The evolving electroclinical syndrome of “epilepsy with ring chromosome 20”

Radhakrishnan, Ashalatha; Menon, Ramshekhar; Hariharan, S; Radhakrishnan, Kurupath

doi:10.1016/j.seizure.2011.09.009

Cited by 23 publications

(55 citation statements)

References 26 publications

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“…1,4 Cytogenetic analysis represents the gold standard of the definitive diagnosis, but it is often delayed as not routinely performed. Therefore, [r (20)] syndrome is undoubtedly an underdiagnosed condition and the real prevalence is not known. 5 The following distinctive electroclinical features have been described in the syndrome: (1) long-lasting, bilateral, paroxysmal high voltage slow waves with spikes over the frontal areas, which are frequently associated with NCSE; 1 (2) ictal bursts of diffuse, frontally predominant, fast activities associated with clinical signs typically reported in frontal lobe seizures; 2,6 (3) a peculiar subcontinuous electroencephalography (EEG) trait constituted by trains of theta-delta waves, with a peak frequency of 5 Hz (range between 3 and 7 Hz).…”

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confidence: 99%

“…5 The following distinctive electroclinical features have been described in the syndrome: (1) long-lasting, bilateral, paroxysmal high voltage slow waves with spikes over the frontal areas, which are frequently associated with NCSE; 1 (2) ictal bursts of diffuse, frontally predominant, fast activities associated with clinical signs typically reported in frontal lobe seizures; 2,6 (3) a peculiar subcontinuous electroencephalography (EEG) trait constituted by trains of theta-delta waves, with a peak frequency of 5 Hz (range between 3 and 7 Hz). 1,4 Overall, the electroclinical features of epilepsy in [r (20)] syndrome suggest the involvement of the frontal lobes networks in the generation of ictal and interictal activities. Moreover, because seizures are frequently drug resistant and characterized by prolonged NCSE, a functional impairment in subcortical structures that modulate cortical excitability has been proposed.…”

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confidence: 99%

“…Particularly, a dopaminergic dysfunction of basal ganglia networks has been reported by means of positron emission tomography (PET) and singlephoton emission computed tomography (SPECT). 7,8 We recently demonstrated in one [r (20)] syndrome patient the ictal involvement of the substantia nigra and striatum during brief seizures by means of an EEG-functional magnetic resonance imaging (fMRI) study. 9 However, the mechanisms underlying the seizure disorder and, more generally the EEG abnormalities in [r (20)] syndrome remain to be elucidated.…”

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confidence: 99%

“…To date, studies have been published in continuous spike-and-wave during sleep (CSWS), Lennox-Gastaut syndrome (LGS), and West (WS) syndromes, [11][12][13][14] revealing the existence of specific networks involved during the pathologic activity in such conditions. In [r (20)] syndrome, we recently showed that the typical theta-delta rhythm is generated within the frontoparietal cortices, suggesting a dysfunction of the premotor/sensorimotor systems. 15 In this work, we present the BOLD changes related to the EEG abnormalities as revealed by the EEG-fMRI coregistration.…”

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confidence: 99%

“…15 In this work, we present the BOLD changes related to the EEG abnormalities as revealed by the EEG-fMRI coregistration. In particular, we aim to identify the brain regions involved in the generation of the different EEG abnormalities in patients with [r (20)] syndrome. Moreover, we hypothesize the existence of a common brain network for the paroxysmal high voltage sharp waves, the fast ictal discharges, and the slow-wave 3-7 Hz rhythms that characterize this condition.…”

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Epilepsy‐related brain networks in ring chromosome 20 syndrome: An EEG‐fMRI study

et al. 2014

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SUMMARYObjective: To identify the brain networks that are involved in the different electroencephalography (EEG) abnormalities in patients with ring chromosome 20 [r(20)] syndrome. We hypothesize the existence of both distinctive and common brain circuits for the paroxysmal high voltage sharp waves (hSWs), the seizures, and the slow-wave 3-7 Hz rhythm that characterize this condition. Methods: Thirteen patients with [r(20)] syndrome were studied by means of EEG simultaneously recorded with functional magnetic resonance imaging (EEG-fMRI). EEG traces were reviewed in order to detect the pathologic interictal (hSWs) and ictal activities; the 3-7 Hz theta-delta power was derived using a fast Fourier transform. A group-level analysis was performed for each type of EEG abnormality separately using a fixed-effect model and a conjunction analysis. Finally, a second-level random-effect model was applied considering together the different EEG abnormalities, without distinction between hSW, seizures, or theta-delta rhythms. Results: Subcontinuous theta-delta rhythm was recorded in seven patients, seizures in two, and hSWs in three patients. The main results are the following: (1) the slow-wave rhythm was related to blood oxygen level-dependent (BOLD) increases in the premotor, sensory-motor, and temporoparietal cortex, and to BOLD decrements involving the default mode (DMN) and the dorsal attention networks (DANs); (2) the ictalrelated BOLD changes showed an early involvement of the prefrontal lobe; (3) increases in BOLD signal over the basal ganglia, either for interictal and ictal activities, were observed; (4) a common pattern of positive BOLD changes in the bilateral perisylvian regions was found across the different EEG abnormalities. Significance: The BOLD increment in the perisylvian network and the decrease of the DMN and DAN could be the expression of the [r(20)] syndrome-related cognitive and behavioral deficits. The observed BOLD patterns are similar to the ones detected in other epileptic encephalopathies, suggesting that different epileptic disorders characterized by neurobehavioral regression are associated with dysfunction in similar brain networks.

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Epilepsy‐related brain networks in ring chromosome 20 syndrome: An EEG‐fMRI study

et al. 2014

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Assessing the role of ketogenic dietary therapy in ring chromosome 20 syndrome: A patient‐led approach

Gordon¹,

Watson²,

Desurkar

et al. 2020

Epilepsia Open

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Ring chromosome 20 syndrome (r(20)) is an ultra-rare disease characterized by drug-refractory epilepsy, cognitive impairment, and behavioral problems.Nonpharmacological treatments alongside antiepileptic drugs early after diagnosis may help reduce seizure frequency and preserve cognition. Ketogenic dietary therapy (KDT) has benefitted children with complex, refractory epilepsies, but its efficacy in r(20) is unknown. We assessed clinical prescription, implementation, and patient experience of KDT in r(20) through online surveys and a workshop. Forty-two patients, families, carers, and 23 healthcare professionals completed the surveys. While nearly all patients were familiar with KDT, only half had tried it. Significant improvement in seizure activity, cognition, and alertness was reported; side effects were typically mild but with one report of increased seizure frequency. A high rate of co-morbidity, older age at presentation, behavioral problems, and cognitive impairment can make implementing KDT in r(20) challenging. In the UK, NHS KDT services are predominantly available to pediatric patients, with very limited adult access. A health economic analysis illustrating reduced acute care costs or improved quality of life may support more widespread KDT implementation. Growing evidence supports KDT as an effective and safe intervention, but further research is needed to understand the mechanisms of r(20) and its interaction with ketosis. K E Y W O R D Sco-production, KDT, ketogenic dietary therapy, refractory epilepsy, ring chromosome 20 syndrome r(20)

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