Auditory evoked potentials--the cochlear summating potential in detection of endolymphatic hydrops

Area of Science:

• Otolaryngology
• Neuroscience
• Audiology

Background:

• Summating potential (SP) enlargement is a potential indicator for Meniere's disease.
• Previous studies suggested a high incidence of SP enlargement in Meniere's disease.
• Clinical populations in prior studies may have been preselected, potentially inflating SP enlargement rates.

Purpose of the Study:

• To re-examine the incidence of SP enlargement in clinically defined Meniere's and cochlear ears using an expanded clinical and normative SP amplitude series.
• To assess the relationship between SP enlargement and varying degrees of high-frequency hearing loss in Meniere's disease diagnosis.

Main Methods:

• Analysis of an expanded clinical and normative SP amplitude series.
• Comparison of SP enlargement incidence in Meniere's disease patients versus a control group.
• Correlation of SP enlargement with different high-frequency hearing loss levels (4-8 kHz).

Main Results:

• The overall incidence of SP enlargement in the expanded series was 56%, lower than a previous study's 68%.
• SP enlargement is less reliable for Meniere's diagnosis in cases of normal/near-normal hearing (≤25 dB HL at 4-8 kHz).
• SP enlargement occurs infrequently with severe high-frequency hearing loss (>70 dB HL), but shows a 71% "hit rate" in the mid-range (25-70 dB HL).

Conclusions:

• The SP enlargement test for Meniere's disease requires careful interpretation alongside high-frequency hearing levels.
• The diagnostic utility of SP enlargement is most significant in the moderate high-frequency hearing loss range.
• Broader patient selection in the current study may explain the lower observed SP enlargement incidence compared to preselected cohorts.