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Effects of Lumbosacral Spinal Cord Epidural Stimulation for Standing after Chronic Complete Paralysis in Humans.

Rejc E, Angeli C, Harkema S - PLoS ONE (2015)

Bottom Line: During sitting, little or negligible EMG activity of lower limb muscles was induced by epidural stimulation, showing that the weight-bearing related sensory information was needed to generate sufficient EMG patterns to effectively support full weight-bearing standing.In general, electrode configurations with cathodes selected in the caudal region of the array at relatively higher frequencies (25-60 Hz) resulted in the more effective EMG patterns for standing.These results show that human spinal circuitry can generate motor patterns effective for standing in the absence of functional supraspinal connections; however the appropriate selection of stimulation parameters is critical.

View Article: PubMed Central - PubMed

Affiliation: Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America.

ABSTRACT
Sensory and motor complete spinal cord injury (SCI) has been considered functionally complete resulting in permanent paralysis with no recovery of voluntary movement, standing or walking. Previous findings demonstrated that lumbosacral spinal cord epidural stimulation can activate the spinal neural networks in one individual with motor complete, but sensory incomplete SCI, who achieved full body weight-bearing standing with independent knee extension, minimal self-assistance for balance and minimal external assistance for facilitating hip extension. In this study, we showed that two clinically sensory and motor complete participants were able to stand over-ground bearing full body-weight without any external assistance, using their hands to assist balance. The two clinically motor complete, but sensory incomplete participants also used minimal external assistance for hip extension. Standing with the least amount of assistance was achieved with individual-specific stimulation parameters, which promoted overall continuous EMG patterns in the lower limbs' muscles. Stimulation parameters optimized for one individual resulted in poor standing and additional need of external assistance for hip and knee extension in the other participants. During sitting, little or negligible EMG activity of lower limb muscles was induced by epidural stimulation, showing that the weight-bearing related sensory information was needed to generate sufficient EMG patterns to effectively support full weight-bearing standing. In general, electrode configurations with cathodes selected in the caudal region of the array at relatively higher frequencies (25-60 Hz) resulted in the more effective EMG patterns for standing. These results show that human spinal circuitry can generate motor patterns effective for standing in the absence of functional supraspinal connections; however the appropriate selection of stimulation parameters is critical.

No MeSH data available.


Related in: MedlinePlus

EMG and ground reaction forces recorded during full weight-bearing standing.Time course of EMG and ground reaction force recorded during representative standing without stimulation and with stimulation parameters that promoted standing with the least amount of assistance. Participants A45 and A53 were able to stand placing their hands on the horizontal bars of the standing apparatus to assist balance. Participants B07 and B13 also used elastic cords fixed to the apparatus to assist with hip extension (S1 Video). Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported for each participant. Participant A53 was stimulated with four programs (P.1 to P.4) delivered sequentially at 10 Hz, resulting in an ongoing 40 Hz stimulation frequency. IL: iliopsoas; GL: gluteus maximus; MH: medial hamstring; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.
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pone.0133998.g001: EMG and ground reaction forces recorded during full weight-bearing standing.Time course of EMG and ground reaction force recorded during representative standing without stimulation and with stimulation parameters that promoted standing with the least amount of assistance. Participants A45 and A53 were able to stand placing their hands on the horizontal bars of the standing apparatus to assist balance. Participants B07 and B13 also used elastic cords fixed to the apparatus to assist with hip extension (S1 Video). Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported for each participant. Participant A53 was stimulated with four programs (P.1 to P.4) delivered sequentially at 10 Hz, resulting in an ongoing 40 Hz stimulation frequency. IL: iliopsoas; GL: gluteus maximus; MH: medial hamstring; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.

Mentions: Four out of four research participants achieved full weight-bearing standing with minimal self-balance assistance when their specific stimulation parameters were used to stimulate the lumbosacral spinal cord (S1 Video, Fig 1). The two clinically sensory and motor complete participants (A45 and A53) were able to stand without any external assistance, placing their hands on the horizontal bars of the apparatus to assist balance. The other two participants (B07 and B13) also used elastic cords fixed to the standing frame to assist with hip extension. Representative EMG patterns recorded from the four participants during stable standing are shown in Fig 1. EMG activity was overall continuous (not rhythmic) and modulated over time in some muscles (i.e. VL in participant A45; GL and VL in participant B13; GL in participant B07). Standing could be achieved with a variety of EMG patterns. For example, MH and SOL were most consistently active in all participants, while the EMG activity of TA was little or negligible in B13 and B07. Also, IL was consistently active in A45 but not active in A53. Conversely, without stimulation, little or no EMG activity was recorded from the analysed muscles of all research participants. In this case, research participants achieved and maintained upright posture because of the trainers’ assistance at the knees and hips, and because of the weight-bearing action performed by the participants’ upper limbs. The greater amount of assistance during standing without stimulation resulted in the lower ground reaction forces (-46.9 ± 6.7%) as compared to standing with stimulation.


