[1] Albert Einstein Coll Med, Dept Neurol, Bronx, NY 10461 USA
[2] Albert Einstein Coll Med, Dept Epidemiol, Bronx, NY 10461 USA
[3] Albert Einstein Coll Med, Dept Populat Hlth, Bronx, NY 10461 USA
[4] Albert Einstein Coll Med, Montefiore Headache Ctr, Bronx, NY 10461 USA
[5] Armstrong Atlantic State Univ, Dept Biol, Savannah, GA 31419 USA