Postural instability during attacks of migraine without aura.

Abstract

Migraine has long been associated with unsteadiness and dizziness but postural control has not been studied in the ictal state. Here, the stability of upright stance during migraine attacks was measured. Static balance was assessed prospectively in migraine patients (n=30) during quiet stance for 40s on a posturographic force platform. Recordings were performed both ictally and in the pain-free interval. Subjects were assessed under four different conditions yielding different visual and proprioceptive feedback environments. Both ictal and interictal data were compared with age-matched healthy controls (n=30). Postural instability increased significantly under all experimental conditions during migraine attacks. Whilst standing on a foam pad with eyes closed, median sway area was 353mm2 in control subjects, 318mm2 in migraineurs in the pain-free period and 618mm2 in the ictal state. However, Romberg and vestibular Romberg quotients were not altered during migraine attacks. Spectral analyses of postural sway also showed similar profiles in migraineurs and controls. The severity of headache was inversely correlated to Romberg quotients. The demonstrated pattern of balance disorder during migraine attacks suggests a transient cerebellar dysfunction. Our findings also indicate that intense headache induces a re-weighting of sensory processing toward less dependence on visual and proprioceptive information.