Stefano Piazza1, Julio Gómez-Soriano2, Elisabeth Bravo-Esteban3, Diego Torricelli4, Gerardo Avila-Martin5, Iriana Galan-Arriero6, José Luis Pons7, Julian Taylor8. 1. Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain. Electronic address: to.stefano.piazza@gmail.com. 2. Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; Toledo Physiotherapy Research Group (GIFTO), Nursing and Physiotherapy School, Castilla La Mancha University, Toledo 45072, Spain. Electronic address: julio.soriano@uclm.es. 3. Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain; Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; iPhysio Research Group, San Jorge University Zaragoza, Spain. Electronic address: eli88_b26@hotmail.com. 4. Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain. Electronic address: diego.torricelli@csic.es. 5. Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain. Electronic address: gavila@sescam.jccm.es. 6. Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain. Electronic address: igalan@jccm.es. 7. Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain. Electronic address: jose.pons@csic.es. 8. Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; Stoke Mandeville Spinal Research, National Spinal Injuries Centre, Aylesbury HP218AL, UK; Harris Manchester College, University of Oxford, Oxford OX1 3TD, UK. Electronic address: jscott@sescam.org.
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 25-100ms 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 75ms ISI (p<0.001), compared to a small loss of excitability at 75ms ISI after iSCI (p<0.05). In addition, change in cutaneomuscular-conditioned H-reflex excitability at 50ms and 75ms 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.
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 25-100ms 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 75ms ISI (p<0.001), compared to a small loss of excitability at 75ms ISI after iSCI (p<0.05). In addition, change in cutaneomuscular-conditioned H-reflex excitability at 50ms and 75ms 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.
Authors: Stefano Piazza; Diego Torricelli; Julio Gómez-Soriano; Diego Serrano-Muñoz; Gerardo Ávila-Martín; Iriana Galán-Arriero; José Luis Pons; Julian Taylor Journal: Med Biol Eng Comput Date: 2018-01-17 Impact factor: 2.602