Inspiratory airflow dynamics during sleep in veterans with Gulf War illness: a controlled study

To determine whether veterans with Gulf War Illness (GWI) are distinguished by sleep-disordered breathing, we compared inspiratory airflow dynamics during sleep between veterans with GWI and asymptomatic veterans of the first Gulf War. We recruited 18 male veterans with GWI and 11 asymptomatic male veterans of the first Gulf War by advertisement. The two samples were matched for age and body mass index. Each participant underwent a first full-night polysomnogram (PSG) while sleeping supine using standard clinical monitoring of sleep and breathing. A second PSG was performed measuring airflow with a pneumotachograph in series with a nasal mask and respiratory effort with a supraglottic pressure (Psg) catheter to assess the presence of inspiratory airflow limitation during supine N2 sleep. We determined the prevalence of flow-limited breaths by sampling continuous N2 sleep and plotting inspiratory flow against Psg for each breath in the sample. We expressed the prevalence of flow-limited breaths as their percentage in the sample. Compared to controls, veterans with GWI had an increased frequency of arousals related to apneas, hypopneas, and mild inspiratory airflow limitation. During supine N2 sleep, veterans with GWI had 96 +/- 5% (mean +/- SD) of their breaths flow-limited while controls had 36 +/- 25% of their breaths flow limited (p < 0.0001). Veterans with GWI experience sleep-disordered breathing that may distinguish them from asymptomatic veterans of the first Gulf War.