[1] Zurcher RehaZentren, Klin Wald, Dept Pulm Med & Sleep Med, CH-8636 Wald, Switzerland
[2] Zurcher RehaZentren, Klin Wald, Dept Neurol & Neurorehabil, CH-8636 Wald, Switzerland
[3] Univ Witten Herdecke, Fac Hlth, Dept Pulm Med, D-58455 Witten, Germany
[4] Kingston Univ, Fac Hlth Social Care & Educ, London SW17 0RE, England
[5] St Georges Univ London, London SW17 0RE, England