Computational modeling of high frequency oscillations recorded with clinical intracranial macroelectrodes.

High Frequency Oscillations (HFOs) are a potential biomarker of epileptogenic regions. They have been extensively investigated in terms of automatic detection, classification and feature extraction. However, the mechanisms governing the generation of HFOs as well as the observability conditions on clinical intracranial macroelectrodes remain elusive. In this paper, we propose a novel physiologically-relevant macroscopic model for accurate simulation of HFOs as invasively recorded in epileptic patients. This model accounts for both the temporal and spatial properties of the cortical patch at the origin of epileptiform activity. Indeed, neuronal populations are combined with a 3D geometrical representation to simulate an extended epileptic source. Then, by solving the forward problem, the contributions of neuronal population signals are projected onto intracerebral electrode contacts. The obtained signals are qualitatively and quantitatively compared to real HFOs, and a relationship is drawn between macroscopic model parameters such as synchronization and spatial extent on the one hand, and HFO features such as the wave and fast ripple (200-600 Hz) components, on the other hand.

Ellis-Van Creveld syndrome with syndrome X--a rare association from the Indian subcontinent.

Ellis-Van Creveld syndrome or chondroectodermal dysplasia is a form of short-limbed dwarfism that affects the skeleton and skin appendages. Disproportionate dwarfism, postaxial polydactyly, ectodermal dysplasia, a small chest, and a high frequency of congenital heart defects characterize this autosomal recessive syndrome. Metabolic consequences of chondroectodermal dysplasia have not been reported previously from India. We report a case of chondroectodermal dysplasia associated with metabolic disturbances qualifying a diagnosis of syndrome X. To our knowledge, this association has not been previously reported in the medical literature, and helps to unravel the metabolic association of this disorder.