[1] Alexandria Fac Med, Alexandria, Egypt
[2] Univ Toronto, Div Neurosurg, Toronto, ON, Canada
[3] Univ South Dakota, Sanford Sch Med, Div Basic Biomed Sci, Vermillion, SD USA
[4] Thomas Jefferson Univ Hosp, Dept Neurol Surg, Philadelphia, PA USA
[5] Louisiana State Univ, Dept Commun Sci & Disorders, Baton Rouge, LA USA
[6] Univ S Florida, Dept Neurosurg & Brain Repair, Tampa, FL 33620 USA
[7] Ohio State Univ, Dept Neurol Surg, Columbus, OH USA