A Cochrane review «Tinnitus Retraining Therapy (TRT) for tinnitus»1 «Phillips JS, McFerran D. Tinnitus Retraining Therapy (TRT) for tinnitus. Cochrane Database Syst Rev 2010;(3):CD007330. »1 included one study with 123 participants with tinnitus. They were recruited from a cohort of US military veterans with the predominance of males. In this study outcome data for tinnitus severity were presented using 3 instruments (Tinnitus Handicap Inventory (THI), Tinnitus Handicap Questionnaire (THQ), Tinnitus Severity Index (TSI)) for patients in 3 groups: tinnitus being a moderate, big or very big problem. At 18 months, improvements for the 3 groups in the 3 scores (TRT versus TM) were respectively: 'moderate problem' - THI: 18.2 versus 4.6, THQ: 489 versus 178, TSI 7.5 versus 1.6; 'big problem' - THI: 29.2 versus 16.7, THQ: 799 versus 256, TSI: 12.1 versus 6.7; and 'very big problem' - THI: 50.4 versus 10.3, THQ; 1118 versus 300, TSI: 19.7 versus 4.8. The trial showed Tinnitus Retraining Therapy (TRT) to be more effective than a tinnitus masking (TM) approach.
Comment: The quality of the evidence is downgraded by study quality (inadequate allocation concealment), imprecise results (limited study size for each comparison) and indirectness of evidence (differences in studied patients).