In the subgroup of DFNB1-related deafness (N = 40), rs3918242 of MMP9 was significantly associated with LEAQ score at 18 months afterCI activation; also, according to a multiple regression model, the ratio of plasmalevels of pro-BDNF/BDNF measured at implantation was a significant predictor ofoverall LEAQ score at follow-up. The gene discussed is BDNF; the disease is deafness.