1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
2. Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
3. Department of Medicine, Division of Pulmonary and Critical Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA, and
4. Thayer School of Engineering, Dartmouth College, Hanover, NH, USA