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Objective Altered sensory processing is common in intellectual disability (ID). Here, we study electroencephalographic responses to auditory stimulation in human subjects presenting a rare condition (mutations in SYNGAP1) which causes ID, epilepsy and autism. Methods Auditory evoked potentials, time-frequency and inter-trial coherence analyses were used to compare subjects with SYNGAP1 mutations with Down syndrome (DS) and neurotypical (NT) participants (N = 61 ranging from three to 19 years of age). Results Altered synchronization in the brain responses to sound were found in both ID groups. The SYNGAP1 mutations group showed less phase-locking in early time windows and lower frequency bands compared to NT, and in later time windows compared to NT and DS. Time-frequency analysis showed more power in beta-gamma in the SYNGAP1 group compared to NT participants. Conclusions This study indicated reduced synchronization as well as more high frequencies power in SYNGAP1 mutations, while maintained synchronization was found in the DS group. These results might reflect dysfunctional sensory information processing caused by excitation/inhibition imbalance, or an imperfect compensatory mechanism in SYNGAP1 mutations individuals. Significance Our study is the first to reveal brain response abnormalities in auditory sensory processing in SYNGAP1 mutations individuals, that are distinct from DS, another ID condition.

Infantile spasms (IS) is a catastrophic epilepsy where treatment precocity improves outcome. Previous studies demonstrated an association between asymmetric hypsarrhythmia on EEG and ipsilateral hemispheric lesions on MRI, suggesting a possible role of cortical lesions in the initiation of IS. Epileptiform abnormalities appearing during early infancy have also been linked to IS emergence. We hypothesized that focal lateralized EEG abnormalities during the prehyspasrrhythmic period will be associated with asymmetric hypsarrhythmia at IS onset. We recruited a retrospective cohort of 80 infants, 7.4 ± 3.6 months old at the onset of hypsarrhythmia and IS, admitted to Sainte-Justine Hospital between 2007 and 2016. Seven infants showed an asymmetric hypsarrhythmia pattern and, as expected, all of them had lateralized lesions on MRI. Of the remaining 73, 42 had abnormal MRI, but only 3 infants had lateralized lesions (100% vs 7.1%, p Six had focal lateralized, while 23 multifocal abnormalities. The proportion of patients with focal abnormalities was higher in those who developed asymmetric compared to symmetric hypsarrhythmia (50% vs 13.3%, p Our data confirm the link between asymmetric hypsarrhythmia and lateralized MRI lesions. Moreover, we show that focal lateralized EEG abnormalities precede asymmetric hypsarrythmia, which supports the involvement of cerebral cortex in the IS genesis. More sensitive EEG biomarkers of high IS risk may help developing preventative treatments that will improve outcomes in IS.

Seizures are common and worsen the outcome in critically ill neonates. Predicting seizure recurrence could allow individualizing antiepileptic treatment and improving the outcome. To identify EEG signatures of seizure recurrence, we investigated periictal spectral power and electrographic characteristics of seizures in five consecutive asphyxiated neonates under continuous EEG monitoring. All patients had high seizure burden while undergoing hypothermic neuroprotection. Two neonates had recurrence of seizures on rewarming. Spectral power analysis of fifteen artifact-free consecutive ictal events demonstrated, in all neonates, a significant increase in overall spectral power from the interictal to preictal and ictal periods ( p

Background Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome that can present with many disabling neurological disorders, the most common being epilepsy. Although it is a chronic multi-system disease, healthcare utilization and long-term outcome of subjects with TSC are not yet well defined. The goal of this study was to evaluate the direct cost and long-term outcome of TSC in the province of Quebec, compared to other forms of epilepsy and healthy controls. Methods Our provincial health care database was interrogated to determine use of medical services by patients with TSC, epilepsy and healthy controls from 1996 to 2011. Data on demographics, outcomes and health care utilization were analyzed. Results 1004 TSC, 41,934 with epilepsy and 41,934 controls were identified. The prevalence of TSC was 1/7872 compared to 1/189 for epilepsy. TSC experienced more hospitalizations, medical visits and prescription drug use. Their most common admission diagnosis was seizures and age at death was significantly lower: 61.3 years old for TSC vs 69.6 and 76.6 years old for epilepsy and controls ( p 0.001 ). Conclusions TSC subjects have a significantly higher burden of disease than other subjects with epilepsy. These results stress the need for specialized services in this population through the lifespan.