Non-invasive measurement of abnormal ventilatory mechanics in amyotrophic lateral sclerosis

In this study we investigated non-invasive, effort-independent measurement of ventilatory mechanics in patients with amyotrophic lateral sclerosis (ALS).Ventilatory mechanics were measured by optoelectronic plethysmography (OEP) in ALS patients and matched controls. Analysis determined whether OEP measurements correlated with standard clinical measures.ALS patients (N = 18) had lower forced vital capacity percent predicted (55.2 ± 22.0 L) compared with controls (N = 15; 104.7 ± 16.2 L) and higher ventilatory inefficiency (49.2 ± 9.0 vs. 40.0 ± 3.5, respectively; P < 0.001 for both measures). Lower tidal volumes within the diaphragm area correlated with the dyspnea subscore calculated from the ALS Functional Rating Scale-revised (P = 0.031), and paradoxical movement of the ribcage compared with the abdominal compartment was seen in the most severe cases.Evaluation of ventilatory mechanics in mild to severe ALS reveals dysfunction that is not readily detected by standard testing and ALS functional severity assessment measures. Muscle Nerve 54: 270-276, 2016.