Role of training in SNIP maneuvers in Amyotrophic Lateral Sclerosis patients

Introduction: Sniff nasal inspiratory pressure (SNIP) is reliable for the diaphragm strength assessment in Amyotrophic lateral sclerosis (ALS) patients (pts). Recent studies in pts with neuromuscolar diseases demonstrated SNIP improvement after training. Aim: To determine if SNIP can improve after training in ALS pts, and to compare SNIP value before and after respiratory function tests (RFTs). Methods: We recruited 103 consecutive ALS pts at Bari Regional referring Centre, (62/41=M/F);80/103 had spinal onset. They performed 5-10 sniffs, and best value was recorded(S1). Spirometry, peak cough flow(PCF) and peak expiratory flow(PEF) were then performed. Moreover, further 5-10 sniffs were repeated, and the highest value recorded(S2). All RFTs were carried out as per international guidelines. T- student, chi-quadro tests, and linear regression were performed. Results: In group1 (78/103) S2 was ≥than S1. In Group2 (25/103) S2 was at least 20% Conclusions: Conversely to prior studies in other neuromuscular diseases, this study highlighted that SNIP values in ALS pts do not improve when training with repeated maneuvers was performed. Furthermore 25% of pts had a 20%drop instead. Thus, it might show a group more sensitive to diaphragm fatigue in need of closer follow-up.