- Nerve growth factor serum level is reduced in patients with sensorineural hearing impairment: possible clinical implications. Salvinelli, F., Casale, M., Greco, F., Trivelli, M., Di Peco, V., Amendola, T., Antonelli, A., Stampachiacchiere, B., Aloe, L. J. Biol. Regul. Homeost. Agents (2002)