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Microstate alterations are present in patients with TLE. This feature might be useful in the diagnosis of epilepsy even in the absence of an IED.

Background and Purpose: Repetitive transcranial magnetic stimulation (rTMS) induces widespread changes in brain connectivity. As the network topology differences induced by a single session of rTMS are less known we undertook this study to ascertain whether the network alterations had a small-world morphology using multi-modal graph theory analysis of simultaneous EEG-fMRI.Method: Simultaneous EEG-fMRI was acquired in duplicate before (R1) and after (R2) a single session of rTMS in 14 patients with Writer’s Cramp (WC). Whole brain neuronal and hemodynamic network connectivity were explored using the graph theory measures and clustering coefficient, path length and small-world index were calculated for EEG and resting state fMRI (rsfMRI). Multi-modal graph theory analysis was used to evaluate the correlation of EEG and fMRI clustering coefficients.Result: A single session of rTMS was found to increase the clustering coefficient and small-worldness significantly in both EEG and fMRI (p < 0.05). Multi-modal graph theory analysis revealed significant modulations in the fronto-parietal regions immediately after rTMS. The rsfMRI revealed additional modulations in several deep brain regions including cerebellum, insula and medial frontal lobe.Conclusion: Multi-modal graph theory analysis of simultaneous EEG-fMRI can supplement motor physiology methods in understanding the neurobiology of rTMS in vivo. Coinciding evidence from EEG and rsfMRI reports small-world morphology for the acute phase network hyper-connectivity indicating changes ensuing low-frequency rTMS is probably not “noise”.

Background:The occurrence of impulse control disorders (ICDs) in Parkinson's disease (PD) is frequently attributed to dopamine replacement therapy. However, not all patients who receive medication develop ICDs. Recent imaging studies have suggested specific neuroanatomical abnormalities in patients with PD and ICD.Objectives:This study aims to identify changes in volumes of subcortical structures and cortical thickness specific to patients with PD and ICDs.Methodology:A total of 11 patients with PD and ICD (PDICD(+)), 15 patients with PD without ICD (PDICD(−)), and 15 healthy controls were analyzed in this study. ICDs were diagnosed and quantified using the Questionnaire for Impulsive-Compulsive Disorders in PD-Rating Scale (QUIP-RS). Structural imaging was performed on a 3T scanner; volumes of subcortical structures and cortical thickness were obtained using first in FSL and FreeSurfer.Results:Significant volume loss of the nucleus accumbens was observed in the PDICD(+) group. Several areas of significant cortical thinning were observed in the PDICD(+) group in comparison PDICD(−) group. Thinning of the left middle temporal gyrus, transverse temporal gyrus, and bilateral temporal poles was observed in the PDICD(+) group. No correlations were observed between QUIP-RS scores and areas of cortical thinning.Conclusions:The PDICD(+) group has specific neuroanatomical variations in the nucleus accumbens and temporal lobes, which may contribute to the development of ICD and perhaps predispose a patient to ICDs on exposure to dopamine replacement therapy.

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