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.