Auditory function in adrenomyeloneuropathy

Area of Science:

• Neuroscience
• Audiology
• Genetics

Background:

• Adrenomyeloneuropathy (AMN) is a rare genetic disorder affecting the nervous system and adrenal glands.
• Hearing impairment can be a symptom of AMN, but its audiological profile is not fully understood.
• Auditory pathway integrity is crucial for communication and quality of life.

Purpose of the Study:

• To investigate auditory pathway function in patients with adrenomyeloneuropathy (AMN).
• To characterize auditory brainstem responses (ABR), acoustic reflexes, and masking level differences (MLD) in AMN.
• To correlate audiological findings with the clinical presentation of AMN.

Main Methods:

• Auditory brainstem responses (ABR) were recorded in 29 AMN patients.
• Ipsilateral and contralateral acoustic reflexes were assessed.
• Masking level difference for speech (MLD) was measured.
• ABR wave latencies and reflex parameters were analyzed.

Main Results:

• All patients showed abnormalities in ABR components, with Waves V and III most affected.
• Interpeak latency intervals (I-III, III-V, I-V) were abnormal in a majority of male and female AMN patients.
• Contralateral acoustic reflexes were abnormal in ~50% of ears, and ipsilateral reflexes in 25%.
• MLDs were significantly reduced in 72% of patients.
• Early ABR components (Waves III and I) were the initial sites of impairment.
• Word recognition in quiet was largely unaffected.
• Patients often denied significant hearing difficulties despite objective ABR abnormalities.

Conclusions:

• The auditory pathway, particularly early ABR components, is frequently affected in AMN.
• Objective audiological testing reveals significant hearing pathway dysfunction in AMN patients, often unperceived by the patients.
• These findings highlight the importance of comprehensive audiological assessment in AMN management.