A critical view on the role of migraine triggers in the genesis of migraine pain

Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomised, double-blind, parallel-group, sham-controlled trial

BACKGROUND

Preliminary work suggests that single-pulse transcranial magnetic stimulation (sTMS) could be effective as a treatment for migraine. We aimed to assess the efficacy and safety of a new portable sTMS device for acute treatment of migraine with aura.

METHODS

We undertook a randomised, double-blind, parallel-group, two-phase, sham-controlled study at 18 centres in the USA. 267 adults aged 18-68 years were enrolled into phase one. All individuals had to meet international criteria for migraine with aura, with visual aura preceding at least 30% of migraines followed by moderate or severe headache in more than 90% of those attacks. 66 patients dropped out during phase one. In phase two, 201 individuals were randomly allocated by computer to either sham stimulation (n=99) or sTMS (n=102). We instructed participants to treat up to three attacks over 3 months while experiencing aura. The primary outcome was pain-free response 2 h after the first attack, and co-primary outcomes were non-inferiority at 2 h for nausea, photophobia, and phonophobia. Analyses were modified intention to treat and per protocol. This trial is registered with ClinicalTrials.gov, number NCT00449540.

FINDINGS

37 patients did not treat a migraine attack and were excluded from outcome analyses. 164 patients treated at least one attack with sTMS (n=82) or sham stimulation (n=82; modified intention-to-treat analysis set). Pain-free response rates after 2 h were significantly higher with sTMS (32/82 [39%]) than with sham stimulation (18/82 [22%]), for a therapeutic gain of 17% (95% CI 3-31%; p=0.0179). Sustained pain-free response rates significantly favoured sTMS at 24 h and 48 h post-treatment. Non-inferiority was shown for nausea, photophobia, and phonophobia. No device-related serious adverse events were recorded, and incidence and severity of adverse events were similar between sTMS and sham groups.

INTERPRETATION

Early treatment of migraine with aura by sTMS resulted in increased freedom from pain at 2 h compared with sham stimulation, and absence of pain was sustained 24 h and 48 h after treatment. sTMS could be a promising acute treatment for some patients with migraine with aura.

FUNDING

Neuralieve.

CaV2.1 channelopathies

Mutations in the CACNA1A gene that encodes the pore-forming alpha1 subunit of human voltage-gated CaV2.1 (P/Q-type) Ca2+ channels cause several autosomal-dominant neurologic disorders, including familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2, and spinocerebellar ataxia type 6 (SCA6). For each channelopathy, the review describes the disease phenotype as well as the functional consequences of the disease-causing mutations on recombinant human CaV2.1 channels and, in the case of FHM1 and SCA6, on neuronal CaV2.1 channels expressed at the endogenous physiological level in knockin mouse models. The effects of FHM1 mutations on cortical spreading depression, the phenomenon underlying migraine aura, and on cortical excitatory and inhibitory synaptic transmission in FHM1 knockin mice are also described, and their implications for the disease mechanism discussed. Moreover, the review describes different ataxic spontaneous cacna1a mouse mutants and the important insights into the cerebellar mechanisms underlying motor dysfunction caused by mutant CaV2.1 channels that were obtained from their functional characterization.