Changes in the hippocampal volume in chronic migraine, episodic migraine, and medication overuse headache patients.

Background and purpose:

Hippocampi are the structures located in the medial depths of both temporal lobes, mainly responsible for memory, navigation and regulation of emotions, and activated during the processing of pain and the modification of nociceptive stimuli. Chronic pain is thought to have stress-like detrimental modulatory effects on the hippocampal neurogenesis, and adults with chronic pain have been showed to have lower hippocampal volumes. The present study aims to show the relationship between headaches and hippocampal volume by comparing the right, left and total hippocampal volumes of patients with Episodic Migraine (EM), Chronic Migraine (CM) and Medication Overuse Headache (MOH) to those of the healthy control group using the Magnetic Resonance Imaging (MRI) technique, also by looking into the correlation between the number of painful days and attacks and the current hippocampal volumes.

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Methods:

A total of 30 patients (10 EM, 10 CM, 10 MOH) from 18 to 45 years of age diagnosed with migraine and also followed up by the neurology outpatient clinic from February to May 2022 and 30 healthy volunteers of similar ages and sexes to the patient group were included in the study. In addition to the routine cranial MRI protocols of all the participants, further cranial images were taken with the addition of the T1W 3D FSPGR sequence adjusted to the hippocampal body in the coronal plane and covering the whole brain. Hippocampal volumes were measured manually.

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Results:

There were 27 females and 3 males in the patient group versus 28 females and 2 males in the control group, and no statistically significant differences in age and sex were found between the groups. The control group had higher average right, left and total hippocampal volumes than the whole patient group, but only the total hippocampal volume was significantly different between the groups. There was a negative correlation between the number of painful days and the measured right hippocampal and total hippocampal volumes; however, the measured values were not statistically significant. 

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Conclusion:

It was concluded that the changes in the hippocampal volume in migraine might be associated with the pain characteristics of the disorder. 

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