The visual evoked potential in the assessment of central nervous system effects of pre-eclampsia: a pilot study

Visual evoked potentials in women with and without preeclampsia during pregnancy and postpartum

OBJECTIVE

Preeclampsia is a severe hypertensive disorder of pregnancy which may lead to brain complications such as eclampsia. Visual symptoms are present in ∼25% of preeclamptic women suggesting the visual cortex to be altered during preeclampsia. Visual evoked potentials (VEPs) measure the functional neuronal integrity of the visual pathway from retina to the occipital cortex of the brain. The objective of this study was to compare neurophysiological changes in women with preeclampsia and other hypertensive disorders of pregnancy, using VEPs. We hypothesized that women with preeclampsia and other hypertensive disorders of pregnancy develop abnormal latency and amplitude of VEPs as compared with normotensive pregnant women.

METHODS

We performed a prospective observational study in 15 women with mild preeclampsia, 33 with severe preeclampsia (sPE), eight women with chronic hypertension, nine with pregnancy-induced hypertension, and 29 normotensive pregnant women. VEP measurements were made at four different time points of gestation (12-14 weeks, 26-28 weeks, 32-34 weeks, 36-40 weeks) and 6-8 weeks postpartum.

RESULTS

We defined reference values for normotensive pregnant women. Normotensive pregnant women had a shorter latency during pregnancy compared to their postpartum value (P = 0.005). Women with sPE had a prolonged latency of VEPs compared with normotensive pregnant women (P = 0.006), a difference that disappeared postpartum.

CONCLUSION

Our study showed neurophysiological adaptation to pregnancy of the visual cortex in normotensive pregnant women, that seemed to be absent in women with sPE. The study groups of women with chronic hypertension and pregnancy-induced hypertension were to small to draw any conslusions from.

Specialized Diagnostic Investigations to Assess Ocular Status in Hypertensive Diseases of Pregnancy

This review describes specialized diagnostic investigations to assess ocular status in hypertensive diseases of pregnancy. Ocular assessment can aid in early detection for prompt multidisciplinary treatment, obstetric intervention and follow-up. The investigations accurately predict the possible causes of blindness in hypertensive diseases of pregnancy. The investigations include fluorescein angiography, ophthalmodynamometry, fluorophotometry, imaging modalities, OCT, ultrasonography, doppler velocimetry and blood chemistry analysis. The review includes a summary of imaging techniques and related recent developments to assess the neuro-ophthalmic aspects of the disease. The imaging modalities have been instrumental in understanding the complex neuropathophysiological mechanisms of eclamptic seizures. The importance of blood chemistry analysis in hypertensive diseases of pregnancy has been emphasized. The investigations have made a significant contribution in improving the standards of antenatal care and reducing maternal and fetal morbidity and mortality.