Some playlists promise focus through special tones. You may see words such as bilateral or binaural. Knowing what they mean can help you choose what to listen to.
A sound that moves between ears
Bilateral audio moves a sound from your left ear to your right, then back again. Headphones make that shift easier to hear.
Some people like the pattern. Others find it distracting. How it feels can change with the volume, how tired you are and what is around you.
Two tones that seem to make a beat
With binaural beats, each ear hears a slightly different tone. Your brain may hear a beat at the gap between them.
For example, one ear hears 200 hertz and the other hears 210 hertz. You may hear a beat of 10 hertz. Hertz counts how many times something repeats each second. This shows how it works. It is not advice about which tones to use.
The sound does not need to move from side to side. That is what makes this different from bilateral audio.
What a label can tell you
Tracks may use names such as alpha or theta. These names also describe ranges of brain activity. A matching name does not prove that a track will put your brain in that state.
A 2023 review found mixed evidence that the brain follows the rhythm of binaural beats. Studies of attention also have mixed results. In a small study of young people with ADHD, attention-test results did not clearly improve compared with the other group.
What about trauma therapy?
A therapist may use sound that moves between ears during EMDR. EMDR is a full treatment for post-traumatic stress disorder, or PTSD. The therapist checks your needs, helps you prepare and guides the work.
Research on the full therapy does not prove that a sound track alone treats trauma.
Notice how it feels
Start at a low volume and keep an easy way to pause. Does it feel good? Is it tiring? Does it draw your focus away? You can choose quiet.
You do not need to bring up painful memories while listening. If distress or sleep problems keep happening, ask a health professional for help.