Middle Ear Muscle Reflex and Word Recognition in "Normal-Hearing" Adults: Evidence for Cochlear Synaptopathy?

The study measured associations in one group of adults, not causes, so it cannot show that inner-ear nerve loss produced the poor word scores. The correlations were weak, and the authors said the tests are unlikely to diagnose mild or moderate cochlear neural degeneration for an individual patient. All participants had normal hearing thresholds from 0.25 to 8 kHz, so the findings do not apply to people with hearing loss, children, or patients with other ear or neurological conditions. Twenty-six participants were excluded from word-score analyses because of non-native English, test familiarity, or MoCA scores below 26 of 30. The study did not directly measure synapses or auditory nerve fibers in these participants; synaptopathy was inferred from indirect tests. Some threshold and otoacoustic emission relationships were not significant after age adjustment, so age may explain part of the pattern.

Do not conclude that middle-ear reflex testing can diagnose inner-ear nerve loss in an individual patient. The authors said these tests are unlikely to diagnose mild or moderate cochlear neural degeneration case by case, and the ear-canal SP/AP ratio was the stronger predictor.