goodheart GJ. On the reliability and validity of manual muscle testing: a literature review. Chiropr Osteopat [Internet]. 2007;15:4. https://doi.org/10.1186/1746-1340-15-4
Marino RJ, Burns S, Graves DE, Leiby BE, Kirshblum S, Lammertse DP. Upper- and lower-extremity motor recovery after traumatic cervical spinal cord injury: An update from the national spinal cord injury database. Arch Phys Med Rehabil. 2011;92:369–75. https://doi.org/10.1016/j.apmr.2010.09.027
Oleson C V., Marino RJ. Responsiveness and concurrent validity of the revised Capabilities of Upper Extremity-Questionnaire (CUE-Q) in patients with acute tetraplegia. Spinal Cord. Nature Publishing Group; 2014;52:625–8. https://doi.org/10.1038/sc.2014.77
Ofner P, Schwarz A, Pereira J, Wyss D, Wildburger R, Müller-Putz GR. Attempted Arm and Hand Movements can be Decoded from Low-Frequency EEG from Persons with Spinal Cord Injury. Sci Rep. Nature Publishing Group; 2019;9. https://doi.org/10.1038/s41598-019-43594-9
Ajiboye AB, Willett FR, Young DR, Memberg WD, Murphy BA, Miller JP, et al. Restoration of reaching and grasping movements through brain-controlled muscle stimulation in a person with tetraplegia: a proof-of-concept demonstration. The Lancet [Internet]. Elsevier; 2017;389:1821–30. https://doi.org/10.1016/S0140-6736(17)30601-3
Bellitto A, Luca A De, Gamba S, Losio L, Massone A, Casadio M, et al. Clinical, Kinematic and Muscle Assessment of Bilateral Coordinated Upper-Limb Movements Following Cervical Spinal Cord Injury. IEEE Transactions on Neural Systems and Rehabilitation Engineering. 2023;31:3607–18. https://doi.org/10.1109/TNSRE.2023.3309539
Neto FR, Gomes Costa RR, Dorneles JR, Gonçalves CW, Veloso JHCL, Carregaro RL. Handgrip Strength Cutoff Points for Functional Independence and Wheelchair Ability in Men With Spinal Cord Injury. Top Spinal Cord Inj Rehabil [Internet]. 2021;27:60–9. https://doi.org/10.46292/sci20-00040
Nishikawa-Pacher A. Research Questions with PICO: A Universal Mnemonic. Publications. MDPI; 2022;10. https://doi.org/10.3390/publications10030021
Osuagwu BCA, Wallace L, Fraser M, Vuckovic A. Rehabilitation of hand in subacute tetraplegic patients based on brain computer interface and functional electrical stimulation: A randomised pilot study. J Neural Eng. Institute of Physics Publishing; 2016;13. https://doi.org/10.1088/1741-2560/13/6/065002
Trincado-Alonso F, López-Larraz E, Resquín F, Ardanza A, Pérez-Nombela S, Pons JL, et al. A Pilot Study of Brain-Triggered Electrical Stimulation with Visual Feedback in Patients with Incomplete Spinal Cord Injury. J Med Biol Eng. Springer Berlin Heidelberg; 2018;38:790–803. https://doi.org/10.1007/s40846-017-0343-0
Cruccu G, Aminoff MJ, Curio G, Guerit JM, Kakigi R, Mauguiere F, et al. Recommendations for the clinical use of somatosensory-evoked potentials. Clinical Neurophysiology [Internet]. 2008;119:1705–19. https://doi.org/10.1016/j.clinph.2008.03.016
Maudrich T, Hähner S, Kenville R, Ragert P. Somatosensory-Evoked Potentials as a Marker of Functional Neuroplasticity in Athletes: A Systematic Review. Front Physiol [Internet]. 2022;Volume 12-2021. https://doi.org/10.3389/fphys.2021.821605
Curt A, Dietz V. Electrophysiological recordings in patients with spinal cord injury: significance for predicting outcome. Spinal Cord [Internet]. 1999;37:157–65. https://doi.org/10.1038/sj.sc.3100809
Spiess M, Schubert M, Kliesch U, Halder P. Evolution of tibial SSEP after traumatic spinal cord injury: Baseline for clinical trials. Clinical Neurophysiology [Internet]. 2008;119:1051–61. https://doi.org/10.1016/j.clinph.2008.01.021
Wan L, Huang H, Schwab N, Tanner J, Rajan A, Lam NB, et al. From eyes-closed to eyes-open: Role of cholinergic projections in EC-to-EO alpha reactivity revealed by combining EEG and MRI. Hum Brain Mapp [Internet]. John Wiley & Sons, Ltd; 2019;40:566–77. https://doi.org/10.1002/hbm.24395
Boord P, Siddall PJ, Tran Y, Herbert D, Middleton J, Craig A. Electroencephalographic slowing and reduced reactivity in neuropathic pain following spinal cord injury. Spinal Cord [Internet]. 2008;46:118–23. https://doi.org/10.1038/sj.sc.3102077
Barry RJ, Clarke AR, Johnstone SJ, Magee CA, Rushby JA. EEG differences between eyes-closed and eyes-open resting conditions. Clinical Neurophysiology [Internet]. 2007;118:2765–73. https://doi.org/10.1016/j.clinph.2007.07.028
Kumari R, Dybus A, Purcell M, Vučković A. Motor priming to enhance the effect of physical therapy in people with spinal cord injury. Journal of Spinal Cord Medicine. Taylor and Francis Ltd.; 2025;48:312–26. https://doi.org/10.1080/10790268.2024.2317011
