Voice Center Team

Randall Holdgraf, M.D | Email

210- 450-0700

Dr. Holdgraf is the 2019-2020 graduate of the Fellowship program in Laryngology and Voice Disorders and is currently a faculty member at the University of Texas Voice Center. He completed his undergraduate degree at Texas A&M University in College Station and earned his medical degree at the Texas A&M HSC School of Medicine. He completed his residency training in Otolaryngology-Head and Neck Surgery at The Texas A&M Health Science Center College of Medicine – Scott & White in Temple, Texas. His clinical interests include care of adult and pediatric patients with voice and swallowing disorders.[/vc_column_text]

John Nix | Email | Profile

University of Texas San Antonio

Associate Professor of Voice and Vocal Pedagogy | Singing Voice Specialist

210- 458-5678

John Nix, Tenor, is Associate Professor of Voice and Vocal Pedagogy at the University of Texas at San Antonio, coordinator of the Vocal Area for the 2011-2014 academic years, and founding director of the UTSA Vocal Arts Laboratory. Previously he was on the staff of the National Center for Voice and Speech in Denver, where he worked with Ingo Titze. Mr. Nix has also served on the music faculties of The University of Colorado at Denver and Eastern New Mexico University. He holds degrees in Arts Administration from Florida State University, in Vocal Performance from the University of Georgia and the University of Colorado at Boulder, and Certification in Vocology from the University of Iowa.  His current and former students include a member of the Mormon Tabernacle Choir, two Santa Fe Opera apprentices, members of the Army Soldiers’ Chorus, a second place winner in the National Federation of Music Clubs competition, a two-time finalist in the American Traditions Competition, and faculty members at universities in Montana, Texas, Wyoming and New York. Mr. Nix was the 2006 winner of the NATS/Voice Foundation Van Lawrence Award.

Marisa Leyden, SLP-CCC | Email

Voice Pathologist


Marisa Leyden received her undergraduate degree from The University of Iowa and graduate degree in Communication Sciences and Disorders from The University of South Florida.  Marisa joined the UT Health Voice Center after completing her clinical fellowship at Audie Murphy Memorial VA Hospital here in San Antonio.