The eardrums move when the eyes move: A multisensory effect on the mechanics of hearing.
Level 4 - case-series / case-control
Small exploratory laboratory physiological study in humans and non-human primates.
PubMed 29363603 · doi:10.1073/pnas.1717948115
What was done
Ear canal microphone recordings were used to measure eardrum movement in humans (n = 16 subjects, 19 ears) and monkeys (n = 3 subjects, 5 ears) during saccadic eye movement tasks toward visual targets in the absence of acoustic stimuli.
What was found
Eardrums showed oscillatory motion (termed eye movement-related eardrum oscillations, or EMREOs) accompanying eye movements. In humans, oscillation onset preceded saccades by as early as 10 ms, whereas in monkeys it coincided with saccade onset. The amplitude and phase of the oscillations varied with the direction and horizontal amplitude of the saccade and persisted through the saccade into steady fixation. The abstract reports no numerical effect sizes or statistical test metrics beyond the 10 ms timing.
Why it matters
This study shows that multisensory visual-auditory interactions occur mechanically at the peripheral eardrum before central auditory processing, providing a potential mechanism for how the brain coordinates auditory and visual spatial maps during gaze shifts.
Limits
The study evaluated very small samples (16 humans and 3 monkeys). The abstract provides limited quantitative outcome measures, and direct perceptual consequences on auditory localization were hypothesized rather than experimentally verified.