Tinnitus most often starts when noise, aging or ototoxic drugs damage cochlear hair cells, reducing input from that frequency region.The most common starting point is cochlear hair cell damage — noise, aging, ototoxic drugs. Outer hair cell loss causes reduced input at that frequency region (a notch on the audiogram). But the tinnitus sound isn't in the ear — it's in the brain.
2 · Central gain · the brain fills in
When peripheral input drops, the auditory pathway turns up its gain, neurons become hyperexcitable and more synchronous, and this activity is perceived as sound.When peripheral input drops, the auditory pathway (cochlear nucleus to auditory cortex) undergoes gain upregulation — analogous to phantom limb pain. Neurons become hyperexcitable, synchrony increases, tonotopic maps reorganize. This excessive, synchronous neural activity is perceived as sound. This is why cutting the auditory nerve doesn't eliminate tinnitus — the source is central.
3 · Salience network · why it bothers you
Tinnitus becomes distressing only when the salience network tags it as important or threatening, and anxiety and attention then make it louder.Not all tinnitus is bothersome. It becomes distressing when the signal is tagged as important/threatening by the salience network (insula, anterior cingulate, amygdala). Anxiety, insomnia, attentional bias form a vicious cycle: more attention → louder → more anxiety. This explains why and TRT (tinnitus retraining therapy) work — they change the salience tag, not the sound.
4 · Management · no magic pill
There is no FDA-approved tinnitus drug, and management relies on sound therapy to lower contrast and on and TRT to change the response to the sound.Sound therapy (white noise, nature sounds, hearing aids): provides background input, reduces contrast. /ACT: backed by a systematic review of randomized trials (low-to-moderate certainty); changes response not the sound. TRT: 12-24 month habituation. Avoid: silence, excess caffeine/alcohol (individual), supplements claiming cure. No FDA-approved tinnitus drug.