Audiovestibular sensory processing in migraine

Migraine can be conceptualised as a disorder of sensory processing, manifest by such symptoms as headache (pain), phonophobia and photophobia. Current models of migraine pathophysiology incorporate a significant role for the brainstem. Vestibular migraine (VM) is a subtype of the disorder in which significant brainstem dysfunction has been documented. The condition is known to have a significant effect on mental health. This study was designed to investigate disturbances in audiovestibular brainstem function in vestibular migraine in a four part study: 1. Otoacoustic emission suppression by contralateral noise, a test of auditory efferent pathway function, was measured in a group of 33 VM patients and compared with 31 healthy controls. Regression analysis showed a higher rate of abnormality amongst the VM group (p=0.03). 2. Vestibular evoked myogenic potentials were recorded in a group of 30 VM patients and compared with 35 healthy controls. Recordings showed a higher rate of abnormal responses in the VM group than amongst controls (p=0.008). 3. The potential for vestibular stimuli to act as migraine triggers was investigated by observing the effect of vestibular testing or a control condition on 148 individuals. Vestibular stimulation was associated with a significant increase in the probability of developing a migraine attack over the following 24 hour period (p=0.01). 4. Psychological symptoms of depression and anxiety were assessed using questionnaires 39 patients with VM and compared with a control group of 44 patients with dizziness of other causes. Although the VM group had a significantly higher load of symptoms of depression and anxiety, regression modelling showed that this effect was largely accounted for by an excess of dizziness symptoms. In conclusion, this study documents a number of audiovestibular sensory processing abnormalities using a variety of techniques. Vestibular migraine has a significant effect on psychological wellbeing, largely via the associated balance symptoms