A Study of the Functional, Metabolic and Microstructural Brain Changes in Patients with Migraine without Aura

Background: Migraine is a very common disease. Studying the pathological changes in the brain is important for understanding the mechanisms underlying migraine headache. Previous research work has given conflicting results. This study aimed to investigate the functional, metabolic and microstructural changes in the brain of migraine patients without aura.

Methods: This study included 42 migraine patients without aura in the interictal period and 11 age and sex matched controls. All participants were subjected to clinical assessment, assessment of the habituation to visual evoked potentials, assessment of the peak metabolic ratios by H-MRS and diffusion tensor imaging of the brain to test for regional microstructural changes.

Results: The amplitudes of VEPs showed significant reduction in control subjects (P < 0.01), but not in migraine patients after repeated stimulation and significant increase in migraine patients compared to controls (P < 0.01). H-MRS showed significant decrease of NAA/Cr (P < 0.01) and increase of Mi/NAA (P < 0.001) and Cho/Cr (P < 0.05) PMRs in the thalamus and occipital lobes in migraine patients compared to controls. DTI showed significant changes in the FA, AD, MD, RD values in the thalamus, occipital lobe and insula in migraine patients indicating microstructural changes in these areas. All changes showed significant correlation with the intensity, frequency and duration of migraine episodes, but not with the duration of migraine disease.

Conclusion: Migraine patients without aura showed increased excitability to visual stimulation and significant metabolite and microstructural brain changes that correlated with the severity, not the duration of the disease. These changes need to be confirmed in a large scale longitudinal studies.