The problem of the evaluation of brain connectivity has become a fundamental one in the neurosciences during the latest years, as a way to understand the organization and the interaction of several cortical areas during the execution of cognitive or motor tasks. Following an approach that derives from the graph theory, we analyzed the architectural properties of the networks obtained by the use of DTF measures on the cortical signals estimated from the high resolution EEG recordings. The present work aims at analyse the structure of cortical connectivity during the imagination of a limb movement in spinal cord injured patients, by the computation of the characteristic path length L and the cluster indices Cin and Cout.