The effects of anodal transcranial direct current stimulation and patterned electrical stimulation on spinal inhibitory interneurons and motor function in patients with spinal cord injury

Abstract

Supraspinal excitability and sensory input may play an important role for the modulation of spinal inhibitory interneurons and functional recovery among patients with incomplete spinal cord injury (SCI). Here, we investigated the effects of anodal transcranial direct current stimulation (tDCS) combined with patterned electrical stimulation (PES) on spinal inhibitory interneurons in patients with chronic incomplete SCI and in healthy individuals. Eleven patients with incomplete SCI and ten healthy adults participated in a single-masked, sham-controlled crossover study. PES involved stimulating the common peroneal nerve with a train of ten 100 Hz pulses every 2 s for 20 min. Anodal tDCS (1 mA) was simultaneously applied to the primary motor cortex that controls the tibialis anterior muscle. We measured reciprocal inhibition and presynaptic inhibition of a soleus H-reflex by stimulating the common peroneal nerve prior to tibial nerve stimulation, which elicits the H-reflex. The inhibition was assessed before, immediately after, 10 min after and 20 min after the stimulation. Compared with baseline, simultaneous application of anodal tDCS with PES significantly increased changes in disynaptic reciprocal inhibition and long-latency presynaptic inhibition in both healthy and SCI groups for at least 20 min after the stimulation (all, p < 0.001). In patients with incomplete SCI, anodal tDCS with PES significantly increased the number of ankle movements in 10 s at 20 min after the stimulation (p = 0.004). In conclusion, anodal tDCS combined with PES could induce spinal plasticity and improve ankle movement in patients with incomplete SCI.

Disrupted Ankle Control and Spasticity in Persons With Spinal Cord Injury: The Association Between Neurophysiologic Measures and Function. A Scoping Review

“…In the current review, 3/4 studies that included measures of SRC excitability and VAC ( Table 3) provide evidence of a direct association between these measures (15,36,43). All three studies that support a direct relationship between SRC excitability and VAC had interventional study designs (15,36,43). Among the VAC measures included in these studies were foot clearance, foot tapping, DF strength, PF strength, active range of motion, and walking distance over time.…”

“…This impaired ability to voluntarily activate ankle DF can negatively impact walking function (8). In the current review, 3/4 studies that included measures of SRC excitability and VAC ( Table 3) provide evidence of a direct association between these measures (15,36,43). All three studies that support a direct relationship between SRC excitability and VAC had interventional study designs (15,36,43).…”

“…For the two studies that measured active range of motion in the ankles, the first study demonstrated a possible association between this functional outcome with low frequency depression and presynaptic inhibition (15), while the other demonstrated a change in reciprocal and presynaptic inhibition, but not active range of motion (43). Lastly, in the study in which toe clearance during walking was measured, there was an association between change in toe clearance and reciprocal inhibition (15).…”

“…There were 10 studies that examined changes in SRCs. Four of 10 also included measures of VAC (15,36,38,43); all four included correlation and/or association analyses to quantify the relationship between SRCs and VAC. Nine of 10 studies with SRC measures also had measures of ankle spasticity (6,15,31,(36)(37)(38)(39)(40)(41); only six of these articles included correlation and/or association analyses to quantify the relationship between SRC excitability and spasticity (6,15,31,(36)(37)(38).…”

Polymerizing Pyrrole Coated Poly (l-lactic acid-co-ε-caprolactone) (PLCL) Conductive Nanofibrous Conduit Combined with Electric Stimulation for Long-Range Peripheral Nerve Regeneration

“…What’s more, electric stimulation (ES) can enhance the progress of nerve regeneration and accelerate axon outgrowth in many in vitro studies (Kerns et al, 1991; Gordon et al, 2008; Prabhakaran et al, 2011). Different ES paradigms have been investigated for nerve regeneration, such as pulsed electric fields, direct current and alternating current stimulation (Park et al, 2009; Su and Shih, 2015; Yamaguchi et al, 2016). However, few studies have focused on electrospinning conductive nerve guidance conduit (CNGC) and the combined use with ES for nerve regeneration in vivo .…”