Table 1.

Categories of TRT mixing point-level close to the place where the sound from the instrument blends with the tinnitus.

Category	0	I	II	III	IV
Tinnitus	Small problem	Serious problem	Serious problem	Present/absent	Present/absent
Hyperacusis	Absent	Absent	Absent	Present	Present/absent
Noise exposure	No prolonged effect	No prolonged effect	No prolonged effect	No prolonged effect	Prolonged effect
Subjective Hl	Absent	Absent	Significant	Irrelevant/ significant	Irrelevant/significant
Main problem	Tinnitus	Tinnitus	HL	Hyperacusis	Tinnitus or hyperacusis
Treatment	Avoid silence recommendation	Noise generators set at mixing point	Hearing aids with/without noise generators set below mixing point	Noise generator firstly set at hearing threshold then gradually increased to mixing point	Noise generators firstly set at hearing threshold then gradually increased to mixing point