Criteria for the diagnosis of cervicogenic headache are proposed, which include unilateral head pain, symptoms and signs of neck involvement, non-clustering episodic moderate pain originating in the neck then spreading to the head, and response to root or nerve blockade; plus rarer and non-obligatory features such as autonomic disturbances, dizziness, phonophotophobia, monocular visual blurring, and difficulty swallowing.

On a world-wide basis, 84 cases of CPH were found, 59 females and 25 males: i.e., a F:M ratio of 2.36. Forty-nine cases never exhibited a remitting stage, whereas in 35 cases a history of a remitting stage was obtained, 17 cases still remaining in the remitting stage. In other words, the ratio between the chronic and the remitting stage as of today is 67:17 = 3.94. Accordingly, there seems to be a reverse relationship of the chronic versus the remitting stage, when compared to cluster headache. A maximum attack frequency even of 5-6 attacks per 24 hours seems to be consistent with a diagnosis of CPH. Nocturnal attacks occurred in 55 out of 58 cases where such information was available. An unchanging unilaterality was the rule, in that only 3 exceptions have been reported.

The clinical features of SUNCT syndrome have been reviewed in 21 patients. There were 17 men and 4 women, rendering a clear male preponderance (ratio of 4.25). The mean age at onset was around 51 years. Attacks were experienced mostly in the orbital/periorbital area and always recurred on the same side, with an erratic temporal pattern and remissions of varying lengths. Most attacks were moderate to severe in intensity and burning, electrical, or stabbing in character. The attacks were regularly accompanied by prominent, ipsilateral, conjunctival injection; tearing; and rhinorrhea or nasal obstruction. There were many precipitating mechanisms. Exclusively spontaneous attacks were described in 3 patients. The usual duration of paroxysms ranged from 10 to 60 seconds, Whereas the longest duration varied from 60 to 300 seconds. The frequency of attacks during the symptomatic periods varied from less than 1 attack daily to more than 30 per hour. In the majority of patients, supplementary examinations failed to show any notable abnormality. However, 2 patients were documented to have a symptomatic form of SUNCT, with a vascular malformation in the ipsilateral cerebellopontine angle. A variety of drugs and local anesthetic blockades, inclusive of tic douloureux drugs, were tried, but a persistent, convincingly beneficial effect was generally lacking. SUNCT syndrome is in the differential diagnosis when encountering unilateral, orbital/periorbital headache syndromes.

In the Vågå study of headache epidemiology, a search was made also for cluster headache. Of the available 18-65-year-old dalesmen, 1838 (88.6%) could be examined personally (O.S.) - 51.3% females and 48.7% males. Based on current International Headache Society criteria, cluster headache seemed to be present in seven dalesmen, one female and six males (corresponding to a total prevalence of 381 per 100 000; 95% confidence interval (CI) 153-783 per 100 000). Except for the female gender, the female case was fairly typical. In one case, there were short-lasting bouts ('minibouts'). It was felt that this also was a genuine case of cluster headache. If one excluded the latter case, there would be one female and five males [a prevalence of 106 per 100 000 for females, and 558 per 100 000 for males, giving a prevalence in the total population of 326 per 100 000 (95% CI 120-709 per 100 000)]. The confidence interval was considerable. This study therefore does not give a clear indication as to prevalence.

Skull dimensions were measured on lateral skull radiographs in 33 adult patients with MRI-verified Chiari I malformations and in 40 controls. The posterior cranial fossa was significantly smaller and shallower in patients than in controls. In the patients, there was a positive correlation between posterior fossa size and the degree of the cerebellar ectopia, which might indicate that a posterior cranial fossa which was originally too small had been expanded by the herniation of hindbrain structures at an early stage. Pyramidal signs and cerebellar symptoms and signs, which may be due to compression of neural structures, were associated with a large degree of ectopia and a relatively large posterior cranial fossa. Syringomyelia and headache, which may be due to the valve action of the herniated cerebellar tissue, were not associated with a particularly large posterior fossa or herniation. No special clinical presentation was associated with a very small posterior cranial fossa, which may indicate that a small posterior cranial fossa per se has little or no clinical significance, although it may be the primary developmental anomaly.