Abstracts

Sturge-Weber syndrome is a neurocutaneous disorder presenting with vascular malformations of the skin, brain and eye that frequently results in seizures, hemiparesis, cognitive impairments and neurodegenerative changes, including brain calcification and atrophy. The objective of this study was to determine whether a typical pattern of quantitative EEG findings is present in Sturge-Weber syndrome and whether it correlates with the clinical severity of involvement. Nine subjects (7 males, ages 9 months - 24 years) with unilateral Sturge-Weber syndrome had 16-channel EEG recordings. For each recording, two second, artifact-free epochs (N = 30) underwent a fast Fourier transform with frequency resolution of 0.5 Hz. In each epoch, absolute power values from pairs of symmetrical bipolar channels were used to calculate laterality scores (LS), where LS = (Left [ndash]Right) / (Left + Right). The LS was calculated for delta (2.0-3.5 Hz), theta (4.0-7.5 Hz), alpha (8.0-12.5 Hz), and beta (13.0-32.0 Hz) bands, as well as for total power (2-32 Hz). A blinded investigator assigned clinical severity scores based on seizures, hemiparesis, visual field-cut, and cognitive impairments (scores ranged from 0 to 15; 0 = no abnormality and 15 = severe impairments in all domains). In addition, EEGs were assigned scores based on qualitative assessments of degree of asymmetry in frequency, amplitude, and background. Six subjects (67%) demonstrated significant decreases in absolute power on the affected side relative to the unaffected side and all six of these had clinical severity scores greater than four. All six had decreases in power in the delta and alpha frequency bands, four with additional decreases in theta and beta bands. Three subjects (33%) demonstrated either no significant changes or an increase in absolute power on the affected side. All three of these subjects received a clinical severity score less than or equal to four. Spearman[rsquo]s rho statistic for mean laterality score (total power) versus clinical score was significant with a value of -.941 (p [lt] 0.001). There was no correlation between the qualitative EEG asymmetry score and clinical scores (Spearman[apos]s rho statistic =.377, p=0.317). Band-specific asymmetries were also not consistently appreciated on clinical interpretation. The majority of subjects demonstrated a decrease in absolute power on the affected side, most consistently involving the delta and alpha frequency bands. In this limited series, quantitative EEG correlated well with neurologic severity in Sturge-Weber syndrome, whereas standard EEG did not. Quantitative EEG also provided an objective measure of EEG abnormality. Further research is needed to determine whether quantitative EEG is a useful tool for early diagnosis or as a marker of disease progression. (Supported by RO1NS40596-01A1 supplementary funds NINDS/ORD and Hunter[apos]s Dream for a Cure Foundation Research grant)