Table 3.
Latencies and Amplitudes of SEP Components—Pre–Posttest—Studies made on healthy volunteers.
| Study/sample size | SEP components (latencies and amplitudes) | Test time/follow-up and statistical analysis | Significant effects |
|---|---|---|---|
| Ashton et al. (6) 32 healthy volunteers |
MN at the wrist, troughs and peaks utilizing latency criterion of: P1:60-100 msec, N1:100-160 msec, P2: 160-260 msec, N2 and P3: 260-360 msec |
Pretreatment/- 15 min Post-I/0 min Post-II/+15 min Post-III/30 min Post-IV / +45 min 1-way ANOVA and 2-way ANOVA |
Consideration of means showed a decrease of N1P2 amplitude and increase of N1 latency in the TENS group as compared to placebo or aspirin group. For the SEP total excursion measure, a significant effect occurred in the time epoch 30 min post-treatment (F = 3.92, df = 2, 29, P < 0.05) and a marginal effect in the last time epoch 45 min post-treatment (F = 2.79, df = 2, 29, 0.10 > P > 0.05). |
| Cogiamanian et al. (38) 12 healthy volunteers |
The SEP of MN at the wrist: P14, N20 latency and amplitudes and TN SEPs at the ankle: N9, N22, P30, P39, latency and amplitudes | Baseline Post-I/0 min Post-II/+20 min 1-way ANOVA and 2-way ANOVA Post hoc analysis |
Compering changes in TN and MN SEPs after anodal tsDCS over the thoracic spinal cord con- firmed that P30 component elicited by TN stimulation decreased by 49% in amplitude (baseline 0.78 ± 0.12 lV, T0 0.40 ± 0.07 lV; t- test: p = 0.01), but remained statistically unchanged in latency (baseline 28.8 ± 0.67 ms, T0 28.5 ± 0.57 ms; t-test: p = NS). After thoracic tsDCS all the median nerve SEP components remained unchanged (P14 amplitude: baseline 0.68 ± 0.10 lV, T0 0.70 ± 0.04 lV; t-test: p = NS; P14 latency: baseline 13.9 ± 0.48 ms, T0 13.7 ± 0.48 ms; t-test: p = NS). |
| Kang et al. (39) 20 healthy volunteers |
The SEP of MN at the wrist: N13, N20, P25, N30 latency and amplitudes | Baseline During the stimulation period Post-I / + 20 min 1-way ANOVA and Scheffe's post hoc correction |
EA demonstrated a higher mean amplitude in N20 during the stimulation and post- stimulation periods compared with baseline. In N30 the difference only appeared during the stimulation period when treated with EA. These effects were not observed when subjects were treated with sham TENS or 2 Hz TENS. No significant differences were observed in other components of MN-SEPs, either for mean latency or amplitude. |
| Schabrun et al. (33) 13 healthy volunteers |
The SEP of MN at the wrist: peak-to-peak amplitudes: P14-N20, N20-P25, P25-N33, N13, N9 and latencies N9, N14 and N20 | Before and after completion of the stimulation period 1-way ANOVA Linear regression analyses Where appropriate, post-hoc tests were performed |
Neither motor or sensory PES induced a change in the latency of the N13/N20 1. Motor movement: Motor PES increased the amplitude N20-P25 (post-hoc pre vs. post p = 0.007,) no change in the P14-N20 (post-hoc pre vs. post p = 0.34) or P25-N33 (post-hoc pre vs. post p = 0.77) components. 2. Sensory 100 Hz: Sensory PES increased the amplitude of P14-N20 (post-hoc pre vs. post p = 0.01,) and reduced P25-N33 (post-hoc pre vs. post p = 0.001) The N20-P25 component was unchanged by sensory PES (post-hoc pre vs. post p = 0.34). |
| Rocchi et al. (40) 15 healthy volunteers |
Digital nerves of the right index finger were stimulated The UL SEPs: amplitudes: P14, N20-P25 and N20 peak latency |
Before and 5 min after the completion of the 45 min stimulation period 2-way ANOVA and dependent Student's t-test |
HF-RSS increased the amplitude of N20-P25 (p < 0.001) and P14 (p < 0.001) immediately after HF-RSS was applied. No changes in N20 or P14 latency were observed (p values of all t- tests > 0.05) |
| Zarei et al. (41) 40 healthy volunteers |
The SEP of MN at the hand: N100, P200, and N400 latency and amplitudes |
Baseline Post-I / 0 min Post-II/+30 min Post-III/60 min 2-way ANOVA Where appropriate, post-hoc tests were performed |
The magnitude of N100, P200 waves, and theta and alpha band power was significantly suppressed following the TENS intervention. The suppression of the magnitude of the N100 wave lasted at least an hour. However, the effects of TENS on the magnitude of P200 only remained for 30 min after the intervention. |
MN, Median nerve; TENS, Transcutaneous Electrical Nerve Stimulation; EA, Electroacupuncture; UL, Upper limb; HF-RSS, High Frequency Repetitive Somatosensory Stimulation; LL, Lower limb; TN, Tibial nerve; tsDCS, Transcutaneous Spinal (anodal and cathodal) Direct Current Stimulatio.