Commentary on 2022 guidelines on clinical trial design in cluster headache and further suggestions.

BACKGROUND: New guidelines for cluster headache clinical trials were recently published. We welcome these new guidelines and raise additional considerations in trial methodologies. MAIN BODY: We present non-inferiority trials to overcome ethical issues with placebo use, and additionally discuss issues with trial recruitment. CONCLUSIONS: We highlight some possible issues and solutions to be considered with the recently published cluster headache trial guidelines.

Review of Tolosa-Hunt Syndrome, Recent Updates.

PURPOSE OF REVIEW: We aim to present diagnostic considerations and management insights on Tolosa-Hunt syndrome. We highlight recent controversies in this field and emerging literature. RECENT FINDINGS: The diagnostic categorization of Tolosa-Hunt syndrome remains controversial, with imaging negative cases described in the literature and an increasing literature of secondary causes falsely diagnosed as Tolosa-Hunt syndrome. Response to steroids can fulfill diagnostic criteria, but newer management strategies are available in treatment-resistant patients, such as steroid-sparing agents or radiotherapy. Tolosa-Hunt syndrome has become controversial; the entity of granulomatous inflammation of the cavernous sinus and possible extension into orbital fissure and posterior orbit of late has been re-evaluated. Recent case series and reviews have outlined multiple false positive (neoplasm or infection) and negative (no imaging findings) diagnoses. In the future, when assessing whether a patient has this entity, we caution readers to closely follow patients for secondary causes and consider this entity in differential even if MRI is non-revealing. Additionally, biopsy should be regarded as a gold standard for diagnosis and utilized, especially in uncertain cases. The diagnostic categorization of Tolosa-Hunt syndrome may need reconsideration in future versions of the ICHD.

Effects of acute and preventive therapies for episodic and chronic cluster headache: A scoping review of the literature.

BACKGROUND: Cluster headache is the most common primary headache disorder of the trigeminal autonomic cephalalgias, and it is highly disabling. OBJECTIVE: We undertake a scoping review to characterize therapies to prevent and acutely treat cluster headache, characterize trial methodology utilized in studies, and recommend future trial "good practices." We also assess homogeneity of studies and feasibility for future network meta-analyses (NMAs) to compare acute and preventive treatments for cluster headache. METHODS: A priori protocol for this scoping review was registered and available on Open Science Forum. We sought studies that enrolled adult patients with cluster headache as identified by accepted diagnostic criteria. Both randomized controlled trials (RCTs) and observational studies (with a control group) were included. The interventions of interest were medications, procedures, devices, surgeries, and behavioral/psychological interventions, whereas comparators of interest were placebo, sham, or other active treatments. Outcomes were predefined; however, we did not exclude studies lacking these outcomes. A systemic search was conducted in Ovid Medline, Embase, and Cochrane. We performed a targeted search for conference abstracts from journals prominent in the field. RESULTS: We identified 56 studies: 45 RCTs, four studies only available in clinical trial registries, and seven observational studies. Of the 45 RCTs, 20 focused on acute therapies and 25 on preventive therapies. Overall, we determined that it is feasible to pursue a NMA for acute therapy focusing on 15 or 30-min headache reduction for acute trials, as we identified 11 trials in the combined population of patients with either episodic or chronic cluster headache (2 trials in populations with chronic cluster headache were also found). For preventive therapy of cluster headache, we identified trials with common outcomes that may be considered for NMA, however, as these trials had differences in treatment effect modifiers that could not be corrected, NMAs appear infeasible for this indication. We identified new studies looking at noninvasive vagal nerve stimulation, sphenopalatine ganglion stimulation, prednisone, and oxygen published since the most recent systematic review in the field, although these acute treatments were previously identified as effective. However, for calcitonin gene-related peptide (CGRP) monoclonal antibodies, galcanezumab demonstrated effectiveness in episodic cluster headache, but a lack of effectiveness in chronic cluster headache, and fremanezumab was not effective for episodic nor chronic cluster headache. This finding highlights that CGRP monoclonal antibodies may not show a class effect in cluster headache prevention and need to be considered individually. CONCLUSIONS: We describe the treatment landscape of cluster headache for both acute and preventive treatments. Last, we present the NMAs we will undertake in acute therapies of cluster headache.

Network meta-analysis of therapies for cluster headache: Effects of acute therapies for episodic and chronic cluster.

