Reversing 21 years of chronic paralysis via non‐invasive spinal cord neuromodulation: a case study

Abstract

Objective:The objective of the current study was to investigate if a non-invasive spinal cord neuromodulation modality could restore sensorimotor functions in a patient with chronic spinal cord injury (SCI). Methods: In this study, transcutaneous electrical stimulation (tES) to the spinal cord was utilized to restore sensorimotor functions in a chronic SCI patient who sustained a traumatic C7 cervical cord injury 21 years ago. At baseline, the patient had very limited volitional movement in her right leg, and her left leg was completely paralyzed. tES parameters were optimized in eight stimulation sessions before the treatment. The therapeutic stimulation involved biphasic tES, applied to T11 and L1 spinal levels during a 1-hour standing and walking training, 2-4 times per week for 16 weeks. Results: Our pre-treatment tests indicated that a shorter burst duration (100 µsec) was more effective than a longer burst duration of tES in improving functional movements. After 32 training sessions with tES, the patient regained significant left-leg volitional movements (grade 0 to grade 10 according to the ISNCSCI scale). Right-leg motor scores also increased from 17 to 21. The tES treatment also improved her pinprick sensation (from 73 to 79). Upon completion of the treatment (52 sessions), the patient's standing ability noticeably improved. She could stabilize her knee to stand without any assistance. She could also squat while holding onto a walker. Interpretation: These promising results demonstrate beneficial effects of non-invasive tES in regaining volitional control of plegic lower limbs in patients with chronic paralysis.

Transcutaneous spinal cord stimulation and motor responses in individuals with spinal cord injury: A methodological review

“…The electrode configurations with regard to position and location varied substantially across experiments (Tables 6 and 7 ). The cathode was positioned dorsally over the vertebral column in the majority of studies, otherwise electrodes were used that alternated polarity within a biphasic pulse [ 16 – 18 , 23 , 40 , 69 , 70 ]. Some studies specified a paravertebral dorsal electrode orientation [ 16 – 19 , 68 ], whereas most others placed the electrode in the midline over the vertebral column [ 14 , 20 , 23 , 25 , 26 , 36 , 37 , 40 – 44 , 67 , 69 – 72 ].…”

“…The cathode was positioned dorsally over the vertebral column in the majority of studies, otherwise electrodes were used that alternated polarity within a biphasic pulse [ 16 – 18 , 23 , 40 , 69 , 70 ]. Some studies specified a paravertebral dorsal electrode orientation [ 16 – 19 , 68 ], whereas most others placed the electrode in the midline over the vertebral column [ 14 , 20 , 23 , 25 , 26 , 36 , 37 , 40 – 44 , 67 , 69 – 72 ]. Many studies targeted a single site, however, 8 out of 14 therapeutic investigations favoured the stimulation of multiple sites simultaneously [ 36 , 37 , 40 – 43 , 67 , 71 ].…”

“…Some studies specified a paravertebral dorsal electrode orientation [ 16 – 19 , 68 ], whereas most others placed the electrode in the midline over the vertebral column [ 14 , 20 , 23 , 25 , 26 , 36 , 37 , 40 – 44 , 67 , 69 – 72 ]. Many studies targeted a single site, however, 8 out of 14 therapeutic investigations favoured the stimulation of multiple sites simultaneously [ 36 , 37 , 40 – 43 , 67 , 71 ].…”

“…The use of this intra-pulse carrier frequency is poorly justified and appears to be for analgesic purposes, although no evaluation of this could be identified. Other therapeutic experiments selected simplified phase characteristics with either biphasic or monophasic rectangular-waves with a frequency ranging from 1–90 Hz, with 20–30 Hz the most commonly occurring selection [ 6 , 18 , 19 , 38 , 40 , 44 , 69 , 71 ]. The duration of therapeutic stimulation varied from bouts of <5 mins [ 37 , 40 , 67 ] to > 45 mins [ 36 , 38 , 68 ] and was generally paired with concomitant rehabilitative activities.…”

“…Other therapeutic experiments selected simplified phase characteristics with either biphasic or monophasic rectangular-waves with a frequency ranging from 1–90 Hz, with 20–30 Hz the most commonly occurring selection [ 6 , 18 , 19 , 38 , 40 , 44 , 69 , 71 ]. The duration of therapeutic stimulation varied from bouts of <5 mins [ 37 , 40 , 67 ] to > 45 mins [ 36 , 38 , 68 ] and was generally paired with concomitant rehabilitative activities. Recorded current ranges in therapeutic experiments reached a maximum of 180mA in the thoracolumbar region [ 67 ] and 210mA in the cervical region [ 43 ].…”