Upper airway dysfunction in amyotrophic lateral sclerosis

Abstract

The ALS Functional Rating Scale (ALSFRS-R) is a validated rating instrument for monitoring the progression of disability in patients with ALS. The ALSFRS-R incorporates questions for the assessment of dyspnoea, orthopnea, and the need for ventilatory support. However, studies on the relationship of ALSFRS-R with objective measurements of respiratory function are scanty. Therefore, we set out to investigate the relationship of ALSFRS-R with respiratory function indices in ALS patients. We studied 49 consecutive, ambulatory, Caucasian patients with ALS. Five patients did not satisfactorily perform the lung function testing and they were excluded . All subjects were free from any major co morbidities. ALSFRS-R was assessed. Routine lung function tests, maximum static expiratory (Pemax) and inspiratory (Pimax) mouth pressures were measured. Respiratory muscle strength (RMS) was also calculated. ALSFRS-R (mean±SD) was 34.0±8.4. Patients had: age, y=62±10, FEV 1 , %pred=80±21, FVC, %pred=82±21, TLC, %pred=91±14, and DL CO , %pred=86±20. Pemax, %pred was 72±30, Pimax, %pred was 65±32, and RMS, %pred was 68±29. These pressures were below the normal limits in 25, 33, and 28 patients, respectively. ALSFRS-R was significantly correlated with Pemax, %pred, RMS%, pred, FEF 50 /FIF 50 , and FEV 1 /FIV 1 (r=0.45, p In conclusion, FEV 1 /FIV 1 index significantly correlates with ALSFRS-R. This correlation is substantial closer in the subgroup of ALS patients without bulbar involvement.