Voxel-Based Morphometric Comparison of Hippocampal and Extrahippocampal Abnormalities in Patients with Left and Right Hippocampal Atrophy

Keller, Simon S.; Mackay, Clare E.; Barrick, Thomas R.; Wieshmann, Udo; Howard, Matthew A.; Roberts, Neil

doi:10.1006/nimg.2001.1072

Cited by 168 publications

(130 citation statements)

References 38 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…(Bertram and Scott, 2000) found consistent neuronal loss in the medial dorsal thalamic region in a rat population with limbic epilepsy; interestingly, they did not find consistent neuronal loss in the hippocampus, amygdala, or entorhinal cortex. In addition, many of the other regions found are consistently reported in other studies, such as the cingulate gyrus (Keller et al, 2002;Keller and Roberts, 2008) and the sensorimotor cortex primarily in the postcentral gyrus (Labate et al, 2011). The result of this comparison is consistent with other studies, and points to typical gray matter atrophy within our patient population.…”

Section: Figsupporting

confidence: 92%

“…However, studies examining the gray matter volume and gray matter concentration (GMC) of structures outside of the epileptic focus have revealed gray-matter alterations in structures beyond the hippocampus (Bernasconi et al, 2003;Bonilha et al, 2004Bonilha et al, , 2010Jutila et al, 2001;Keller et al, 2002). It is still not clear if recurrent seizure activity is the cause of the observed gray matter structural changes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

et al. 2013

View full text Add to dashboard Cite

Temporal-lobe epilepsy (TLE) involves seizures that typically originate in the hippocampus. There is evidence that seizures involve anatomically and functionally connected brain networks within and beyond the temporal lobe. Many studies have explored the effect of TLE on gray matter and resting-state functional connectivity in the brain. However, the relationship between structural and functional changes has not been fully explored. The goal of this study was to investigate the relationship between gray matter concentration (GMC) and functional connectivity in TLE at the voxel level. A voxel-wise linear regression analysis was performed between GMC maps and whole-brain resting-state functional connectivity maps to both the left thalamus (Lthal) and the left hippocampus (LH) in a group of 15 patients with left TLE. Twenty regions were found that exhibited GMC decreases linearly correlated with resting-state functional connectivity to either the LH or the Lthal in the patient group only. A subset of these regions had significantly reduced GMC, and one of these regions also had reduced functional connectivity to the LH in TLE compared to the controls. These results suggest a network of impairment in left TLE where more severe reductions in GMC accompany decreases (LH, Lthal, right midcingulate gyrus, left precuneus, and left postcentral gyrus) or increases (LH to right thalamus) in resting functional connectivity. However, direct relationships between these imaging parameters and disease characteristics in these regions have yet to be established.

show abstract

Section: Figsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

et al. 2013

View full text Add to dashboard Cite

show abstract

“…As mentioned before, it is well‐known that patients with left MTLE have worse performance in memory tasks and distinct structural damage of cerebral gray and white matter than patients with right MTLE [Besson et al, 2014; Keller et al, 2002; Riederer et al, 2008]. These data put together implies that right and left MTLE could have different pathological mechanisms.…”

Section: Introductionmentioning

confidence: 82%

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Campos

Coan

Yasuda

et al. 2016

Human Brain Mapping

104

102

View full text Add to dashboard Cite

Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large‐scale RSNs is differently affected in patients with right‐ and left‐MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled in 70 regions of interest (ROIs), from resting‐state functional‐MRIs of 99 subjects (52 controls, 26 right‐ and 21 left‐MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF2C‐toolbox, which provided ROI‐wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right‐MTLE. Both groups showed abnormal correlation between the dorsal‐DMN and the posterior salience, as well as between the dorsal‐DMN and the executive‐control network. Patients with left‐MTLE also showed reduced correlation between the dorsal‐DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left‐MTLE expressed a low cluster coefficient, whereas the altered connections on right‐MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right‐ and left‐MTLE patients with HS have widespread abnormal interactions of large‐scale brain networks; however, all parameters evaluated indicate that left‐MTLE has a more intricate bihemispheric dysfunction compared to right‐MTLE. Hum Brain Mapp 37:3137–3152, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

show abstract

“…Findings of WM diffusion alterations have also been complemented by gray matter disruption. These studies have demonstrated bilateral extensive cortical gray matter volume loss in MTLE-HS [35] which is greater in patients with left sided disease [36]. The extant of gray matter disruption is closely related to the start of the disease [37] and also more severe in regions that are anatomically and functionally connected to the hippocampus [38,39].…”

Section: Discussionmentioning

confidence: 96%

Age at onset and seizure frequency affect white matter diffusion coefficient in patients with mesial temporal lobe epilepsy

Nagy

Horváth

Perlaki

et al. 2016

Epilepsy & Behavior

View full text Add to dashboard Cite

SummaryIn mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), structural abnormalities are present not only in the hippocampus, but also in the white matter with ipsilateral predominance. Although the timing of epilepsy onset is commonly associated with clinical and semiological dissimilarities, limited data exist regarding white matter diffusion changes with respect to age at epilepsy onset. The aim of this study was to investigate diffusion changes in the white matter of unilateral MTLE-HS patients with respect to clinical parameters and to compare them to an age-and sex matched healthy control group. Apparent diffusion coefficients (ADCs) were derived using mono-exponential approaches from 22 (11 early and 11 late age at onset) unilateral MTLE-HS patients and 22 age-and sex matched control subjects after acquiring diffusion-weighted images on a 3T MRI system. Data were analyzed using two-tailed t-tests and multiple linear regression models. In the early onset MTLE-HS group ADC was significantly elevated in the ipsilateral hemispheric (p=0.04) and temporal lobe white matter (p=0.01) compared to controls. These differences were not detectable in late onset MTLE-HS patients. ADC of the early onset MTLE-HS group was negatively related to age at epilepsy onset in the ipsilateral hemispheric white matter (p=0.03) and the uncinate fasciculus (p=0.03), while in late onset patients ADC was no longer dependent on age at epilepsy onset itself, but rather on the seizure frequency in the ipsilateral uncinate fasciculus (p=0.03). Such diffusivity pattern has been associated with chronic white matter degeneration, reflecting myelin loss and higher extracellular volume which are more pronounced in the fronto-temporal regions and also depends on clinical features. In the early onset group, the timing of epilepsy seems to be the major cause of white matter abnormalities while in late onset disease it has a secondary role in provoking diffusion changes.

show abstract

Voxel-Based Morphometric Comparison of Hippocampal and Extrahippocampal Abnormalities in Patients with Left and Right Hippocampal Atrophy

Cited by 168 publications

References 38 publications

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Age at onset and seizure frequency affect white matter diffusion coefficient in patients with mesial temporal lobe epilepsy

Contact Info

Product

Resources

About