Deafness after Skull Encephalic Trauma and Cochlear Implant

Abstract

Objective: Total deafness may be among the consequences of a skull encephalic trauma with bilateral fracture of the temporal bone. The recovery of hearing function can occur with the application of a cochlear implant. The functional results will depend on the presence of neurological or neuropsychological alterations both morphological at cochlear level. Method: We present four cases of postverbal total deafness subsequent to single and/or bilateral fracture of the temporal bone who underwent cochlear implantation from 2000 to 2009. Two patients had monolateral anacusia with onset in childhood contralateral to the fracture, and 2 patients had injuries with bilateral fracture of the petrosal bone. Results: In all cases correct positioning of the electrode array was possible without complications after surgery, and at the activation all electrodes were working. Because of the greater encephalic damage and the reduced capacity of cortical integration, in 2 patients the spectral type of stimulation strategies was chosen with low rates of stimulation. One year after the activation of the perceptual-verbal ability all patients reached the recognition level in open set, and 3 patients were able to have telephone conversations with familiar voices. The patients with greater neurological complications also obtained significant benefits on the cognitive side. Conclusion: In these cases different variables affect the recovery of hearing function with the cochlear implant. CNS damage may be associated with fibrosis or ossification of the cochlea and limits to the proper insertion of the electrodes array. The neuropsychological and neurological complications, in our opinion, are not factors of exclusion.