<qa>  What was the apnea hypopnea index?Until now, there is no validated German language screening questionnaire for symptoms of respiratory muscle weakness and SDB. Steier et al. published an English language questionnaire which was validated as a screening tool in 33 patients with very different neuromuscular disorders which were predominantly neurogenic Steier et al. 2011. In this study, SDB was defined by an apnea hypopnea index above 5 per hour. Nocturnal oxygen saturation and CO2 monitoring were not taken into account at all. In addition the questionnaire does not systematically cover sleep-related symptoms of SDB in detail such as sleep disruption and morning headache which have to be separated from daytime symptoms such as dyspnea or orthopnea, respectively. 