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Functional neuroimaging abnormalities in idiopathic generalized epilepsy.

McGill ML, Devinsky O, Wang X, Quinn BT, Pardoe H, Carlson C, Butler T, Kuzniecky R, Thesen T - Neuroimage Clin (2014)

Bottom Line: There were no differences in FA values on DTI in tracts connecting the thalamus and prefrontal cortex.Functional analysis revealed decreased fALFF in the prefrontal cortex (PFC) subregion of the thalamus in patients with IGE.We provide minimum detectable effect sizes for each measure used in the study.

View Article: PubMed Central - PubMed

Affiliation: Comprehensive Epilepsy Center, Department of Neurology, New York University School of Medicine, New York, NY 10016, USA.

ABSTRACT
Magnetic resonance imaging (MRI) techniques have been used to quantitatively assess focal and network abnormalities. Idiopathic generalized epilepsy (IGE) is characterized by bilateral synchronous spike-wave discharges on electroencephalography (EEG) but normal clinical MRI. Dysfunctions involving the neocortex, particularly the prefrontal cortex, and thalamus likely contribute to seizure activity. To identify possible morphometric and functional differences in the brains of IGE patients and normal controls, we employed measures of thalamic volumes, cortical thickness, gray-white blurring, fractional anisotropy (FA) measures from diffusion tensor imaging (DTI) and fractional amplitude of low frequency fluctuations (fALFF) in thalamic subregions from resting state functional MRI. Data from 27 patients with IGE and 27 age- and sex-matched controls showed similar thalamic volumes, cortical thickness and gray-white contrast. There were no differences in FA values on DTI in tracts connecting the thalamus and prefrontal cortex. Functional analysis revealed decreased fALFF in the prefrontal cortex (PFC) subregion of the thalamus in patients with IGE. We provide minimum detectable effect sizes for each measure used in the study. Our analysis indicates that fMRI-based methods are more sensitive than quantitative structural techniques for characterizing brain abnormalities in IGE.

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Related in: MedlinePlus

A. Thalamic subregions based on axonal projections to specific cortical regions are depicted. B. Average fALFF values in the 0.01–0.08 Hz bandpass in normal controls and patients with IGE are shown in this graph. In the prefrontal subregion patients with IGE showed reduced fALFF values compared to controls.
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f0005: A. Thalamic subregions based on axonal projections to specific cortical regions are depicted. B. Average fALFF values in the 0.01–0.08 Hz bandpass in normal controls and patients with IGE are shown in this graph. In the prefrontal subregion patients with IGE showed reduced fALFF values compared to controls.

Mentions: Fractional amplitudes of low frequency fluctuations in the 0.01–0.08 Hz range compared to the entire detectable signal range (0–0.25 Hz) were averaged over every voxel in each of the seven thalamic subregions and the entire thalamus in each subject. The subregion that is connected structurally to the prefrontal cortex (PFC subregion) showed significant reductions (p = 0.023) in the fALFF values in IGE patients compared to controls (Fig. 1). fALFF differences in other subregions and the entire thalamus failed to reach significance.


Functional neuroimaging abnormalities in idiopathic generalized epilepsy.

McGill ML, Devinsky O, Wang X, Quinn BT, Pardoe H, Carlson C, Butler T, Kuzniecky R, Thesen T - Neuroimage Clin (2014)

A. Thalamic subregions based on axonal projections to specific cortical regions are depicted. B. Average fALFF values in the 0.01–0.08 Hz bandpass in normal controls and patients with IGE are shown in this graph. In the prefrontal subregion patients with IGE showed reduced fALFF values compared to controls.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221627&req=5

f0005: A. Thalamic subregions based on axonal projections to specific cortical regions are depicted. B. Average fALFF values in the 0.01–0.08 Hz bandpass in normal controls and patients with IGE are shown in this graph. In the prefrontal subregion patients with IGE showed reduced fALFF values compared to controls.
Mentions: Fractional amplitudes of low frequency fluctuations in the 0.01–0.08 Hz range compared to the entire detectable signal range (0–0.25 Hz) were averaged over every voxel in each of the seven thalamic subregions and the entire thalamus in each subject. The subregion that is connected structurally to the prefrontal cortex (PFC subregion) showed significant reductions (p = 0.023) in the fALFF values in IGE patients compared to controls (Fig. 1). fALFF differences in other subregions and the entire thalamus failed to reach significance.

Bottom Line: There were no differences in FA values on DTI in tracts connecting the thalamus and prefrontal cortex.Functional analysis revealed decreased fALFF in the prefrontal cortex (PFC) subregion of the thalamus in patients with IGE.We provide minimum detectable effect sizes for each measure used in the study.

View Article: PubMed Central - PubMed

Affiliation: Comprehensive Epilepsy Center, Department of Neurology, New York University School of Medicine, New York, NY 10016, USA.

ABSTRACT
Magnetic resonance imaging (MRI) techniques have been used to quantitatively assess focal and network abnormalities. Idiopathic generalized epilepsy (IGE) is characterized by bilateral synchronous spike-wave discharges on electroencephalography (EEG) but normal clinical MRI. Dysfunctions involving the neocortex, particularly the prefrontal cortex, and thalamus likely contribute to seizure activity. To identify possible morphometric and functional differences in the brains of IGE patients and normal controls, we employed measures of thalamic volumes, cortical thickness, gray-white blurring, fractional anisotropy (FA) measures from diffusion tensor imaging (DTI) and fractional amplitude of low frequency fluctuations (fALFF) in thalamic subregions from resting state functional MRI. Data from 27 patients with IGE and 27 age- and sex-matched controls showed similar thalamic volumes, cortical thickness and gray-white contrast. There were no differences in FA values on DTI in tracts connecting the thalamus and prefrontal cortex. Functional analysis revealed decreased fALFF in the prefrontal cortex (PFC) subregion of the thalamus in patients with IGE. We provide minimum detectable effect sizes for each measure used in the study. Our analysis indicates that fMRI-based methods are more sensitive than quantitative structural techniques for characterizing brain abnormalities in IGE.

Show MeSH
Related in: MedlinePlus