Spatiotemporal patterns of electrocorticographic very fast oscillations (> 80 Hz) consistent with a network model based on electrical coupling between principal neurons.

PURPOSE: We sought to characterize spatial and temporal patterns of electrocorticography (ECoG) very fast oscillations (> ∼80 Hz, VFOs) prior to seizures in human frontotemporal neocortex, and to develop a testable network model of these patterns. METHODS: ECoG data were recorded with subdural grids from two preoperative patients with seizures of frontal lobe onset in an epilepsy monitoring unit. VFOs were recorded from rat neocortical slices. A "cellular automaton" model of network oscillations was developed, extending ideas of Traub et al. (Neuroscience, 92, 1999, 407) and Lewis & Rinzel (Network: Comput Neural Syst, 11, 2000, 299); this model is based on postulated electrical coupling between pyramidal cell axons. RESULTS: Layer 5 of rat neocortex, in vitro, can generate VFOs when chemical synapses are blocked. Human epileptic neocortex, in situ, produces preseizure VFOs characterized by the sudden appearance of "blobs" of activity that evolve into spreading wavefronts. When wavefronts meet, they coalesce and propagate perpendicularly but never pass through each other. This type of pattern has been described by Lewis & Rinzel in cellular automaton models with spatially localized connectivity, and is demonstrated here with 120,000- to 5,760,000-cell models. We provide a formula for estimating VFO period from structural parameters and estimate the spatial scale of the connectivity. DISCUSSION: These data provide further evidence, albeit indirect, that preseizure VFOs are generated by networks of pyramidal neurons coupled by gap junctions, each predominantly confined to pairs of neurons having somata separated by < ∼1-2 mm. Plausible antiepileptic targets are tissue mechanisms, such as pH regulation, that influence gap-junction conductance.

Safety at The William Quarrier Scottish Epilepsy Centre.

PURPOSE: We examined the yield from EMFIT bed alarms and staff response time to generalised seizure in a medium term residential assessment unit for epilepsy. METHODS: The Scottish Epilpesy Centre (SEC) has a Video Observation System (VOS) that provides continuous recording of all patient spaces (external and internal) and allows retention of clinically relevant events. A retrospective audit of daily EMFIT test records, nursing seizure record sheets (seizure type and EMFIT alert status), clinical incident reporting systems and the VOS database of retained clinical events was conducted for an 9 month period from April 1st 2016 till December 31st 2016. All generalized tonic clonic seizures (GTCS) were noted by patient, time and location and staff response time to GTCS was calculated. RESULTS: There were 85 people admitted during the audit period who had 61 GTCS. 50 events were in bed and EMFIT alert status was recorded. On 8 occasions the EMFIT did not alert: 5 events were not of sufficient duration or frequency, in 2 the patient fell from the bed early and 1 event the alarm did not trigger. The average response time to GTCS was 23s. The longest response time was 69s (range, 0-69s, sd 15.76.). CONCLUSIONS: The EMFIT bed alarm appears to be a valuable adjunct to safety systems. Within the novel environment of the SEC it is possible to maintain a response time to GTCS that is comparable to hospital based UK video telemetry units.

The movement disorders of Coffin-Lowry syndrome.

Coffin-Lowry syndrome (CLS) is an X-linked semi-dominant condition with learning difficulties and dysmorphism caused by mutations in the gene RSK2. Originally, epilepsy was reported as a feature. We and others have since described predominantly sound-startle induced drop attacks that have been labelled 'cataplexy', abnormal startle response and hyperekplexia. We sought to clarify why there should be controversy over the type of paroxysmal events. Review of the literature and our patients confirmed that each centre had studied only a small numbers of individuals (mean = 2). The type of movement disorder varied both with age and between individuals. One individual might have more than one movement disorder. One of our adult patients had several types of movement disorder and epilepsy that merged seamlessly: there was true cataplexy triggered by telling a joke, something close to cataplexy ('cataplexy') triggered by sound-startle, a predominantly hypertonic reaction varying from hyperekplexia to a more prolonged tonic reaction resembling startle epilepsy, and true unprovoked epileptic seizures. In the large database of the Coffin-Lowry Syndrome Foundation family support group, 34 of 170 (20%) individuals with CLS and known age had 'drop attacks' and an additional 9 (5%) of these had additional epileptic seizures. The onset of such events was usually after age 5 years, prevalence peaking at 15-20 years (27%). Many became wheelchair bound as a result. This unique combination of more than one non-epileptic movement disorder and epilepsy deserves further semiological and genetic study both for the patients with CLS and for the wider implications.