Neuronal Networks in West Syndrome as Revealed by Source Analysis and Renormalized Partial Directed Coherence

Japaridze, Natia; Muthuraman, Muthuraman; Moeller, Friederike; Boor, Rainer; Anwar, Abdul Rauf; Deuschl, Günther; Stephani, Urlich; Raethjen, Jan; Siniatchkin, Michael

doi:10.1007/s10548-012-0245-y

Cited by 52 publications

(53 citation statements)

References 107 publications

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“…Some groups have attempted to quantitatively describe the underlying functional and neuronal network that facilitates hypsarrhythmia through EEG-fMRI (Siniatchkin et al 2007), source analysis methods (Japaridze et al 2013), and detection of fast oscillations (Kobayashi et al 2015). Though the hypsarrhythmia signal is often empirically described as “chaotic,” with the term describing the signal’s disorganized appearance (Pavone et al 2013), the mathematical definition of chaos and signal nonlinearity has been explored in several forms of epilepsy (Babloyantz and Destexhe 1986; Van Putten and Stam 2001; Kannathal et al 2014).…”

Section: Discussionmentioning

confidence: 99%

Long-Range Temporal Correlations Reflect Treatment Response in the Electroencephalogram of Patients with Infantile Spasms

et al. 2017

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Infantile spasms syndrome is an epileptic encephalopathy in which prompt diagnosis and treatment initiation are critical to therapeutic response. Diagnosis of the disease heavily depends on the identification of characteristic electroencephalographic (EEG) patterns, including hypsarrhythmia. However, visual assessment of the presence and characteristics of hypsarrhythmia is challenging because multiple variants of the pattern exist, leading to poor inter-rater reliability. We investigated whether a quantitative measurement of the control of neural synchrony in the EEGs of infantile spasms patients could be used to reliably distinguish the presence of hypsarrhythmia and indicate successful treatment outcomes. We used autocorrelation and Detrended Fluctuation Analysis (DFA) to measure the strength of long-range temporal correlations in 21 infantile spasms patients before and after treatment and 21 control subjects. The strength of long-range temporal correlations was significantly lower in patients with hypsarrhythmia than control patients, indicating decreased control of neural synchrony. There was no difference between patients without hypsarrhythmia and control patients. Further, the presence of hypsarrhythmia could be classified based on the DFA exponent and intercept with 92% accuracy using a support vector machine. Successful treatment was marked by a larger increase in the DFA exponent compared to those in which spasms persisted. These results suggest that the strength of long-range temporal correlations is a marker of pathological cortical activity that correlates with treatment response. Combined with current clinical measures, this quantitative tool has the potential to aid objective identification of hypsarrhythmia and assessment of treatment efficacy to inform clinical decision-making.

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Section: Discussionmentioning

confidence: 99%

Long-Range Temporal Correlations Reflect Treatment Response in the Electroencephalogram of Patients with Infantile Spasms

et al. 2017

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“…The sources found in the thalamus corresponded with positive BOLD signal changes in the thalamus in all patients. Also other recent studies used fMRI results obtained in the same patients in order to validate results of DICS analysis and demonstrated a good correspondence between sources in deep brain structures and BOLD signal changes in the same brain areas [31,58]. Compared with other methods of source reconstruction, DICS has some advantages that increase its power in the detection of deep brain sources.…”

Section: Discussionmentioning

confidence: 96%

“…In this study, we use a regularization value of α = 0.001. This value is chosen due to the reason that it is tested in simulations and successfully applied in real data not yielding spurious spatial extension of sources for a voxel definition of 5 mm [30,31]. The brain region representing the strongest power in a specific frequency band can subsequently be used as a reference region for cortico-cortical coherence analysis.…”

Section: Methodsmentioning

confidence: 99%

Dynamic Imaging of Coherent Sources Reveals Different Network Connectivity Underlying the Generation and Perpetuation of Epileptic Seizures

et al. 2013

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The concept of focal epilepsies includes a seizure origin in brain regions with hyper synchronous activity (epileptogenic zone and seizure onset zone) and a complex epileptic network of different brain areas involved in the generation, propagation, and modulation of seizures. The purpose of this work was to study functional and effective connectivity between regions involved in networks of epileptic seizures. The beginning and middle part of focal seizures from ictal surface EEG data were analyzed using dynamic imaging of coherent sources (DICS), an inverse solution in the frequency domain which describes neuronal networks and coherences of oscillatory brain activities. The information flow (effective connectivity) between coherent sources was investigated using the renormalized partial directed coherence (RPDC) method. In 8/11 patients, the first and second source of epileptic activity as found by DICS were concordant with the operative resection site; these patients became seizure free after epilepsy surgery. In the remaining 3 patients, the results of DICS / RPDC calculations and the resection site were discordant; these patients had a poorer post-operative outcome. The first sources as found by DICS were located predominantly in cortical structures; subsequent sources included some subcortical structures: thalamus, Nucl. Subthalamicus and cerebellum. DICS seems to be a powerful tool to define the seizure onset zone and the epileptic networks involved. Seizure generation seems to be related to the propagation of epileptic activity from the primary source in the seizure onset zone, and maintenance of seizures is attributed to the perpetuation of epileptic activity between nodes in the epileptic network. Despite of these promising results, this proof of principle study needs further confirmation prior to the use of the described methods in the clinical praxis.

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“…Moreover, the activation pattern seems to be specific for West syndrome, as it was not observed in infants with focal epilepsies. It is interesting to note that the subsequent source analysis, which was performed in the same sample of subjects for high amplitude slow activity, revealed similar electrical sources in the occipital cortex, putamen, and brainstem as shown by fMRI and even hypothesized a functional hierarchy between the sources, where the activity in brainstem seems to play an important key role in the pathogenesis of West syndrome (Japaridze et al., ). These data suggest that the involvement of brainstem is necessary and explains both the clinical seizures that might result from intermittent interference of descending brainstem pathways controlling spinal reflex activity and resulting in bilateral abrupt seizures, and the characteristic EEG features of hypsarrhythmia, which might be related to the activity in the ascending pathways from the same brainstem areas that project widely to the cerebral cortex (Juhasz et al., ; Frost and Hrachovy,).…”

Section: West Syndromementioning

confidence: 92%

Functional neuroimaging in epileptic encephalopathies

Siniatchkin

Capovilla

2013

Epilepsia

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SUMMARYEpileptic encephalopathies (EEs) represent a group of severe epileptic disorders associated with cognitive and behavioral disturbances. The mechanisms of cognitive disability in EEs remain unclear. This review summarized neuroimaging studies that have tried to describe specific fingerprints of brain activation in EE. Although the epileptic activity can be generated individually in different brain regions, it seems likely that the activity propagates in a syndrome-specific way. In some EEs, the epileptiform discharges were associated with an interruption of activity in the default mode network. In another EE, other mechanisms seem to underlie cognitive disability associated with epileptic activity, for example, abnormal connectivity pattern or interfering activity in the thalamocortical network. Further neuroimaging studies are needed to investigate the short-term and long-term impact of epileptic activity on cognition and development.

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Neuronal Networks in West Syndrome as Revealed by Source Analysis and Renormalized Partial Directed Coherence

Cited by 52 publications

References 107 publications

Long-Range Temporal Correlations Reflect Treatment Response in the Electroencephalogram of Patients with Infantile Spasms

Long-Range Temporal Correlations Reflect Treatment Response in the Electroencephalogram of Patients with Infantile Spasms

Dynamic Imaging of Coherent Sources Reveals Different Network Connectivity Underlying the Generation and Perpetuation of Epileptic Seizures

Functional neuroimaging in epileptic encephalopathies

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