Intra-cortical brain-machine interfaces for controlling upper-limb powered muscle and robotic systems in spinal cord injury.

ABSTRACT

OBJECTIVE: Intracortical brain-machine interface (iBMI) is an assistive strategy to restore lost sensorimotor function by bridging the disrupted neural pathways to reanimate paralyzed limbs. However, to date, none of the studies explored the trade-offs between the performance criteria of different iBMI systems that decode discrete upper limb movements from intracortical neural recordings. METHODS: A systematic review of electronic databases using different MeSH terms from January 1990 to December 2019 was conducted. IBM® SPSS statistics version 25 (Released 2017, Armonk, NY IBM) was used to evaluate for differences between groups using independent sample t-tests. RESULTS: A total of 18 patients from 15 studies were included in our analysis. The included studies involved iBMI controlled 5-robotic and 10-neuromuscular stimulated orthotics to perform skillful and coordinated movements that resulted in a clinically significant gain in tests of upper-limb functions. Pooled analysis revealed that the mean response time to execute 3-D reach and grasp task by the robotic-assisted limb was relatively longer (46.8 +/-101.5 s) compared to the neuro-muscular stimulated orthotics (15.8 +/-15.2 s); however, statistically insignificant [Mean difference (MD) 30.9, 95 % Confidence Interval (CI) -40.4-102.3, p = 0.35]. Furthermore, the accuracy in performing 3-D reach and grasp tasks after repetitive trials were better among patients with neuro-muscular stimulated orthotics (83.5 +/-12.7 %) compared to those with robotic-assisted prosthetic limb (69.1 +/- 23.6 %) with statistically significant difference (MD 15.9, 95 % CI 1.65-32.5, p = 0.05). CONCLUSION: Our study demonstrates that iBMI-assisted prosthetic limbs showed better accuracy and shorter response time among patients with neuro-muscular stimulated orthotics compared to robotic neuro-prosthetics.