Stapedius reflex and brainstem auditory evoked responses in multiple sclerosis patients

Area of Science:

• Neuroscience
• Audiology
• Clinical Neurology

Background:

• Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system.
• Auditory pathway involvement is common in MS, impacting hearing function.
• The stapedius reflex (SR) and brainstem auditory evoked potential (ABR) are sensitive electrophysiological measures of auditory pathway integrity.

Purpose of the Study:

• To investigate the prevalence and correlation of stapedius reflex (SR) and brainstem auditory evoked potential (ABR) abnormalities in multiple sclerosis patients.
• To assess the relationship between these electrophysiological findings and clinical disability.
• To explore the intercorrelation between SR and ABR abnormalities.

Main Methods:

• Recorded SR (including adaptation) and ABR in 53 definite multiple sclerosis patients (Hyllested grade 1-4).
• Assessed peripheral hearing using pure-tone audiogram and speech threshold.
• Analyzed correlations between SR, ABR, and clinical data.

Main Results:

• ABR was abnormal in 40% of patients; SR was abnormal in 11% and borderline in 21%.
• Peripheral hearing was normal in most cases (44/53).
• SR and ABR abnormalities showed limited correlation with clinical disability but a better, though not implicit, correlation with each other. Bilateral ABR abnormalities were associated with higher SR abnormality rates.

Conclusions:

• Electrophysiological auditory testing, particularly ABR, reveals significant abnormalities in a substantial proportion of MS patients.
• SR abnormalities are less frequent but may indicate more widespread auditory pathway dysfunction when present with bilateral ABR issues.
• Further research is needed to clarify the precise relationship between SR, ABR, and MS pathophysiology.