Study of auditory pathways in type 1 diabetes mellitus through brainstem auditory evoked potentials and contralateral acoustic reflex.
Luciene da Cruz Fernandes, Caio Leônidas Oliveira de Andrade, Luis Fernando Fernandes Adan and 1 others
PMID 37194912WHAT IT FOUND
In T1DM patients with normal standard hearing thresholds, auditory brainstem response timing was slower and left-ear acoustic reflexes occurred at lower intensities than in controls.
This suggests subclinical auditory pathway changes, but the study did not test treatment.
Key findings
01Auditory brainstem absolute latencies for wave III in the right ear and wave V in both ears were longer in T1DM patients than in controls.
02Acoustic reflex thresholds were elicited at lower intensities in the left ear at 0.5 and 1 kHz in T1DM patients.
03T1DM patients had elevated tonal hearing thresholds at 4 kHz in the right ear and at 2 kHz and 4 kHz in the left ear compared with controls.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study included only people whose standard hearing thresholds were within 20 dB HL, so it does not describe auditory pathway changes in patients who already have clinically detected hearing loss. It was cross-sectional and compared groups at one time point, so it cannot show that diabetes caused the auditory changes or how they would progress. The sample was small and from one centre, with 32 T1DM patients and 20 controls, which limits how widely the findings can be applied. Most T1DM participants had poor metabolic control, with 84% inadequate capillary glucose and 90.0% elevated glycated hemoglobin, so the results may reflect a poorly controlled population rather than all T1DM patients. The participants were mainly young adults, with mean ages of 21.0 ± 6.1 years in the T1DM group and 22.7 ± 7.6 years in controls, so the findings may not apply to older adults. The authors note a shortage of comparable studies and different protocols, which makes it hard to normalise these BAEP and acoustic reflex measures.
The easy way to misread this
Do not conclude that T1DM causes hearing loss or that these tests should change treatment. The participants were selected for normal hearing thresholds, the study was cross-sectional, and no intervention was tested.