Vestibular migraine (VM) is a progressively understood disorder in which patients present with episodes of vertigo or unsteadiness that are accompanied by a history of migraine at or before the onset of the disease.
1. About the naming of VM
There are many names for the disease entity of migraine-induced vertigo, such as migraine-related vertigo, migraine-related dizziness, migraine-related vestibular dysfunction disorder, migrainous vertigo, benign positional vertigo, and basal migraine have all been used.
2 .Pathogenesis of VM
Currently, the pathophysiological mechanism of VM is not clear, and some scholars have proposed several hypotheses: cortical spreading inhibition is a hypothesis to explain migraine aura. The role of some neurotransmitters has been postulated. Hereditary, familial; vasospasm of the vagus artery is a possible mechanism for the pathogenesis of VM.
3 , Clinical features
3.1 Morbidity
The incidence of migraine is high in the general population, ranging from 4% to 6% in men, 11% to 17% in women, and even up to 20% in women aged 30-49. VM can occur at any age, with a male to female ratio of 1:1.5 to 5. In most patients, migraine appears before the diagnosis of VM. Benign episodic vertigo in childhood is likely to be an early manifestation of VM, with an incidence of about 2.8% in children aged 6 to 12 years. Menopausal females often present with vertigo only and do not exhibit headache conditions at the onset.
3.2 Clinical manifestations of VM
1) VM can be spontaneous or positional vertigo. 40% to 70% of patients have positional vertigo (vertigo that occurs when the head position is shifted to a specific position) during an attack, but most are able to walk on their own, and moving to a specific position can trigger or worsen vertigo.
2) Visual vertigo is another main characteristic of VM, which refers to vertigo induced by being in a moving and changing scene (commercial area, movie theater), or by strong light changes. It is accompanied by nausea and balance disorders.
3) The duration and frequency of attacks vary greatly. The duration of vertigo varies from a few seconds (about 10%) and minutes (30%) to several hours (30%) and days (30%). The frequency of vertigo attacks is very irregular, usually patients complain of attacks from once a month to once a year, and some women may have an attack of VM before each menstrual period.
4) The location and severity of the headache varies. Vertigo often occurs during migraine attacks, but can also occur during inter- or pre-migraine periods. Photophobia, phonophobia, fear of smell and visual or other aura are the most common concomitant symptoms of VM and these are extremely important for diagnosis. Usually perimenopausal women with VM present only with vertigo and no migraine symptoms.
5) Hearing loss and tinnitus are not the main symptoms in patients with VM, but they have been reported in some of the literature.
6) About 65% of VM patients present with psychiatric symptoms, compared to 22% of BPPV. In some patients, mental and emotional abnormalities can lead to dizziness.
4. Ancillary tests
There are no ancillary tests to confirm the diagnosis of VM, and the diagnosis mainly relies on medical history. MRI of the brain is mainly used to exclude infarction, hemorrhage, tumor and other disorders in the brain.
5.Diagnostic criteria
The diagnosis mainly depends on the medical history. Table 1 Diagnostic criteria of VM
Definite VM:
1, at least moderate to severe episodic vestibular symptoms (vestibular system symptoms are considered “moderate” if they affect but do not interfere with daily life; “severe” if the patient is unable to perform daily life).
2. Current or past history of migraine according to the 2004 ISH diagnostic criteria
3. The presence of one of the following migraine symptoms in 2 or more episodes of vertigo: migraine headache, photophobia, phonophobia, visual or other aura.
4. Exclusion of other etiologies
Possible VM
1. At least moderate episodic vestibular symptoms
2. With one of the following symptoms.
(1) Current migraine or past history according to the 2004 ISH diagnostic criteria
(2) Migrainous symptoms among vestibular symptoms
(3) More than half of the vertigo episodes as migraine triggers: food, irregular sleep, altered hormone levels in the body
(4) More than half of the vertigo attacks are effective for the treatment of migraine with drugs
(3) Relevant tests to exclude other diseases
6 . Prevention and control measures
Treatment, including avoidance of triggering factors, preventive treatment and treatment in the acute phase. In addition, physiotherapy and psychological treatment should be considered.
6.1 Medication
The goal of preventive medication is to reduce the number of attacks to less than half of the original number. Flunarizine is commonly used. Acute phase treatment of VM can be attempted with tritans and vestibular depressants (e.g., promethazine, teicoplanin, and chlorpheniramine).
6.2 Non-pharmacological treatment
Avoiding known definite triggers, regular sleep and diet, and regular exercise may significantly improve the symptoms of VM.
In conclusion, VM is gradually being recognized as a disease. Epidemiological studies support the association of episodic vertigo with migraine and suggest that this condition is common. The diversity of clinical features and the lack of uniform diagnostic criteria have hindered the development of rational research and trials such as efficacy observations.