Study: 'The Hum' likely caused by inner-ear tinnitus
SkimNews Take
Attributing The Hum to internal auditory processing reframes a global mystery as individual pathology, redirecting the remediation path from environmental monitoring toward clinical audiology.
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- NTNU researchers tested 28 people in Germany who reported hearing an unexplained hum, finding that only 2 of 28 had above-average sensitivity at certain low frequencies — undermining the hypothesis that sufferers detect sounds others cannot.
- The PLOS One study also ruled out oto-acoustic emissions — faint sounds the inner ear naturally produces and can measure with a sensitive microphone — leaving subjective low-frequency tinnitus as the leading explanation for most cases.
- The Hum affects an estimated 2-4% of people worldwide and was first widely reported in Bristol, England in the mid-1970s before spreading to the US, Canada, Australia, New Zealand, South Africa and several European cities.
- Professor Markus Drexl, the NTNU hearing researcher who led the study, noted that hearing science is built mainly on higher-frequency research, leaving the auditory system's processing of low-frequency sound and infrasound (below 20 Hz) poorly understood.
- Canadian teacher Glen MacPherson launched the World Hum Map and Database Project in 2012 after first hearing the sound on Canada's west coast, creating a crowdsourced record of global reports.
- The phenomenon is more commonly noticed inside buildings at night, can cause physical discomfort or illness, and is typically heard only by one person in a given room.
Why it matters: This reframes The Hum from an environmental mystery into a likely neurological one — most of the estimated 2-4% of people affected worldwide may be experiencing low-frequency tinnitus rather than detecting external sources, meaning mechanical, industrial, or covert explanations can be set aside for most cases. The NTNU team also flagged that hearing science itself lacks basic understanding of how the auditory system processes low-frequency sound.
