The Board does not require that you maintain your certification however some employers, especially national ones do. If you do maintain NBCOT certification, you can use the abbreviation OTR or COTA. If you do not, you may only use OT or OTA. See OT Rules, §369.3, Use of Titles. Remember that you must hold a current license from this board, the Texas Board of Occupational Therapy Examiners, in order to practice or represent yourself as an OT, OTR, OTA, or COTA in Texas.