Age and method-specific differences in the efficacy of non-invasive brain stimulation in patients’ post-stroke limb spasticity: a meta-analysis

Abstract

Objective: The aim of this study was to evaluate the effectiveness of two non-invasive brain stimulation (NIBS) methods, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), on spasticity in post-stroke patients with respect to patient age and muscle type.

Methods: This meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. PUBMED (MEDLINE), Web of Science, Cochrane Library, and ExcerptaMedica Database (EMBASE) were searched for all randomized controlled trials (RCTs) published before December 2023.

Results: In patients with spasticity after stroke, both rTMS (SMD: -0.56, CI95%: -0.81, -0.31, P<0.0001) and tDCS (SMD: -0.74, CI95%: -0.89, -0.59, P=0.005) significantly reduced the modified Ashworth Scale (MAS) compared with the control group. rTMS and tDCS were more effective in patients < 60 years than those > 60 years. Both rTMS and tDCS were effective against upper limb spasticity, particularly in patients aged < 60 years. Chronicity of stroke did not affect the benefit of rTMS to reduce spasticity although tDCS was more effective at 2 months after stroke onset. The reduction in spasticity in patients with supratentorial lesions was demonstrated by tDCS. The effectiveness of rTMS in spasticity reduction was not affected by the stimulation rate, but the use of tDCS at < 2 mA significantly decreased spasticity. Anodal stimulation (tDCS) reduced spasticity after stroke, especially in patients < 60 years of age. Other therapies, such as robotic therapy, the use of virtual reality, and electroacupuncture, were less effective against spasticity than conventional physical therapy combined with tDCS. The effectiveness of rTMS in spasticity reduction was not affected by the level of development, although tDCS was more successful in developing countries.

Conclusions: Our findings suggest that NIBS should consider age, methods, and muscle type when treating patients with limb spasticity after stroke.