. 2021 Nov 18;16(11):e0260166. doi: 10.1371/journal.pone.0260166

Table 6. Parameters selected by neurophysiological assessments investigating the effects of tSCS on spinal cord functioning in individuals with SCI.

Stimulation parameters selected by studies carrying out neurophysiological assessments into the properties of spinal cord stimulation with SCI participants.

		ELECTRODES			STIMULATION PROTOCOL			ELECTRICAL CHARACTERISTICS
Study	Patient position	Size/shape [Area]	Polarity	Location	Description	Frequency	Intensity	Phase Charge (μC)	Max Phase Charge Density (μC/cm²)
*Lower limb responses*
Dy et al., 2010 [14]	Lying prone, BWS standing, BWS stepping	ø 2.5 cm [4.9 cm²]	Cathode	T11-T12	Single, t₁ = 1ms, mono square wave pulses	1) Prone/ Standing: 0.5 Hz	24.7 - 83mA	25–83	16.9
Dy et al., 2010 [14]	Lying prone, BWS standing, BWS stepping	Pair 5.0 x 10.2 cm	Anodes	Iliac crests		2) Stepping: 0.25–0.33 Hz	Set to where consistent responses observed in all measured muscles in standing
Emeliannikov et al., 2016 [15]	Seated	-	-	T11-T12	t₁ = 1ms paired pulses (50ms inter-pulse interval)	0.3 Hz for H-Reflex	30–80 mA	30–80	-
Emeliannikov et al., 2016 [15]	Seated	-	-	-	t₁ = 1ms paired pulses (50ms inter-pulse interval)	0.3 Hz for H-Reflex	Lowest amplitude to completely supress the second stimulus of a pair
Hofstoetter et al., 2018 [16]	Lying supine	Pair ø 5 cm [2 x 19.6 cm²]	Alternating (anode first pulse, cathode second)	T11-T12 paravertebrally	Charge balanced, symmetric biph rectangular t₁ = 1ms	-	32–86 mA Adjusted to reach target threshold >100uV in all muscle groups studied	32–86	2.2
Hofstoetter et al., 2018 [16]		8 x 13 cm	Alternating	Para-umbilically lower abdomen	Charge balanced, symmetric biph rectangular t₁ = 1ms	-		32–86	2.2
Hofstoetter et al., 2019 [17]	Lying supine	5 x 9 cm [45 cm²]	Alternating (anode first pulse, cathode second)	T11—T12 paravertebrally	Charge balanced, symmetric biph rectangular t₁ = 1ms	-	Adjusted to elicit control-PRM reflexes in the right soleus with amplitudes that best matched the control-H reflexes and to elicit PRM reflexes in other muscles studied	-	-
		Pair 8 x 13 cm	Alternating	Lower abdomen
Murray and Knikou, 2019 [20]	Lying supine	10.2 x 5.1 cm [52 cm²]	Cathode	T10—L1/L2	1) Intervention: alternating suprathreshold and subthreshold stimulation (60 mins/session), mono square wave t₁ = 1ms	1) 0.2Hz	Selected based on threshold to produce right soleus evoked potential (96.9 ± 24 mA). Treatment sessions ranged from 0.4–4.3 times this resting threshold	97	1.9
Murray and Knikou, 2019 [20]		Connected pair 10.2 x 5.1 cm²	Anode	Para-umbilically/ iliac crests	2) Assessment: mono square wave t₁ = 1ms	2) 0.1, 0.125, 0.2, 0.33, 1.0 Hz	From below motor threshold until plateau reached	417	8.0
Atkinson et al., 2020 [26]	Lying supine	ø 1.8 cm [2.6 cm²]	Cathode	Midline T9-T10 (n = 1), T10-T11(n = 7), T11-T12 (n = 6), T12-L1 (n = 1)	Single, mono square wave pulses, t₁ = 1ms	-	0-100mA or until response magnitude plateaued	0 to 100	39.3
Atkinson et al., 2020 [26]		Pair 5 x 9 cm	Anode	Anterior superior iliac spines
Militskova et al., 2020 [25]	Lying supine, BWS standing	ø 2.5 cm [4.9 cm²]	Stimulating	Midline T9-T10, T10-T11, T11-T12, T12-L1, and L1-L2	Mono rectangular pulses t₁ = 1ms	-	30-100mA or maximum tolerated	30 to 100	20.4
Militskova et al., 2020 [25]	Lying supine, BWS standing	Pair 4 x 2 cm	Reference	Lower abdomen
Islam et al., 2021 [72]	Lying supine, BWS stepping	10.2 × 5.1 cm [52 cm²]	Cathode	Longitudinally between T10-L1 vertebrae	1) Single mono pulses t1 = 1ms		248 ± 87.06 mA for single pulses,	248 ± 87.06	4.8
Islam et al., 2021 [72]	Lying supine, BWS stepping	pair 10.2 × 5.1 cm	Anode	Iliac crests or either side of abdominal muscles	2) Pulse train of 12 1 ms pulses with a total duration of 33 ms randomly across the step cycle	333.3 Hz	57 to 160 mA for pulse trains Intensity set for Sol TEPs to be equivalent to the Sol H-reflex	57 to 160	18.8 to 53
*Upper limb responses*
Wu et al., 2020 [23]	Seated	5 x 10cm [50 cm²]	1) Alternating polarity	4cm caudal to C7 (T2-T4)	1) Anode posterior 2ms, t₁ = 1ms biph,	0.2Hz	80–175% of RMT, (RMT = 5.5–51 ma)	89 μc mono	1.8
			2) Cathode posterior for majority		2) Cathode posterior 2ms, t₁ = 1ms biph,			89 μc biph	1.8
			2) Cathode posterior for majority		3) Cathode posterior t₁ = 0.5ms biph,			89 μc biph	1.8
		5 x 10cm	1) Alternating polarity	1-2cm above sternal notch (C4-C5 levels anteriorly)			Threshold calculated as enough to elicit > 50uv in 5/10 reps
			2) Anode anterior for majority
			2) Anode anterior for majority		4) Cathode posterior t₁ = 1ms mono

Abbreviations: biph; biphasic, mono; monophasic, PRM; posterior root-muscle, RMT; resting motor threshold, Sol; soleus, TEP; transpinal evoked potential. Where more than one test protocol existed within a given publication, the protocols were detailed using numerical listing: 1) 2) 3) etc. Phase charge density is given in terms of upper limits.