Is there a brainstem generator of chronic daily headache?

Using BOLD-fMRI we have previously documented activation of the red nucleus (RN) and substantia nigra (SN) during spontaneously and visually activated migraine headache. These observations prompted us to study brainstem function in chronic daily headache patients using high-resolution magnetic resonance imaging (MRI) techniques. Seventeen chronic daily headache (CDH) patients, ten episodic migraine (EM) patients and fifteen controls (N) were imaged with a 3 tesla MRI system. For each subject, the relaxation rates R2, R2* and R2' were obtained for RN and SN. There was a significant decrease in R2' and R2* values for RN and SN in CDH compared to N and EM groups (p < 0.05), but no significant difference between the N and EM groups. A decrease in R2' and R2* indicates reduced deoxyhemoglobin and hence persistent activation of the RN and SN in CDH patients most likely secondary to ongoing headache at the time of study. The imaging data provide objective evidence of disturbed central nervous system function in CDH.