Background: Disorders of the visual function in migraineurs have been recognized by neurophysi ol ogi cal
methods for many years. However, studies of the cortical visual evoked potentials have yielded contradictory
results. Changes in the retrobulbar hemodynamic in migraineurs with visual auras, have not been researched
extensively.
Objective: The aim of the present work is to study the visual evoked potentials as well as the blood flow
velocity, pulsatility index (PI) and resistance index (RI) in the ophthalmic and central retinal arteries in
migraine patients with and without aura.
Material & methods: The present study included thirty fife migraine patients and fifteen healthy control
subjects. Twenty patients have exclusively migraine with visual aura (MA), and fifteen without aura (MO).
The study was carried out during the headache-free periods, and all the patients and control groups were
subjected to : complete general examination, through neurological and full ophthalmic examination, patternshift
visual evoked potential (PS-VEP) assessment, and color doppler sonography of the ophthalmic (OA)
and central retinal (CRA) arteries.
Results: PS-VEP assessment showed prolongation of the N75, P100, and NI45 latencies of the MA
group, than in the MO and control groups, but significant difference was found only between the N75
and NI 45 latencies of the MA and control groups (P= 0.032, 0.039 respectively). The mean P100-N145
amplitude of the MO group was significantly higher than that of the control group (P=0.021). The mean
P I 00-N145 amplitude of the MA group was lower than that of the MO group but still higher than the control
group although none of the difference reached significant level. The mean PI of OA and CRA ,mean RI of
CRA, and mean end diastolic velocity of the CRA were significantly higher in MA group than in the control
subjects. Migraineurs without aura (MO), when compared to the controls, they showed the same trend as
the MA group, but none of the differences was statistically significant.
Conclusion: The present study gives support the role of cerebrovascular factors and ischemic damage in
the prolongation of the VEP wave latencies and decreased P100 amplitude in migraine patients with visual
aura. It also showed evidence of dysfunction in the retrobulbar circulation and hemodynamic changes that
may explain some of the visual symptoms reported by most migraineurs. |
