(PP1320) Novel Investigation of the Effects on Hearing in a Preclinical Migraine Model Using Tone-Burst Auditory Brainstem Response

Lead Presenter(s)

MH

Megan Huelsing

Audiology Graduate Student
Missouri State University, United States

Presenter(s)

Wafaa Kaf, MBBCh; MSc; PhD

Professor
Missouri State University
Springfield, Missouri, United States
Paul L. Durham, PhD

Distinguished Professor, Director
Missouri State Univesity
Springfield, Missouri, United States

Contributor(s)

SW

Sara Woodman

Abstract: Migraine is the most common neurological disease, is characterized by extreme headaches, and is accompanied with changes in hearing sensitivity, which is reported as one of the most bothersome symptoms and negatively influences a migraineurs quality of life. The goal of this study was to use an established preclinical model of chronic migraine to investigate changes in hearing sensitivity by measuring neural activity of the auditory nerve in a rat model. Results from this study provide the first evidence to our knowledge of changes in ABR hearing sensitivity and latency in a preclinical chronic migraine model.

Summary: Migraine is the most common neurological disease and is characterized by an extreme headache that can last from 4 to 72 hours and is accompanied with photophobia (sensitivity to light), phonophobia (persistent, abnormal, and unwarranted fear of sound), and nausea. In human studies, changes in hearing sensitivity are reported as one of the most bothersome symptoms associated with this disorder and negatively influence quality of life for these individuals. Clinically, migraine, which is more prevalent in women, is commonly associated with phonophobia and hyperacusis (abnormally strong reaction to normally non-painful sounds), yet the underlying mechanisms are not well understood. The goal of this study was to use an established preclinical model of chronic migraine to investigate changes in hearing sensitivity by measuring neural activity of the auditory brainstem before and post migraine. To induce a chronic migraine state within the trigeminal system, male and female Sprague Dawley rats were subjected to three known human risk factors including neck muscle tension and REM sleep deprivation that promote latent sensitization, and exposure to a pungent odor, which acts as a trigger to stimulate trigeminal activation and pain signaling. Tone burst auditory brainstem responses (ABRs) were measured using the Duet Intelligent Hearing System to determine effects of migraine pathology on brainstem auditory pathways in six rats at baseline (naïve) condition and post migraine condition. Tone burst ABR was recorded in each ear to 4 kHz, 12 kHz, 22 kHz, and 32 kHz stimuli. Suprathreshold ABRs were recorded at 80 dB SPL to assess waveform morphology and latency. To determine the threshold, ABR was recorded at 50 dB and 20 dB and then at 30 dB or 10 dB depending on the response at 20 dB. The threshold value was defined as the lowest intensity to elicit a reliable wave II, the largest wave in rats. Results showed that at baseline (naïve condition), at 80 dB ABR morphology exhibited the presence of waves I, II, and III, with wave II being the largest wave. As frequencies increased from 4 kHz to 32 kHz, latencies decreased and amplitudes increased with larger amplitude in the right ear than the left ear, and with decreased ABR thresholds at higher frequencies (22 kHz and 32 kHz) than lower frequencies (4 kHz and 12 kHz). After induction of migraine pathology, changes were observed including increased latency in the left ear at 22 kHz and 32 kHz and a 10-20 dB increase in the right ear thresholds at 32 kHz. Results from this novel study provide to our knowledge the first evidence of changes in high frequency hearing sensitivity and ABR latency in a preclinical chronic migraine model.

Learning Objectives:

Upon completion of this session, the participant will be able to identify the characteristics of ABRs in rats and describe the effect of chronic migraine on hearing thresholds.