Fig. 7
From: The role of spinal cord neuroanatomy in the variances of epidural spinal recordings
Quantification for recorded ESR components and intramuscular EMG recordings after lateral displacement of the stimulation lead. Motor thresholds for the medial lead position of all subjects (n=4) were verified within intramuscular EMG recordings and as follows: S1: 2.0 mA; S2: 6.0 mA; S3: 2.0 mA; S4: 2.9 mA. RMS was calculated for the ECAP (time window: 1-2.5 ms) and EMG (time window: 3-13 ms) components of the recorded ESRs and intramuscular EMG (IM, time window: 3-13 ms). A Data from respective subject S1 show signal strength change when stimulation moved from medial to lateral positions across multiple stimulation amplitudes for collected ESRs, shown as (1) ECAP (2.0 mA: 181 ± 2.72%; 3.0 mA: 60.8 ± 1.18%; 4.0 mA: 24.3 ± 0.33%; 5.0 mA: 21.6 ± 0.38%; 6.0 mA: 31.34 ± 0.45%) and (2) EMG components (2.0 mA: 326 ± 6.89%; 3.0 mA: 39.4 ± 2.37%; 4.0 mA: -29.2 ± 0.46%; 5.0 mA: -19.3 ± 0.69%; 6.0 mA: -32.8 ± 0.50%), and (3) intramuscular EMG (IM) recordings (2.0 mA: 1433 ± 54.0%; 3.0 mA: -70.5 ± 0.62%; 4.0 mA: -75.9 ± 0.31%; 5.0 mA: -73.1 ± 0.36%; 6.0 mA: -57.8 ± 0.74%). B Changes to signal strength were observed at motor thresholds for all subjects for recorded ESRs, including (1) ECAP (S1: 181 ± 2.72%; S2: -60.4 ± 0.20%; S3: -31.9 ± 0.10%; S4: 48.0 ± 1.20%) and (2) EMG components (S1: 327 ± 6.90%; S2: 193 ± 8.20%; S3: 17.4 ± 2.00%; S4: 45.1 ± 5.50%) and (3) intramuscular EMG (IM) recordings (S1: 1433 ± 54.0%; S2: 5171 ± 237%; S3: 1.20 ± 0.79%; S4: 365 ± 38.9%). Additional plots for subject comparisons containing RMS values are provided in Supplementary Fig. 9