Maintenance of cutaneomuscular neuronal excitability after leg-cycling predicts lower limb muscle strength after incomplete spinal cord injury. Issue 6 (June 2016)

• Record Type: Journal Article
• Authors: Piazza, Stefano; Gómez-Soriano, Julio; Bravo-Esteban, Elisabeth; Torricelli, Diego; Avila-Martin, Gerardo; Galan-Arriero, Iriana; Pons, José Luis; Taylor, Julian
• Is Part Of: Clinical neurophysiology. Volume 127:Issue 6(2016:Jun.)
• Page Start: 2402
• Page End: 2409
• Publication Date: 2016-06
• Subjects: Spinal cord injury -- Cutaneomuscular-conditioned H-reflex activity -- Leg-cycling -- Triceps Surae manual muscle score -- Ankle joint hypertonia -- SCI spasticity syndrome; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2016.03.007
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Rhythmic leg exercise changes spinal neuronal activity after spinal cord injury (SCI). Leg-cycling may improve cutaneous sensorimotor function after incomplete SCI. Cutaneous sensorimotor function after leg-cycling predicts leg strength after iSCI. Abstract: Objective: Controlled leg-cycling modulates H-reflex activity after spinal cord injury (SCI). Preserved cutaneomuscular reflex activity is also essential for recovery of residual motor function after SCI. Here the effect of a single leg-cycling session was assessed on cutaneomuscular-conditioned H-reflex excitability in relation to residual lower limb muscle function after incomplete SCI (iSCI). Methods: Modulation of Soleus H-reflex activity was evaluated following ipsilateral plantar electrical stimulation applied at 25–100 ms inter-stimulus intervals (ISI's), before and after leg-cycling in ten healthy individuals and nine subjects with iSCI. Results: Leg-cycling in healthy subjects increased cutaneomuscular-conditioned H-reflex excitability between 25 and 75 ms ISI ( p < 0.001), compared to a small loss of excitability at 75 ms ISI after iSCI ( p < 0.05). In addition, change in cutaneomuscular-conditioned H-reflex excitability at 50 ms and 75 ms ISI in subjects with iSCI after leg-cycling predicted lower ankle joint hypertonia and higher Triceps Surae muscle strength, respectively. Conclusion: Leg-cycling modulates cutaneomuscular-conditioned spinal neuronal excitability in healthy subjects and individuals with iSCI, and is related to residual lower limb muscle function. Significance: Cutaneomuscular-conditioned H reflex modulation could be used as a surrogate biomarker of both central neuroplasticity and lower limb muscle function, and could benchmark lower-limb rehabilitation programs in subjects with iSCI.