Functional seizures and their mimics: a retrospective service review of cases from a tertiary video telemetry database.

Objective: Identify the proportion of patients referred with putative functional seizures (FS) that were subsequently re-diagnosed as epileptic seizures (ES), or an alternative diagnosis, following video telemetry EEG (VTEEG). In addition, describe the characteristics of those seizures. Methods: The VTEEG reports from patients admitted to the Chalfont Centre for Epilepsy between 2019 and 2022 were reviewed. Pre-VTEEG and post-VTEEG diagnoses were compared to identify whether a diagnostic revision was made from suspected FS to ES or another diagnosis. Diagnostic revision cases were then grouped into cohorts with associated features and reviewed to characterise and describe FS mimics. Results: 444 VTEEG reports where patients had habitual events were identified. 4.7% of patients were referred with FS and were subsequently diagnosed with ES or another diagnosis. In this group, several cohorts could be identified including frontal lobe epileptic seizures, ES with functional overlay, insular or temporal lobe epileptic seizures associated with autonomic or marked experiential peri-ictal symptoms, and individuals who had both ES and FS but whose ES were revealed on medication withdrawal. Conclusion: In patients referred to a tertiary epilepsy unit, a small minority of cases had seizures diagnosed as functional and reclassified as epileptic or an alternative diagnosis. It is clinically important to be aware of these FS mimics.

Alternating hemiplegia of childhood: An electroclinical study of sleep and hemiplegia.

OBJECTIVE: Alternating Hemiplegia of Childhood (AHC) is characterised by paroxysmal hemiplegic episodes and seizures. Remission of hemiplegia upon sleep is a clinical diagnostic feature of AHC. We investigated whether: 1) Hemiplegic events are associated with spectral EEG changes 2) Sleep in AHC is associated with clinical or EEG spectral features that may explain its restorative effect. METHODS: We retrospectively performed EEG spectral analysis in five adults with AHC and twelve age-/gender-matched epilepsy controls. Five-minute epochs of hemiplegic episodes and ten-minute epochs of four sleep stages were selected from video-EEGs. Arousals were counted per hour of sleep. RESULTS: We found 1) hemispheric differences in pre-ictal and ictal spectral power (p = 0.034), during AHC hemiplegic episodes 2) 22% reduced beta power (p = 0.017) and 26% increased delta power (p = 0.025) during wakefulness in AHC versus controls. There were 98% more arousals in the AHC group versus controls (p = 0.0003). CONCLUSIONS: There are hemispheric differences in spectral power preceding hemiplegic episodes in adults with AHC, and sleep is disrupted. SIGNIFICANCE: Spectral EEG changes may be a potential predictive tool for AHC hemiplegic episodes. Significantly disrupted sleep is a feature of AHC.

The long-term course of temporal lobe epilepsy: From unilateral to bilateral interictal epileptiform discharges in repeated video-EEG monitorings.

INTRODUCTION: Bilateral interictal epileptiform discharges (IED) and ictal patterns are common in temporal lobe epilepsy (TLE) and have been associated with decreased chances of seizure freedom after epilepsy surgery. It is unclear whether secondary epileptogenesis, although demonstrated in experimental models, exists in humans and may account for progression of epilepsy. MATERIAL AND METHODS: We reviewed consecutive video-EEG recordings from 1992 to 2014 repeated at least two years apart (mean interval 6.14years) in 100 people diagnosed with TLE. RESULTS: Ictal EEG patterns and IED remained restricted to one hemisphere in 36 people (group 1), 46 exhibited bilateral abnormalities from the first recording (group 2), 18 progressed from unilateral to bilateral EEG pathology over time (group 3). No significant differences between the three groups were seen with respect to age at epilepsy onset, duration, or underlying pathology. Extra-temporal IED during the first EEG recording were associated with an increased risk of developing bilateral epileptiform changes over time (hazard ratio 3.67; 95% CI 1.4, 9.4). CONCLUSION: Our findings provide some support of progression in TLE and raise the possibility of secondary epileptogenesis in humans. The development of an independent contra-lateral epileptogenic focus is known to be associated with a less favorable surgical outcome. We defined reliable EEG markers for an increased risk of progression to more widespread or independent bitemporal epileptogenicity at an early stage, thus allowing for individualized pre-surgical counselling.

