Cortical and autonomic arousals from sleep in patients with Duchenne muscular dystrophy or Amyotrophic lateral sclerosis under noninvasive ventilation

Arousals occur during sleep spontaneously or following respiratory disorders, and are recognised as cortical and autonomic activation. Autonomic nervous system (ANS) activity may differ between Duchenne muscular dystrophy (DMD) and Amyotrophic lateral sclerosis (ALS). We analysed nocturnal cardiorespiratory (Somnocheck Micro, Weinmann) and polysomnography (PSG) recordings (SomnoLab2, Weinmann), simultaneously performed in ventilated patients, 16 affected by DMD and 16 by ALS. Our aims were to evaluate relationships between: (1) autonomic arousals (AA), detected as pulse wave amplitude variations, and cortical arousals (CA); (2) respiratory AA and disordered breathing events; (3) occurrence of AA and ANS activity, assessed with the analysis of heart rate (HR) variability. Respiratory events and AA were automatically detected by the cardiorespiratory monitor. CA were visually detected on the PSG. HR variability was analysed on the PSG ECG signal by a commercial software (Kubios HRV). In the DMD group, AA exceeded CA rate (40.4 +/- 10 vs. 19.7 +/- 5 P < 0.001), but they were significantly correlated (r = 0.68, P = 0.002); conversely, in ALS the average rates of AA and CA were similar (14.1 +/- 12 vs. 14.9 +/- 5, P = 0.78) but they were not correlated (r = 0.23, P = 0.39). The rate of respiratory AA did not differ from the rate of respiratory events in DMD (8.4 +/- 6.5 vs. 9.2 +/- 6.7/h, P = 0.10), but it was lower in ALS (2.4 +/- 2.8 vs. 6.2 +/- 5.3/h, P = 0.003). In DMD, the rate of AA was positively correlated to low (rho = 0.69, P = 0.002) while in ALS it was correlated to high frequencies (rho = 0.50, P = 0.047) of HR. We concluded that in neuromuscular diseases AA variably occur in relationship to ANS activity.