Sleep disordered breathing and autonomic outcomes in adult patients with spinal muscular atrophy (SMA) receiving Risdiplam.

OBJECTIVES

Investigations on effects of risdiplam therapy in adult patients with Spinal Muscular Atrophy (SMA) have been limited to diurnal respiratory and motor function. We explored whether risdiplam can influence nocturnal respiratory events and autonomic function.

METHODS

Sixteen consecutive subjects ≥16 years old with SMA type 2 or 3 were studied before and 12 months after risdiplam therapy. They underwent nocturnal cardiorespiratory polygraphy for analysis of respiratory function and heart rate variability (HRV). In addition, their motor function was evaluated using the Revised Upper Limb Module (RULM) and the Hammersmith Functional Motor Scale Expanded (HFMSE) scales.

RESULTS

After therapy, apnoea/hypopnoea Index (AHI) and oxygen desaturation index decreased (p = 0.02), while time with oxygen saturation <90% and lowest oxygen saturation did not change. HRV analysis showed a decrease in the SD2/SD1 ratio (p = 0.03), suggesting a decrease in sympathovagal balance. RULM and HFMSE scores showed a borderline improvement. The SD2/SD1 change was correlated with the change in AHI but not with the change in respiratory function or motor scale scores.

CONCLUSIONS

In adult patients with SMA, risdiplam therapy may be associated with improvements in nocturnal respiratory function and autonomic activity. The reduction in respiratory events during sleep may contribute to improved autonomic balance.