[1] Duke Univ, Dept Med Neurol, Med Ctr, Durham, NC 27710 USA
[2] Metrohlth Med Ctr, Dept Nursing, Cleveland, OH USA
[3] St Lukes Episcopal Hosp, Houston, TX 77030 USA
[4] Univ Penn, Dept Neurosurg, Philadelphia, PA 19104 USA
[5] Baylor Coll Med, Dept Neurol, Houston, TX 77030 USA
[6] Yale New Haven Hosp, Haven, CT USA