In our patient surveys on this subject, and communicating with a number of sufferers, head-ache is described as a very common feature. I had not including it as a critical feature, as head-ache is a very common and nonspecific experience that everyone gets. With more reflection, I believe it is worth adding in as the type of head-ache or head-pain may be quite distinctive.
Head pain (early stage GDD onset). Headache is both a very common occurrence and also shows tremendous variability, so it is difficult to pin down the exact type of head-ache that may characterize GDD. GDD sufferers describe it as a head pain, and unlike any other type of head-ache they have previously experienced. These two properties provide differentiating features for this entity. Some describe it as a burning pain and also as an extreme tightness feeling (like a tight bathing cap on their head). If we categorize two main categories/sources of pain as: 1)immune cell reaction to deposition of Gd and 2) neuropathy; the skull, skin and skin substrate, and extensive scalp innervation, all occur in that location and in close proximity to eachother. So it is likely the pain may arise from either one in some individuals, or from both in others, which would also then account for the variability of descriptions. Another issue is that localization may be described as superficial or deep, but it is well recognized with head-aches (and also other types of pain) that the pain may feel deep in location, but is actually referred there from a superficial origin (referred pain), so 'deep' head-aches are generally from a superficial scalp origin.