Ring Chromosome 17 Not Involving the Miller-Dieker Region: A Case with Drug-Resistant Epilepsy.

Chromosomal abnormalities are often identified in people with neurodevelopmental disorders including intellectual disability, autism, and epilepsy. Ring chromosomes, which usually involve gene copy number loss, are formed by fusion of subtelomeric or telomeric chromosomal regions. Some ring chromosomes, including ring 14, 17, and 20, are strongly associated with seizure disorders. We report an individual with a ring chromosome 17, r(17)(p13.3q25.3), with a terminal 17q25.3 deletion and no short arm copy number loss, and with a phenotype characterized by intellectual disability and drug-resistant epilepsy, including a propensity for nonconvulsive status epilepticus.

Drop attacks, falls and atonic seizures in the Video-EEG monitoring unit.

PURPOSE: We set out to determine clinical and EEG features of seizures presenting with falls, epileptic drop attacks and atonia in the video EEG monitoring unit. METHODS: We searched the video EEG monitoring reports over a 5-year-period for the terms "drop", "fall" and "atonic". RESULTS: Seizures presenting as epileptic drop attacks, falls or atonia were found in 23/1112 (2%) admissions. About half of the patients suffering from these seizure types had developmental delay and learning difficulties and in half of the patients a lesion was seen on MRI which was often frontal. The presumed epileptogenic zone was frontal in many cases (43%), unclear with regards to a region or multifocal in 48% and posterior temporal/occipital in 2 patients (9%). EEG patterns recorded were paroxysmal fast activity, spike and wave discharges and EEG attenuation. Seizure related falls were seen in 8 cases (34%) with injuries recorded during Video EEG monitoring in half of those. CONCLUSION: Clinical and EEG features outlined here can help the clinician to recognise patients at risk for these devastating seizure types.

The prognostic value of long-term ambulatory electroencephalography in antiepileptic drug reduction in adults with learning disability and epilepsy in long-term remission.

We determined the additional yield of ambulatory over routine electroencephalography recordings in predicting seizure recurrence after antiepileptic drug (AED) withdrawal in 15 adult patients with various epilepsy syndromes who had been seizure free for at least 3 years (median=10 years). Eleven of 15 patients (74%) relapsed during or after AED withdrawal. All six patients with epileptiform discharges on ambulatory electroencephalography prior to AED withdrawal relapsed, compared with five of nine patients without epileptiform discharges. Ambulatory electroencephalography significantly increases the yield in detecting epileptiform discharges (n=6) compared with routine electroencephalography (n=1). A negative electroencephalographic finding is only a poor predictor of seizure freedom following AED withdrawal. On clinical grounds, our data suggest that patients with epilepsy, learning disability, and other known risk factors (history of abnormal EEGs and frequent seizures, abnormal MRI) are at great risk of seizure relapse during AED taper, irrespective of very long periods of seizure freedom.

Partial epilepsy with pericentral spikes: a new familial epilepsy syndrome with evidence for linkage to chromosome 4p15.

The genetic analysis of simple Mendelian epilepsies remains a key strategy in advancing our understanding of epilepsy. In this article, we describe a new family epilepsy syndrome, partial epilepsy with pericentral spikes, which we map to chromosome 4p15. We distinguish it clinically, electrophysiologically, and genetically from previously described Mendelian epilepsies. The family described is a large Brazilian kindred of Portuguese extraction in which affected family members manifest a variety of seizure types, including hemiclonic, hemitonic, generalized tonic-clonic, simple partial (stereotyped episodes of epigastric pain), and complex partial seizures consistent with temporal lobe epilepsy. The syndrome is benign, either requiring no treatment or responding to a single antiepileptic medication. Seizure onset is in the first or second decades of life, with seizures in individuals up to the age of 71 years and documented encephalogram changes up to the age of 30 years. A key feature of partial epilepsy with pericentral spikes is a characteristic encephalogram abnormality of spikes or sharp waves in the pericentral region (centroparietal, centrofrontal, or centrotemporal). This distinctive encephalogram abnormality of pericentral spikes unites these several seizure types into a discrete family epilepsy syndrome. As with other familial epilepsies, the inherited nature of this new syndrome may be overlooked because of the variability in penetrance and seizure types among affected family members.