Effects of Lumbosacral Spinal Cord Epidural Stimulation for Standing after Chronic Complete Paralysis in Humans.

Rejc E, Angeli C, Harkema S - PLoS ONE (2015)

EMG and ground reaction forces recorded during full weight-bearing standing.Time course of EMG and ground reaction force recorded during representative standing without stimulation and with stimulation parameters that promoted standing with the least amount of assistance. Participants A45 and A53 were able to stand placing their hands on the horizontal bars of the standing apparatus to assist balance. Participants B07 and B13 also used elastic cords fixed to the apparatus to assist with hip extension (S1 Video). Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported for each participant. Participant A53 was stimulated with four programs (P.1 to P.4) delivered sequentially at 10 Hz, resulting in an ongoing 40 Hz stimulation frequency. IL: iliopsoas; GL: gluteus maximus; MH: medial hamstring; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4514797&req=5

pone.0133998.g001: EMG and ground reaction forces recorded during full weight-bearing standing.Time course of EMG and ground reaction force recorded during representative standing without stimulation and with stimulation parameters that promoted standing with the least amount of assistance. Participants A45 and A53 were able to stand placing their hands on the horizontal bars of the standing apparatus to assist balance. Participants B07 and B13 also used elastic cords fixed to the apparatus to assist with hip extension (S1 Video). Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported for each participant. Participant A53 was stimulated with four programs (P.1 to P.4) delivered sequentially at 10 Hz, resulting in an ongoing 40 Hz stimulation frequency. IL: iliopsoas; GL: gluteus maximus; MH: medial hamstring; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.
Mentions: Four out of four research participants achieved full weight-bearing standing with minimal self-balance assistance when their specific stimulation parameters were used to stimulate the lumbosacral spinal cord (S1 Video, Fig 1). The two clinically sensory and motor complete participants (A45 and A53) were able to stand without any external assistance, placing their hands on the horizontal bars of the apparatus to assist balance. The other two participants (B07 and B13) also used elastic cords fixed to the standing frame to assist with hip extension. Representative EMG patterns recorded from the four participants during stable standing are shown in Fig 1. EMG activity was overall continuous (not rhythmic) and modulated over time in some muscles (i.e. VL in participant A45; GL and VL in participant B13; GL in participant B07). Standing could be achieved with a variety of EMG patterns. For example, MH and SOL were most consistently active in all participants, while the EMG activity of TA was little or negligible in B13 and B07. Also, IL was consistently active in A45 but not active in A53. Conversely, without stimulation, little or no EMG activity was recorded from the analysed muscles of all research participants. In this case, research participants achieved and maintained upright posture because of the trainers’ assistance at the knees and hips, and because of the weight-bearing action performed by the participants’ upper limbs. The greater amount of assistance during standing without stimulation resulted in the lower ground reaction forces (-46.9 ± 6.7%) as compared to standing with stimulation.

Bottom Line: During sitting, little or negligible EMG activity of lower limb muscles was induced by epidural stimulation, showing that the weight-bearing related sensory information was needed to generate sufficient EMG patterns to effectively support full weight-bearing standing.In general, electrode configurations with cathodes selected in the caudal region of the array at relatively higher frequencies (25-60 Hz) resulted in the more effective EMG patterns for standing.These results show that human spinal circuitry can generate motor patterns effective for standing in the absence of functional supraspinal connections; however the appropriate selection of stimulation parameters is critical.

View Article: PubMed Central - PubMed

Affiliation: Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America.

ABSTRACT
Sensory and motor complete spinal cord injury (SCI) has been considered functionally complete resulting in permanent paralysis with no recovery of voluntary movement, standing or walking. Previous findings demonstrated that lumbosacral spinal cord epidural stimulation can activate the spinal neural networks in one individual with motor complete, but sensory incomplete SCI, who achieved full body weight-bearing standing with independent knee extension, minimal self-assistance for balance and minimal external assistance for facilitating hip extension. In this study, we showed that two clinically sensory and motor complete participants were able to stand over-ground bearing full body-weight without any external assistance, using their hands to assist balance. The two clinically motor complete, but sensory incomplete participants also used minimal external assistance for hip extension. Standing with the least amount of assistance was achieved with individual-specific stimulation parameters, which promoted overall continuous EMG patterns in the lower limbs' muscles. Stimulation parameters optimized for one individual resulted in poor standing and additional need of external assistance for hip and knee extension in the other participants. During sitting, little or negligible EMG activity of lower limb muscles was induced by epidural stimulation, showing that the weight-bearing related sensory information was needed to generate sufficient EMG patterns to effectively support full weight-bearing standing. In general, electrode configurations with cathodes selected in the caudal region of the array at relatively higher frequencies (25-60 Hz) resulted in the more effective EMG patterns for standing. These results show that human spinal circuitry can generate motor patterns effective for standing in the absence of functional supraspinal connections; however the appropriate selection of stimulation parameters is critical.

No MeSH data available.


Related in: MedlinePlus