Polysomnographic studies in amyotrophic lateral sclerosis

We retrospectively reviewed 17 polysomnograms (PSG) in symptomatic amyotrophic lateral sclerosis (ALS) patients to assess the type and frequency of sleep disordered events and correlated these findings with pulmonary function tests (PFTs), presenting complaints, presence of bulbar dysfunction, and response to bi-level positive airway pressure (PAP) treatment. PSG revealed abnormalities in 16 patients. Complaints of orthopnea, daytime sleepiness (but not morning headaches) and a low negative inspiratory force (NIF) correlated with sleep disruption. However, neither the forced vital capacity (FVC) nor the NIF reliably predicted any specific PSG finding. Twelve of 13 patients treated with bi-level PAP responded favorably. Since the response to bi-level PAP is frequently gratifying, PSG should strongly be considered in ALS patients with suspected sleep disturbances.