Researchers Identify Signal Components Associated With Unpleasantness Among Patients With Migraine

Sound hypersensitivity is highly prevalent in migraine, with 70% to 80% of patients with migraine being affected by the side effect. Hoping to clarify the pathogenic mechanism that underlies migraine attacks triggered by sound, researchers have identified specific signal components associated with unpleasantness for patients with migraine.

The findings come from a study of 100 participants, 50 of which had migraine. Among these participants with migraine, 58% displayed sound hypersensitivity. The other 50 participants were healthy controls who had no history of migraine.

The researchers included 20 types of environmental sounds that participants would likely hear on a daily basis that spanned across 4 categories: animal sounds, natural sounds, emotional sounds, and excessive noise/sirens. Sounds included a cat mewing, 2 to 3 sparrow chirping, children talking, dogs barking, waves crashing, running water, church bells, fireworks, a car horn, an ambulance siren, and construction work.

Participants listened to a single sound stimulus and then had 15 seconds to report how pleasant or unpleasant the sound was using a 9-point scale ranging from -4 (extremely uncomfortable) to 4 (extremely comfortable).

“Participants provided a median rating of -1 or lower to all sounds considered to be excessive noise/sirens, suggesting that stimuli in this category caused greater discomfort than did sounds in the other categories,” wrote the researchers. "Conversely, emotional sounds tended to be rated more highly than sounds in other categories, with the 75th percentile reaching 2 in some cases.”

Compared with controls, participants with migraine had lower median ratings for approximately half of the sound types, with the most significant differences observed for sparrow calls, evening cicada calls, car horns, crossing bells, ambulances, and police cars. The researchers noted that different sounds in the same category often carried different effect sizes.

According to the researchers, there was a tendency for participants with migraine rating sounds lower than controls did when their signal component at approximately 400 Hz was smaller in amplitude and less variable over time.

“In fact, the 400 Hz band was very weak for cat calls, evening cicada calls, ambulances, and police cars, all sounds with large effect sizes between migraineurs and controls,” explained the researchers. They add that these findings highlight the importance of certain frequency bandwidths and temporal properties.”

Reference:

Ishikawa T, Tatsumoto M, Maki K, Mitsui M, Hasegawa H, Hirata K. Identification of everyday sounds perceived as noise by migraine patients. Internal Medicine. doi: 10.2169/internalmedicine.2206-18.