Differential effects of glucocorticoids on human auditory perception

Area of Science:

• Neuroendocrinology
• Auditory Neuroscience
• Sensory Perception

Background:

• Adrenal cortex hormones, glucocorticoids and mineralocorticoids, are known for endocrine stress responses.
• Emerging evidence suggests adrenal corticoids also modulate central nervous system functions, potentially altering sensory thresholds.

Purpose of the Study:

• To investigate the effects of specific glucocorticoids (hydrocortisone and dexamethasone) on auditory perception in healthy volunteers.
• To examine if these effects differ based on the time of day, considering circadian variations in brain corticosteroid receptors.

Main Methods:

• Two double-blind, placebo-controlled crossover studies were conducted.
• Auditory functions assessed included stapedial reflexes, pure tone and speech audiometry, and brainstem electric response audiometry.
• Studies were performed in the morning (Study I) and evening (Study II) to account for circadian rhythms.

Main Results:

• Treatment effects of glucocorticoids on auditory perception varied significantly depending on the time of day.
• A differential effect was observed for contralateral stapedial reflexes between hydrocortisone and dexamethasone.
• These findings align with previous research on gustatory stimuli, indicating a broader role for glucocorticoids in sensory modulation.

Conclusions:

• Glucocorticoids appear to modulate sensory perception, specifically auditory processing.
• The time of day influences the impact of glucocorticoids on auditory function.
• These findings support the hypothesis that adrenal corticoids play a role in central nervous system modulation of sensory input across different modalities.