Abstract 88: Primed Therapy Accelerates Recovery of Upper Limb Function after Stroke

Abstract

Background: Upper limb impairment is common after stroke and recovery of upper limb function reaches a plateau within 6 months for most patients. We hypothesised that recovery can be accelerated by increasing the excitability and plasticity of the ipsilesional motor cortex, so that it is primed for upper limb therapy. This study tested the effects of priming upper limb therapy with Active Passive Bilateral Training (APBT). Methods: We enrolled 57 patients with first-ever monohemispheric ischaemic stroke in this randomised, controlled, single-centre, double-blinded trial. Priming consisted of 15 minutes of APBT, where patients actively flexed and extended their non-paretic wrist in a mechanical device, which moved their passive paretic wrist in mirror-symmetric flexion and extension. The control intervention consisted of 15 minutes of weak cutaneous electrical stimulation. Both groups completed the intervention prior to 20 minutes of upper limb therapy, 5 d/w for 4 w, starting 2 w after stroke. Upper limb function was assessed with the Action Research Arm Test at 2, 6, 12 and 26 w. Corticomotor excitability was assessed with transcranial magnetic stimulation. Corticospinal tract integrity and cortical activity during isometric grip with the paretic hand were assessed with MRI. The primary endpoint was recovery of upper limb function at 12 w, using Intention to treat (ITT) and per protocol (PP) analyses. Results: Primed patients were 3 times more likely than control patients to reach at least 75% of their maximum recovery within 12 w (ITT OR 2.7, 90% CI 1.1 - 7.0; PP OR 3.4, 90% CI 1.2 - 9.9). Corticomotor excitability was normalised to a greater extent following primed therapy than control (F3,129 = 2.91, p = 0.037). Conclusion: Priming upper limb therapy with APBT accelerated recovery of upper limb function and normalised motor cortex excitability. APBT is a simple, inexpensive way of enhancing the neural response to therapy and may increase the efficiency of upper limb rehabilitation after stroke.