Migraine is a clinical diagnosis. This study describes important clinical signs which would improve the diagnostic accuracy of migraine. It was conduced in a group of 709 patients presented with headache.
Pointing right or left side of forehead (signs A and B) was statistically significantly associated with the migraine group when the patient describes his or her headache. Furthermore, sign A was more commonly associated with unilateral, severe headache which lasted for a longer period of time. However sign B was more commonly associated with unilateral, severe headache only. Sign C (Pointing both sides of forehead) was more common in patients who had bilateral headache in both migraine and non-migraine groups. Keeping the head on the table (Sign F) was significantly associated in patients with non-migraine headache.
These signs have not been described in previous studies apart from the after image following fundoscopy (De Silva 2001) and the digiti quinti sign (Vincent 2009) which has limitations because it can be only used in hemiplegic migraine.
These results show that pointing right side or left side of forehead as a gesture is a sign of migraine which is common mainly in unilateral severe headache. Although both sign A and B should be having the equal significance when considering in the context of the duration of the attack, according to the statistical analysis only sign A is significant. Although it is difficult to explain this paradox, handedness and the cerebral dominance may be a factor. In our study handedness was not investigated.
When considering the relationship of Sign A and B (here in after referred to as AM sign of migraine [AM-Aruna Munasinghe] for the sake of easiness) taken together with its strong statistical significance with the severity, it is reasonable to propose that so called AM sign can be considered as a measure of severity as well.
It is still interesting to find that both sign A and B (AM sign) is positive with aphasia as an aura. We are not in a position to explain this phenomenon. As we have mentioned above it may be related to handedness of the people. (Whether they are right handed or left handed.)
This study was performed by using an interviewer administered questionnaire. Although all the interviewers were properly trained by the principal investigators it is impossible to believe that they will administer the questionnaire with the same accuracy as there is always a bias factor. It is important to note that person who analyzed the data is completely blind with regard to the physical signs.
Although we have done a detailed literature review we could not find any comparable or similar study. Hence this study is a unique one. For the sake of understanding this can be compared with the pointing sign in appendicitis. However in appendicitis the sign is elicited by the examiner whereas our pointing sign (AM sign) is not elicited in the same manner. Instead the sign itself is shown by the patient as a gesture. The examiner only observes the gesture and interprets it as a sign. Corrigan’s sign in aortic incompetence is a reasonable comparison to so called ‘AM’ sign. The importance of this sign lies in the fact that it shows a very strong statistical significance in the clinical setting. Therefore the signs we have described will be very useful in making a positive diagnosis of migraine which is often diagnosed by exclusion by many clinicians, despite international headache society criteria. It is important to stress that sign F (arbitrarily named as SM sign) has a strong negative predictive value thus helping ruling out migraine in clinical diagnosis of headache.
There may be cultural/regional variations of patients with headache, communicate with their doctor. If pointing sign could be confirmed in a study in another country this would support the universality of the finding and the generalization of the conclusions.
In conclusion pointing right or left side of forehead when the patient describes his or her headache is a characteristic sign of migraine. Keeping the head on the table during an attack of headache is not a characteristic sign of migraine.