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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: 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.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.

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 during sitting to standing transition.Time course of EMG and ground reaction force recorded during sitting to standing transition from participants A45 (Panel A) and A53 (Panel B). Panels C and D: Spinal cord evoked responses taken from the windows entered in A and B, respectively (left window: sitting; right window: standing). The black trace is the average of 15 spinal cord evoked potentials represented in grey. Vertical grey dotted line: stimulation onset. Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported. 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; RF: rectus femoris; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.
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pone.0133998.g002: EMG and ground reaction forces during sitting to standing transition.Time course of EMG and ground reaction force recorded during sitting to standing transition from participants A45 (Panel A) and A53 (Panel B). Panels C and D: Spinal cord evoked responses taken from the windows entered in A and B, respectively (left window: sitting; right window: standing). The black trace is the average of 15 spinal cord evoked potentials represented in grey. Vertical grey dotted line: stimulation onset. Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported. 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; RF: rectus femoris; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.

Mentions: The sensory information related to the transition from sitting to standing (S2 Video) remarkably modulated the EMG activity of lower limb muscles. Representative examples of EMG and force data recorded from A45 and A53 showed little or no EMG during sitting (Fig 2A and 2B, respectively); the transition of weight onto the lower limbs promoted a significant increase in the level of EMG activity. Spinal cord evoked responses were not detected in some muscle during sitting (see MH in Fig 2C and SOL in Fig 2D as examples), while they were recorded in all muscles during standing. The amplitude of spinal cord evoked responses was greater in standing than in sitting for all participants and investigated muscles, with some exception showed by TA and IL (S1 Fig). Such EMG modulation occurred during the sitting to standing transition without any change in the stimulation parameters, which were the same delivered to the research participants’ spinal cord in order to achieve full weight-bearing standing with minimal assistance (Fig 1). These stimulation parameters were substantially different among individuals: frequency and amplitude ranged from 25 to 60 Hz and from 1.0 to 9.0 V, respectively. Electrode configurations generally included the placement of cathodes in the caudal portion of the array and an individual-specific assignment of other electrodes (both anodes and cathodes), resulting in configurations dissimilar among research participants.


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 during sitting to standing transition.Time course of EMG and ground reaction force recorded during sitting to standing transition from participants A45 (Panel A) and A53 (Panel B). Panels C and D: Spinal cord evoked responses taken from the windows entered in A and B, respectively (left window: sitting; right window: standing). The black trace is the average of 15 spinal cord evoked potentials represented in grey. Vertical grey dotted line: stimulation onset. Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported. 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; RF: rectus femoris; 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.g002: EMG and ground reaction forces during sitting to standing transition.Time course of EMG and ground reaction force recorded during sitting to standing transition from participants A45 (Panel A) and A53 (Panel B). Panels C and D: Spinal cord evoked responses taken from the windows entered in A and B, respectively (left window: sitting; right window: standing). The black trace is the average of 15 spinal cord evoked potentials represented in grey. Vertical grey dotted line: stimulation onset. Stimulation frequency, amplitude and electrode configuration (cathodes in black, anodes in grey, and non-active in white) are reported. 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; RF: rectus femoris; VL: vastus lateralis; TA: tibialis anterior; MG: medial gastrocnemius; SOL: soleus.
Mentions: The sensory information related to the transition from sitting to standing (S2 Video) remarkably modulated the EMG activity of lower limb muscles. Representative examples of EMG and force data recorded from A45 and A53 showed little or no EMG during sitting (Fig 2A and 2B, respectively); the transition of weight onto the lower limbs promoted a significant increase in the level of EMG activity. Spinal cord evoked responses were not detected in some muscle during sitting (see MH in Fig 2C and SOL in Fig 2D as examples), while they were recorded in all muscles during standing. The amplitude of spinal cord evoked responses was greater in standing than in sitting for all participants and investigated muscles, with some exception showed by TA and IL (S1 Fig). Such EMG modulation occurred during the sitting to standing transition without any change in the stimulation parameters, which were the same delivered to the research participants’ spinal cord in order to achieve full weight-bearing standing with minimal assistance (Fig 1). These stimulation parameters were substantially different among individuals: frequency and amplitude ranged from 25 to 60 Hz and from 1.0 to 9.0 V, respectively. Electrode configurations generally included the placement of cathodes in the caudal portion of the array and an individual-specific assignment of other electrodes (both anodes and cathodes), resulting in configurations dissimilar among research participants.

Bottom Line: 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.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.

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