A 2015 review examined whether CI implantation to treat people with bilateral hearing loss had any effect on tinnitus. This review found the quality of evidence to be poor and the results variable: overall total tinnitus suppression rates varied from 8% to 45% of people who received CI; decrease of tinnitus was seen in 25% to 72%, of people; for 0% to 36% of the people there was no change; increase of tinnitus occurred in between 0% to 25% of patients; and, in between 0 and 10% of cases, people who did not have tinnitus before the procedure, got it.