Overview
- A PLOS ONE study that tested 28 self‑identified hum hearers found little evidence of unusually sensitive low‑frequency hearing and no measurable low‑frequency oto‑acoustic emissions, leading authors to favor a subjective low‑frequency form of tinnitus for most cases.
- The team used low‑frequency threshold tests and ear‑canal microphones to check two leading external‑sound theories — hyper‑acute hearing and inner‑ear emissions — and both tests returned negative results for the majority of participants.
- Participants reported a median matched pitch near 50 Hz and high levels of distress, with many saying family members could not hear the sound and that it disrupted sleep and daily life.
- The study's sample was small and self‑selected from a social media support group, controls were younger, and many frequency matches were done at home, so the authors caution results cannot rule out external sources for a minority of sufferers.
- The research shifts attention toward expanding audiology work on low‑frequency tinnitus, improving lab‑based low‑frequency measurement, and running larger or relocation studies to separate internal percepts from real external noise sources.