Abstracts

Ten to twenty percent of children with facial port-wine stain (PWS) develop neurologic features characteristic of Sturge-Weber syndrome (SWS), which may include seizures, visual field defects, hemiparesis, and cognitive impairment. Screening often involves serial neuroimaging, which carries a sedation risk and is often falsely negative in infants. We have reported that decreased power on the affected side correlated with neurologic impairments in subjects with SWS, and efforts are ongoing to develop quantitative EEG (qEEG) as a tool for early diagnosis in SWS. Three infants with unilateral facial port-wine stains had standard 16-channel EEG recordings at approximately 4 month intervals. Thirty artifact-free, two-second epochs were selected from each record. Bipolar data from each epoch was submitted to a fast Fourier transform with a frequency resolution of 0.5 Hz. Power spectra from each side of the head were compared using a laterality score (LS = (Left - Right) / (Left + Right). The LS were calculated for delta (2.0-3.5 Hz), theta (4.0-7.5 Hz), alpha (8.0-12.5 Hz), beta (13.0-32.0 Hz), and total power (2-32 Hz). All EEGs were independently read by an experienced electroencephalographer. Subject #1 had a left-sided PWS and initially left-sided brain involvement with his first focal seizure at 8 months of age. EEGs at 11 and 15 months were read as symmetric, but quantitative EEG showed significantly lower power in the left hemisphere. MRI at this time showed left-sided leptomeningeal angiomatosis. MRI at 18 months showed bilateral occipital lesions. Further EEGs at 19 and 23 months yielded no statistically significant asymmetries in total power, possibly reflecting either his bilateral involvement or normal development and fully controlled seizures. Subject #2 had EEGs at 2, 6, and 10 months of age that were read as normal; however, qEEG showed significantly lower ipsilateral power at 2 and 10 months. MRI at 6 months showed unilateral leptomeningeal enhancement. This child has never seized and is developmentally normal. Subject #3 had a single EEG at 4 months that was read as normal; qEEG showed no significant asymmetry. MRI at six months showed no stigmata of SWS. This infant has had neither seizures nor any neurodevelopmental delay. Subjects #2 and #3 will continue to have EEGs every 3 months for a total of two years. In infants with a unilateral port-wine stain, serial qEEG shows decreases in power over the hemisphere that is affected or at-risk for neurological impairment. Further studies are needed to determine if qEEG is a reliable and sensitive method for identifying children with unilateral PWS who need neuroimaging and determining the optimal timing of imaging.