Eusho Byxthar was a female Betazoid physician born in 2281. She was doctor to the Troi family for many years, having treated the grandparents of Lwaxana Troi. She delivered Lwaxana's son, Barin, in 2372. (TNG - Slings and Arrows eBook: The Insolence of Office)

Perhaps coincidentally, Eusho Byxthar shares a surname with Betazoid Meron Byxthar from TNG novel: Losing the Peace.