ANTIEPILEPTIC DRUG EFFECT OF ON BRAIN CORTICAL NETWORKS IN PATIENTS WITH UNVERRICHT-LUNDBORG DISEASE

Authors: Chang-Chia Liu, Petros Xanthopoulos, Panos Pardalos, J. Zhang and B. Uthman

Content:
RATIONALE:
Efficacy of antiepileptic drug (AED) therapy in patients with Unverricht-Lundborg Disease (ULD) may be measured by changes in the Unified Myoclonus Rating Scale (UMRS) scores before and after treatment. While patients may experience clinically meaningful improvements, the UMRS may fail to detect a significant difference. Furthermore, the UMRS is a skewed scale and may not reflect the severity of the disease accurately, especially during the later stage of the disease.
METHODS:
In this study, mutual information and nonlinear interdependence measures were applied to electroencephalogram (EEG) recordings in an attempt to identify the effect of AED treatment on the coupling strength and directionality of information transport between different brain cortical regions. Four ULD subjects were included and two 1-hour EEG recordings were acquired for each; one shortly before and one after adding a new AED for a minimum of two months. All four subjects were siblings from the same parents and were close in age (48 ± 3 years) and duration of disease (~37.75 years).
RESULTS:
Lower mutual information between different brain cortical regions were seen in less severe patients (P1<P4<P2<P3). Adjunctive AED treatment was associated with significant decrease in the coupling strength and amount of information transport between different brain cortical regions in all four patients. The patient with least severity had the largest decrease in mutual information and information transport after treatment. The UMRS scores did not reflect the severity of the disease in cases of highest severity; perhaps due to limitation of the scale at later stages of the disease.
CONCLUSIONS:
The coupling strength and directionality of information transport between different brain cortical regions may provide a new insight for developing a novel surrogate outcome measure for patients with epilepsy when clinical observations could potentially fail to detect a significant difference. (Supported by: North Florida Foundation for Research and Education, Inc. National science Foundation, Air Force)