OBJECTIVE: We used network meta-analysis (NMA) to characterize the relative effectiveness and harms of acute treatment options for cluster headache. BACKGROUND: There are few evidence-based acute treatments available for cluster headache. As most treatments were compared only against placebos in clinical trials, few head-to-head comparisons of treatments are available. METHODS: An a priori registered scoping review was performed to identify randomized controlled trials evaluating treatments in adult patients (>18 years old) with cluster headache per accepted diagnostic criteria. Bayesian NMAs were performed to compare treatments in terms of headache relief at 15 or 30 min, and also the occurrence of adverse events. We report odds ratios (ORs) of relative treatment effects along with corresponding 95% credible intervals (CrIs), as well as measures of treatment ranking. RESULTS: A total of 13 randomized controlled trials informed NMAs. We found high flow oxygen to be the most effective therapy for headache response at 15 and 30 min (OR 9.0, 95% CrI 5.3 to 15.9 vs. placebo), with injectable sumatriptan demonstrating the next highest effect (OR 6.4, 95% CrI 3.75 to 11.1 vs. placebo). High flow oxygen was also more effective than low flow oxygen (OR 2.55, 95% CrI 1.13 to 5.8), nasal spray zolmitriptan (OR 3.75, 95% CrI 1.72 to 8.4), octreotide (OR 4.5, 95% CrI 1.64 to 12.5), and non-invasive vagal nerve stimulation (nVNS; OR 5.2, 95% CrI 2.29 to 11.9). Sumatriptan injectable was also effective for headache relief and was found to be better than nasal spray zolmitriptan (OR 2.67, 95% CrI 1.21 to 5.9), octreotide (OR 3.20, 95% CrI 1.17 to 8.8), and nVNS (OR 3.69, 95% CrI 1.63 to 8.4). Octreotide (OR 4.1, 95% CrI 1.71 to 10.5) and sumatriptan (OR 2.40, 95% CrI 1.39 to 4.2) were associated with greater risk of adverse events compared to placebo, while other treatments did not demonstrate increased risk. When focusing on patients with episodic cluster headache, nVNS was significantly better than placebo (OR 4.9, 95% CrI 1.89 to 14.1). CONCLUSIONS: Our findings suggest that high flow oxygen is more efficacious when compared to low flow oxygen for headache relief. When low flow oxygen fails in patients who can tolerate oxygen, increased flow rates should be tried. Additionally, high flow oxygen is likely more effective than zolmitriptan nasal spray, nVNS, and octreotide. Sumatriptan injectable is more likely to be effective when compared to zolmitriptan nasal spray, octreotide, and nVNS.

Chronic Migraine - Evolution of the Concept and Clinical Implications.

OBJECTIVE: The current definition of chronic migraine is relatively new. This definition has been field tested multiple times and has gone through multiple revisions. The evolution of the concept of migraine and its transformation to involve the category of chronic migraine is outlined. DISCUSSION: Chronic migraine as a disease was initially recognized in patients seen in headache clinics with a large burden of disability from frequent headaches and a history of prior migraines. Over time, this observation was operationalized into multiple diagnostic criteria with requirements for frequent headache days, typically 15 or more, and additionally a certain predisposition to migraine phenotype whether counted in number of headaches with migrainous features or a transformation from migraine in certain diagnostic criteria. In addition, the observation of medication overuse in this population raises a valid question - whether this is a factor for chronification versus a separate secondary headache etiology. CONCLUSION: Chronic migraine is a relatively newly recognized disease. We have an increasing number of medications studied specifically in chronic migraines, and these are briefly introduced. Additionally, there are guidelines to help design trials in chronic migraine. A valid future research question is to further study the efficacy of the medications studied in an undifferentiated migraine population, as there is economic pressure to use these medications as first line.

Multisensory integration in early vestibular processing in mice: the encoding of passive vs. active motion.

The mouse has become an important model system for studying the cellular basis of learning and coding of heading by the vestibular system. Here we recorded from single neurons in the vestibular nuclei to understand how vestibular pathways encode self-motion under natural conditions, during which proprioceptive and motor-related signals as well as vestibular inputs provide feedback about an animal's movement through the world. We recorded neuronal responses in alert behaving mice focusing on a group of neurons, termed vestibular-only cells, that are known to control posture and project to higher-order centers. We found that the majority (70%, n = 21/30) of neurons were bimodal, in that they responded robustly to passive stimulation of proprioceptors as well as passive stimulation of the vestibular system. Additionally, the linear summation of a given neuron's vestibular and neck sensitivities predicted well its responses when both stimuli were applied simultaneously. In contrast, neuronal responses were suppressed when the same motion was actively generated, with the one striking exception that the activity of bimodal neurons similarly and robustly encoded head on body position in all conditions. Our results show that proprioceptive and motor-related signals are combined with vestibular information at the first central stage of vestibular processing in mice. We suggest that these results have important implications for understanding the multisensory integration underlying accurate postural control and the neural representation of directional heading in the head direction cell network of mice.