Pfurtscheller G, Lopes da Silva FH. Event-related EEG/MEG synchronization and desynchronization: basic principles. Clin Neurophysiol. Netherlands; 1999;110:1842–57. https://doi.org/10.1016/s1388-2457(99)00141-8
Pfurtscheller G, Brunner C, Schlögl A, Lopes da Silva FH. Mu rhythm (de)synchronization and EEG single-trial classification of different motor imagery tasks. Neuroimage. United States; 2006;31:153–9. https://doi.org/10.1016/j.neuroimage.2005.12.003
López-Larraz E, Escolano C, Montesano L, Minguez J. Reactivating the Dormant Motor Cortex After Spinal Cord Injury With EEG Neurofeedback: A Case Study With a Chronic, Complete C4 Patient. Clin EEG Neurosci. SAGE Publications Inc.; 2019;50:100–10. https://doi.org/10.1177/1550059418792153
Alawieh H, Liu D, Madera J, Kumar S, Racz FS, Fey AM, et al. Electrical spinal cord stimulation promotes focal sensorimotor activation that accelerates brain–computer interface skill learning. Proceedings of the National Academy of Sciences [Internet]. Proceedings of the National Academy of Sciences; 2025;122:e2418920122. https://doi.org/10.1073/pnas.2418920122
Hernandez-Rojas LG, Cantillo-Negrete J, Mendoza-Montoya O, Carino-Escobar RI, Leyva-Martinez I, Aguirre-Guemez A V., et al. Brain-Computer Interface Controlled Functional Electrical Stimulation: Evaluation With Healthy Subjects and Spinal Cord Injury Patients. IEEE Access. Institute of Electrical and Electronics Engineers Inc.; 2022;10:46834–52. https://doi.org/10.1109/ACCESS.2022.3170906
Vǔckovíc A, Wallace L, Allan DB. Hybrid brain-Computer interface and functional electrical stimulation for sensorimotor training in participants with tetraplegia: A Proof-of-Concept Study. Journal of Neurologic Physical Therapy. Lippincott Williams and Wilkins; 2015;39:3–14. https://doi.org/10.1097/NPT.0000000000000063
Gant K, Guerra S, Zimmerman L, Parks BA, Prins NW, Prasad A. EEG-controlled functional electrical stimulation for hand opening and closing in chronic complete cervical spinal cord injury. Biomed Phys Eng Express. Institute of Physics Publishing; 2018;4. https://doi.org/10.1088/2057-1976/aabb13
Baillet S. Magnetoencephalography for brain electrophysiology and imaging. Nat Neurosci [Internet]. 2017;20:327–39. https://doi.org/10.1038/nn.4504
Tadel F, Baillet S, Mosher JC, Pantazis D, Leahy RM. Brainstorm: A User-Friendly Application for MEG/EEG Analysis. Comput Intell Neurosci [Internet]. John Wiley & Sons, Ltd; 2011;2011:879716. https://doi.org/10.1155/2011/879716
Foldes ST, Boninger ML, Weber DJ, Collinger JL. Effects of MEG-based neurofeedback for hand rehabilitation after tetraplegia: Preliminary findings in cortical modulations and grip strength. J Neural Eng. Institute of Physics Publishing; 2020;17. https://doi.org/10.1088/1741-2552/ab7cfb
Foldes ST, Weber DJ, Collinger JL. MEG-based neurofeedback for hand rehabilitation. J Neuroeng Rehabil. BioMed Central Ltd.; 2015;12. https://doi.org/10.1186/s12984-015-0076-7
Schildt CJ, Thomas SH, Powell ES, Sawaki L, Sunderam S. Closed-loop afferent electrical stimulation for recovery of hand function in individuals with motor incomplete spinal injury: Early clinical results. 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). 2016. p. 1552–5. https://doi.org/10.1109/EMBC.2016.7591007
Zulauf-Czaja A, Al-Taleb MKH, Purcell M, Petric-Gray N, Cloughley J, Vuckovic A. On the way home: a BCI-FES hand therapy self-managed by sub-acute SCI participants and their caregivers: a usability study. J Neuroeng Rehabil. BioMed Central Ltd; 2021;18. https://doi.org/10.1186/s12984-021-00838-y
McGeady C, Vučković A, Singh Tharu N, Zheng YP, Alam M. Brain-Computer Interface Priming for Cervical Transcutaneous Spinal Cord Stimulation Therapy: An Exploratory Case Study. Frontiers in Rehabilitation Sciences. Frontiers Media SA; 2022;3. https://doi.org/10.3389/fresc.2022.896766
Petersen JA, Wilm BJ, Von Meyenburg J, Schubert M, Seifert B, Najafi Y, et al. Chronic cervical spinal cord injury: DTI correlates with clinical and electrophysiological measures. J Neurotrauma. 2012;29:1556–66. https://doi.org/10.1089/neu.2011.2027
Jurkiewicz MT, Mikulis DJ, McIlroy WE, Fehlings MG, Verrier MC. Sensorimotor cortical plasticity during recovery following spinal cord injury: A longitudinal fMRI study. Neurorehabil Neural Repair. 2007;21:527–38. https://doi.org/10.1177/1545968307301872
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra
This work is licensed under a Creative Commons Attribution 4.0 International License.
© Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra under a Creative Commons Attribution 4.0 International (CC BY 4.0) license which allows to reproduce and modify the content if appropiate recognition to the original source is given.
