Affiliation: | a Neuromuscular Research Laboratory, Schulthess Clinic, Lengghalde 2 - 8008 Zurich, Switzerland b M.E. Müller Foundation North America, Schulthess Clinic, Lengghalde 2 - 8008 Zurich, Switzerland c Lower Extremity Unit, Schulthess Clinic, Lengghalde 2 - 8008 Zurich, Switzerland |