| Test | Group 1 | Group 2 | Group 3# |
| TST min | 276.4±109.6 | 342.8±111.4* | 333.0±106.7* |
| REM min | 40.0±27.6 | 79.5±18.0*** | 62.5±45.7* |
| Sleep efficiency % | 72.1±21.9 | 75.8±15.4 | 77.8±18.2 |
| RDI events·h−1 | |||
| Total | 15.9±16.7 | 0.2±0.6*** | 38.7±32.6** |
| REM | 18.2±18.0 | 0.3±1.3*** | 36.3±28.2* |
Data are presented as mean±sd. Neuromuscular disease patients (group 1) slept slightly shorter and had reduced rapid eye movement (REM) sleep time. The respiratory disturbance index (RDI) was lowest in normal subjects (group 2), elevated in group 1 and highest in obstructive sleep apnoea patients (group 3). Most respiratory events in group 1 were centrally related apnoeas and hypopnoeas. TST: total sleep time. *: p<0.5; **: p<0.01; ***: p<0.001.