STUDIO DEL SONNO IN PAZIENTI CON LESIONE MIDOLLARE ACUTA: VALUTAZIONE DEL CONTROLLO AUTONOMICO CARDIOVASCOLARE

Introduction. In patients with Spinal cord injuries (SCI), an altered autonomic cardiovascular control (ACC) has been described. Sleep is characterized by changes in ACC, namely a predominant sympathetic modulation during REM and an enhanced parasympathetic control during NREM sleep (N2 and N3). However, data on ACC during sleep in SCI patients are still lacking. Therefore, aim of the present study was to assess ACC during sleep in SCI patients. Methods. 21 SCI patients (cervical, C, n=8 and thoracic, T, n= 13) underwent a polysomnography within 1 year from the acute injury. ECG and respiratory traces were extracted and ACC was assessed using power spectral (PS) and symbolic analysis (SA). Consecutive segments of 250±50 beats were selected accordingly to the sleep stages (N2, N3, REM). Briefly, PS identifies the low frequency (LF) and the high frequency oscillation (HF). LF is marker of sympathetic modulation, while HF is marker of vagal modulation and synchronous with respiration. SA identifies three main indices, 0V%, index of sympathetic modulation, 2LV% and 2UV%, markers of vagal modulation. Statistical analyses were performed using a two-way ANOVA analysis. Results. PS results revealed a higher LF and a lower HF in T compared to C, regardless of sleep stage (42 vs 32 and 52 vs 64, p< 0.01); as to the differences through sleep stages, 0V% was significantly lower in N2 and N3 compared to REM in T (26 and 22 vs 39%, p=0.004) and in N3 compared to REM in C (18 vs 39%, p=0.003), while 2LV% decreased in REM compared to N2 and N3 in both groups. Conclusion. Our data showed that cervical SCI, but not thoracic SCI, are characterized by a decreased cardiac sympathetic modulation. Interestingly, the dynamic autonomic changes during N2, N3 and REM are maintained through sleep stages and similar in the two groups.