BrainCool-Migraine Intranasal Cooling Trial

Mechanical techniques to alleviate migraine symptoms have been used for many years, cooling and compression being the most frequently applied. Cryotherapy is the most common non-pharmacological self-administered pain-relieving method currently used by migraine sufferers. The first manuscript documenting the application of ice mixtures was published by James Arnott in 1849. Simple techniques based on cryotherapy, using various methods of cold and ice application have been reported over the last three decades. Friedman described a device using hollow metal tubes cooled by circulating cold water, applied to the periapical area of the maxillary molars. Sprouse-Blum reported benefit from applying frozen icepacks targeting carotid arteries at the front of the neck in migraine treatment.

Several pathophysiological mechanisms of action have been proposed. These mechanisms include:

1. Neurovascular mechanism: Application of cold induces vasoconstriction with subsequent decreased downstream blood flow. This leads to inhibition of the release of inflammatory mediators which results in decreased vascular permeability and local oedema.

2. Pain gating by differential effect on nerve conduction: Cryotherapy induces analgesia by slowing nerve conduction velocity, with small myelinated fibers being affected first, followed by large myelinated fibers and the unmyelinated fibers being affected last. Via mechanism of the gate control of pain, affecting the small myelinated nociceptive pain afferents first, cryotherapy induces analgesia.

3. Metabolic mechanism: Cryotherapy decreases metabolic and enzymatic activity, due to reduced demand for adenosine triphosphate (ATP) and oxygen.

4. Transient Receptor Potential (TRP) channels: Recent studies suggest that TRP channels may have a role in headache and pain genesis due to their response to environmental stimuli such as temperature changes.

The nasal cavity provides a large diffuse surface area that is highly vascular. Cooling via the nasal cavity therefore offers the ability to cool across the thin cribriform plate via both direct conductive mechanisms that do not rely on spontaneous circulation as well as indirect haematogenous mechanisms. Numerous subarachnoid and pial arterial branches exposed to the cerebrospinal fluid (CSF) have diameters in the range of the vessels of the retia mirabilia of animals in which selective brain cooling has been clearly established experimentally. Vascular anatomy allows transfer of venous blood from the skin of the head as well as nasal and paranasal mucous membranes to the dura mater thereby providing an excellent basis for the convective process of intranasal evaporative cooling. The dura mater, with its high vascularization, may transmit temperature changes to the CSF compartment, which may influence the temperature of brain parenchyma directly or indirectly, via brain arteries.

We suppose that another effect of intranasal cooling may be local vasoconstriction and subsequent associated vasoconstriction of cerebral arteries due to the presence of the nebulized coolant in the nasal cavity.

Many sufferers use mechanical techniques to relieve the headache. Simple techniques that have been recommended and tried include cryotherapy. Applying an icepack to the painful area has been the most frequently mentioned method. Many studies demonstrating the effectiveness of a variety of non-pharmacological modalities have been reviewed over the years. Although definite proof of effectiveness through traditional scientific method has been lacking in most instances. There is a trial reported by Friedman, where intraoral cooling was applied. Significant migraine relief has been obtained from chilling confined to the area. Thirty-five symptomatic episodic migraine patients were enrolled in this study, comparing 40 minutes of bilateral intraoral chilling, 50 mg of oral sumatriptan, and 40 minutes of sham (tongue) chilling. Hollow metal tubes chilled by circulating ice water were held in the maxillary molar periapical areas by the patient. Pain and nausea were recorded at baseline and 1, 2, 4, and 24 hours after start of treatment, using a numeric symptom-relief scale. Significant mean headache relief was obtained by maxillary chilling and sumatriptan at all four time intervals, with poor relief obtained by placebo. Maxillary chilling was more effective than sumatriptan at all four time intervals. Significant nausea relief was obtained by maxillary chilling and sumatriptan at post treatment and 2 and 4 hours later. At 24 hours, some headache and nausea recurrence was noted with sumatriptan. The repeated-measures analysis of variance indicated that both treatments, drug (P = 0.024) and maxillary chilling (P = 0.001), reduced the headache, as compared with the control group. Tenderness in the premolar area suggests local inflammation associated with vasodilatation and oedema. Because chilling can resolve local oedema, authors raised the possibility that an intraoral inflammation may be a factor in migraine aetiology. Although it is a possibility the cooling effect might have caused indirect vasoconstriction of the dilated meningeal blood vessels.

In the COOLHEAD 1 trial, investigators found that the use of RhinoChill® intranasal cooling within a clinic environment for 15 patients provided a statistically significant reduction of pain and associated symptoms of migraine at 5 minutes and 10 minutes (during treatment), and at 1 hour and 2 hours following treatment (all p values <0.001) along with a significant effect on pain and symptoms at 24 hours (p <0.001). In total, 87% of patients enrolled into the trial received a treatment benefit following from a short term (<20minutes) period of intranasal cooling.

Enrollment into the trial was challenging as participants were required to present at the hospital clinic for treatment between the hours of 9am to 7pm Monday to Friday, which for some, was too difficult while undergoing a migraine headache, and for others, the centre was not open for treatment at the time of their migraines. For those that did come in for treatment, it was found to be burdensome to travel while a migraine was present.

The results of this trial demonstrate that the RhinoChill® intranasal cooling device is both safe and effective to treat migraine patients within the setting of a hospital clinic environment. In this planned BrainCool-Migraine trial, the treatment will be self-administered by the patient. To allow for a swifter enrollment of patients into the study, to evaluate this treatment methodology in an as close to real world environment as possible, and to minimize any burden or discomfort to the patient by traveling to the hospital clinic with an active migraine headache on the one hand and to achieve best possible control of the study on the other hand, the self-administration by the patient in this study will be allowed and required to be done at home, as opposed to the clinic or any other location. The proven treatment methods and procedures as examined and described in the COOLHEAD 1 in-clinic trial will be implemented throughout the BrainCool-Migraine trial treatment procedures so as to ensure the high quality and standards associated with the previous trial.

It is recognised that migraine treatments are prone to placebo effects, which is further enhanced by the use of a medical device in an in-hospital setting, therefore in this BrainCool-Migraine trial, the design will be that of a double blinded, randomised, two arm, placebo control multicentre clinical trial.

The hypothesis we propose is that the application of RhinoChill® nasal cavity cooling will provide effective relief of pain and symptoms associated with episodic migraine (with or without aura). The null hypothesis is that no significant difference in pain scores, headache response or symptom severity scores will be found between the active treatment and placebo groups.