[Effect of cochlear implantation on bilateral perceived tinnitus of postlingually deafened patients]

The aim of the study was to evaluate the effects of cochlear implantation on bilateral perceived tinnitus of postlingually deafened patients.

Total of 32 postlingually deafened cochlear implant recipients (13 males, 19 females; 31 unilateral,1 bilateral cochlear implantation) with bilateral tinnitus were assessed by Tinnitus Handicap Inventory (THI) before and after implantation. Furthermore, characteristics information of tinnitus were recorded to analyze the variety of tinnitus. Intensity of tinnitus in ispilateral and contralateral ears was investigated when cochlear implant was switched on and off. Statistical analysis was performed by SPSS 18.0.

Twenty-two patients (71.0%) got a decreased THI score of more than 20 points after the operation. The average THI score of pre-operation was 56.4±18.1, and post-operation score was 24.7±22.7. A paired-samples t test analysis showed a significant difference of the THI total scores (t=8.037, P<0.05). Tinnitus in the ipsilateral ear improved in 81.9% (27/33) patients and 18.2% (6/33) unchanged. Tinnitus in the contralateral ear improved in 71.0% (22/31) patients, 16.1% (5/31) unchanged and 12.9% (4/31) worsen. Tinnitus of ipsilateral ears improved or abolished in 97.0% (32/33) patients, while 83.9% (26/31) of contralateral ear got reduction or absence of loudness when cochlear implant was switched on.

As an electrical stimulation treatment method, cochlear implant has the inhibitory effect on tinnitus. However, cases of tinnitus aggravation were found, further data is still necessary before considering CI as a treatment of tinnitus.