PLOD1 and Headache: Finally, the literature-reported CEH with pain restricted in a line-shaped area (Cooper et al. 2007) may, in fact, be LH but not CEH, as the exclusive diagnostic measure was anesthetic blockades at upper cervical spinal nerves (Cooper et al. 2007), and the anesthetic blockade of the branch of upper cervical spinal nerves, occipital nerve, was also effective in many other types of headaches including migraine headache (Dilli et al. 2015; Inan et al. 2015).