Visual stimulation leads to activation of the nociceptive trigeminal nucleus in chronic migraine.

OBJECTIVE: The visual system has often been described to be sensitized in migraineurs, with light being perceived as aversive or even painful. One possible explanation for this altered perception is crosslinks between the visual and the trigeminonociceptive system. Visual stimulation in chronic migraineurs on the level of the brainstem might lead to enhanced activity within the spinal trigeminal nucleus (sTN) as the main site of trigeminal pain processing within this area. METHODS: Eighteen episodic migraineurs (EM), 17 chronic migraineurs (CM), and 19 healthy controls (HC) underwent one session of high-resolution brainstem imaging during which a rotating checkerboard was presented repeatedly as a visual stimulus. Data were analyzed using SPM12 and MATLAB with the classic first-level-second-level approach of SPM. Analyses of variance were used for group comparisons. RESULTS: CM showed enhanced activation within the sTN as compared to HC. In addition, we observed enhanced activity within the right superior colliculus in CM as compared to HC. When comparing all migraineurs with headaches during scanning with all migraineurs without headaches during scanning and HC, we also found the sTN to be more strongly activated during headaches. CONCLUSION: Our data provide evidence for the existence of visual-nociceptive integration on brainstem level in chronic migraineurs.

Hypothalamus as a mediator of chronic migraine: Evidence from high-resolution fMRI.

OBJECTIVE: To identify pathophysiologic mechanisms of migraine chronification using a recently standardized protocol for high-resolution brainstem imaging of trigeminal nociceptive stimulation. METHODS: Eighteen episodic migraineurs (EMs), 17 chronic migraineurs (CMs), and 19 healthy controls (HCs) underwent painful ammonia stimulation of the left nostril in a 3T MRI scanner. Functional images were acquired with a brainstem-optimized protocol for high-resolution echo-planar imaging. RESULTS: We detected a significantly stronger activation of the anterior right hypothalamus in CMs compared to HCs. To exclude the headache as a prime mediator of the hypothalamic activations, we compared all migraineurs with headaches (EMs and CMs) with all migraineurs without headaches (EMs and CMs) and HCs in a second analysis and found a more posterior region of the hypothalamus to be more activated bilaterally during headaches. CONCLUSIONS: Our data corroborate the fact that the hypothalamus plays a crucial role in the pathophysiology of migraine chronification and acute pain stage of migraineurs. While the more posterior part of the hypothalamus seems to be important for the acute pain stage, the more anterior part seems to play an important role in attack generation and migraine chronification.

Efficacy of interventions used by physiotherapists for patients with headache and migraine-systematic review and meta-analysis.

AIM: We aimed to conduct a systematic review evaluating the effectiveness of interventions used by physiotherapists on the intensity, frequency and duration of migraine, tension-type (TTH) and cervicogenic headache (CGH). METHODS: We performed a systematic search of electronic databases and a hand search for controlled trials. A risk of bias analysis was conducted using the Cochrane risk of bias tool (RoB). Meta-analyses present the combined mean effects; sensitivity analyses evaluate the influence of methodological quality. RESULTS: Of 77 eligible trials, 26 were included in the RoB assessment. Twenty trials were included in meta-analyses. Nineteen out of 26 trials had a high RoB in >1 domain. Meta-analyses of all trials indicated a reduction of TTH ( ITALIC! p < 0.0001; mean reduction -1.11 on a 0-10 visual analog scale (VAS); 95% CI -1.64 to -0.57) and CGH ( ITALIC! p = 0.0002; mean reduction -2.52 on a 0-10 VAS; 95% CI -3.86 to -1.19) pain intensity, CGH frequency ( ITALIC! p < 0.00001; mean reduction -1.34 days per month; 95% CI -1.40 to -1.28), and migraine ( ITALIC! p = 0.0001; mean reduction -22.39 hours without relief; 95% CI -33.90 to -10.88) and CGH ( ITALIC! p < 0.00001; mean reduction -1.68 hours per day; 95% CI -2.09 to -1.26) duration. Excluding high RoB trials increased the effect sizes and reached additional statistical significance for migraine pain intensity ( ITALIC! p < 0.00001; mean reduction -1.94 on a 0-10 VAS; 95% CI -2.61 to -1.27) and frequency ( ITALIC! p < 0.00001; mean reduction -9.07 days per month; 95% CI -9.52 to -8.62). DISCUSSION: Results suggest a statistically significant reduction in the intensity, frequency and duration of migraine, TTH and CGH. Pain reduction and reduction in CGH frequency do not reach clinically relevant effect sizes. Small sample sizes, inadequate use of headache classification, and other methodological shortcomings reduce the confidence in these results. Methodologically sound, randomized controlled trials with adequate sample sizes are required to provide information on whether and which physiotherapy approach is effective. According to Grading of Recommendations Assessment, Development and Evaluation (GRADE), the current level of evidence is low.