Table 2.
Visuomotor measures for the three groups
| Visuomotor measures | Patients with schizophrenia, Mean ± SD | Healthy control subjects Mean ± SD | Non-psychotic siblings Mean ± SD | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Single task | Dual-DIST | Dual-ADD | Single task | Dual DIST | Dual ADD | Single task | Dual-IST | Dual-ADD | |
| Force control | |||||||||
| Tracking error, RMSe | 0.12 ± 0.05 | 0.15 ± 0.07 | 0.17 ± 0.09 | 0.09 ± 0.03 | 0.10 ± 0.04 | 0.12 ± 0.04 | 0.09 ± 0.03 | 0.11 ± 0.03 | 0.13 ± 0.04 |
| Release duration, ms | 166 ± 46 | 171 ± 61 | 179 ± 89 | 148 ± 30 | 142 ± 45 | 145 ± 44 | 140 ± 33 | 135 ± 53 | 136 ± 54 |
| Force-onset, ms | 118 ± 22 | 119 ± 38 | 150 ± 120 | 115 ± 29 | 120 ± 46 | 132 ± 50 | 113 ± 35 | 105 ± 22 | 113 ± 22 |
| Force-offset, ms | 165 ± 50 | 166 ± 62 | 171 ± 59 | 161 ± 43 | 155 ± 47 | 160 ± 46 | 151 ± 33 | 136 ± 41 | 157 ± 39 |
| Eye tracking | |||||||||
| Saccade detection, % | 58 ± 24 | 34 ± 24 | 70 ± 23 | 36 ± 16 | 14 ± 9 | 74 ± 19 | 38 ± 21 | 17 ± 14 | 69 ± 20 |
| Saccade latency, ms | X | 217 ± 53 | 321 ± 65 | X | 182 ± 30 | 378 ± 72 | X | 180 ± 27 | 354 ± 68 |
| Saccade duration, ms | X | 161 ± 89 | 232 ± 71 | X | 157 ± 77 | 189 ± 50 | X | 117 ± 75 | 192 ± 57 |
| SPEM gain, ratio | 0.60 ± 0.34 | X | X | 0.86 ± 0.25 | X | X | 0.89 ± 0.22 | X | X |
| TMS | |||||||||
| MEPs, NU | 1.83 ± 0.54 | 1.70 ± 0.51 | 1.74 ± 0.55 | 1.43 ± 0.37 | 1.53 ± 0.46 | 1.60 ± 0.51 | 1.51 ± 0.54 | 1.56 ± 0.56 | 1.53 ± 0.51 |
| SICI, % | 30 ± 15 | 28 ± 13 | 29 ± 14 | 38 ± 14 | 44 ± 13 | 43 ± 14 | 39 ± 15 | 42 ± 20 | 43 ± 18 |
| CSP, ms | 745 ± 164 | 773 ± 122 | 810 ± 166 | 906 ± 177 | 887 ± 167 | 917 ± 174 | 848 ± 201 | 812 ± 188 | 793 ± 204 |
Main measures (mean ± SD) of performance in force control, eye tracking and TMS are detailed for all groups in (i) the Single-task tracking condition and the two Dual-task conditions with (ii) dual-task distraction trials (Dual-DIST) and (iii) dual-task addition trials (Dual-ADD).
Note that saccade occurrence in Dual-ADD did not reach 100% since subjects tended to avoid saccades to targets with small eccentricity (relative to the cursor). Saccade detection in the single-task condition is the occurrence of spontaneous non-required but task-related saccades during grip force-tracking (patients with schizophrenia versus healthy control subjects: P < 0.001; patients with schizophrenia versus non-psychotic siblings: P = 0.01).
CSP = cortical silent period; HC = healthy control group; NU = normalized unit (normalized on Rest values); PSZ = patients with schizophrenia; RMSe = root mean square error; SIB = non-psychotic siblings; X = absence of data in this condition.