Table 2.
NIRS data availability and quality during standardized supine-stand tests. In total, there were 58 laboratory recordings (2 sensors measuring 17 participants once and 4 participants three times (after amendment)) and 240 at-home recordings (2 sensors measuring three times during 40 measurement days of 21 participants). Data are presented as number of recordings (percentage) when not indicated otherwise
| Condition | Laboratory (n = 58) | At home (n = 240) | ||
|---|---|---|---|---|
| Channel | Long | Short | Long | Short |
| Absent | 0 (0) | 0 (0) | 16 (7) | 16 (7) |
| Accidental discontinuation | - | - | 8 (3) | 8 (3) |
| Performed after removing sensor | - | - | 2 (1) | 2 (1) |
| Lost connection between sensor and application | - | - | 2 (1) | 2 (1) |
| Unknown (not performed) | - | - | 4 (2) | 4 (2) |
| Recordings discarded | 0 (0) | 6 (10) | 32 (13) | 65 (27) |
| SQI (mean (SD)) | 4.6 (0.4) | 4.6 (0.7) | 4.0 (1.0) | 3.9 (1.1) |
| SQI < 3 | 0 (0) | 4 (7) | 25 (10) | 50 (21) |
| Large baseline shift (> 10 µM) | 0 (0) | 2 (3) | 6 (3) | 14 (6) |
| Irregular amplitude | 0 (0) | 0 (0) | 0 (0) | 1 (0) |
| Sensitivity analyses (supplementary material) | ||||
| SQI < 2 | 0 (0) | 1 (2) | 14 (6) | 22 (9) |
| Large baseline shift (> 10 µM) | 0 (0) | 2 (3) | 8 (3) | 18 (8) |
| Irregular amplitude | 0 (0) | 0 (0) | 0 (0) | 1 (0) |
| SQI < 3.5 | 3 (5) | 5 (9) | 48 (20) | 64 (27) |
| Large baseline shift (> 10 µM) | 0 (0) | 2 (3) | 3 (1) | 10 (4) |
| Irregular amplitude | 0 (0) | 0 (0) | 0 (0) | 1 (0) |
SQI signal quality index. Signal exclusion was only identified as due to irregular amplitude or large baseline shift when signal was not already excluded because of low SQI