Critique of the 2017 epileptic seizure and epilepsy classifications.

This article critiques the International League Against Epilepsy (ILAE) 2015-2017 classifications of epilepsy, epileptic seizures, and status epilepticus. It points out the following shortcomings of the ILAE classifications: (1) they mix semiological terms with epileptogenic zone terminology; (2) simple and widely accepted terminology has been replaced by complex terminology containing less information; (3) seizure evolution cannot be described in any detail; (4) in the four-level epilepsy classification, level two (epilepsy category) overlaps almost 100% with diagnostic level one (seizure type); and (5) the design of different classifications with distinct frameworks for newborns, adults, and patients in status epilepticus is confusing. The authors stress the importance of validating the new ILAE classifications and feel that the decision of Epilepsia to accept only manuscripts that use the ILAE classifications is premature and regrettable.

Epileptiform Discharges Recorded as Monopoles and Dipoles in the EEG: A Practical Approach to Differentiate Tangential and Radial Generators Using Electrode Position Versus Voltage Graphs.

SUMMARY: Differentiating dipoles (tangential generators) from monopoles (radial generators) in routine EEG reading can be difficult. The polarity of sharp waves seen on surface EEG will change depending on the generator being located at the wall of the sulcus versus the crown of a gyrus. In this article, the authors introduce visual rules that may be used to determine polarity and estimate the localization of potentials during analysis of the EEG. They also review a practical approach to differentiate monopoles (radial generators) from dipoles (tangential dipoles) in the surface EEG using "electrode position versus voltage graphs." Finally, the authors illustrate examples of dipoles and monopoles with focal spikes located in the following locations: (1) bipolar spikes located in the anterior bank of the central sulcus, (2) bipolar spikes located in the posterior bank of the central sulcus, (3) monopolar spikes located in the crown of the precentral gyrus, (4) bipolar spikes with a vertically oriented dipole originated within the temporal (inferior) bank of the Sylvian fissure, and (5) monopolar spikes located in the convexity of a temporal gyrus. In summary, this article discusses electrographic features of spikes localized in various fissures and gyri and provides practical rules that permit the identification and location of dipoles and monopoles in standard scalp EEG recordings.

Ictal blinking triggered by isolated spikes as the only manifestation of seizures.

OBJECTIVE: To describe blinking as the only manifestation of seizures from isolated focal and generalized cortical spikes and investigate the relationship between blinks and epileptic discharges. METHODS: We measured the latency from the onset of spikes to the onset of blinks in two patients using electroencephalogram (EEG) and an electrooculogram (EOG), and calculated the median latency in both cases. We analyzed the latency from spike onset to the onset of additional specific eye movements, seen only in the second case. To determine the frequency of spontaneous blinks (not triggered by spikes), we defined a "control point" at 45 s following a random spike for the first case. We tested for statistically significant associations between latencies of blinks (Case 1) as well as between latencies of blinks and specific eye movements (Case 2). RESULTS: A total of 174 generalized spike-waves followed by a blink were analyzed in the first patient. Approximately 61% of the blinks occurred within 150-450 ms after the onset of the spike. Median latency for blinks following a spike was 294 ms compared to 541 ms for control blinks (p = .02). For the second patient, a total of 160 eye movements following a right occipito-parietal spike were analyzed. The median spike-blink latency in the second case was 497 milliseconds. Median latencies of spike onset to contralateral oblique eye movements with blink and left lateral eye movements were 648 and 655 milliseconds, respectively. CONCLUSIONS: Our study shows that isolated cortical spikes can induce epileptic seizures consisting exclusively of blinks. These findings emphasize the importance of careful EEG and EOG analysis to determine blinking as the only ictal phenomenon. We additionally describe a new technique to prove the temporal relationship between cortical discharges and a specific movement when, in addition to the movements triggered by a spike, the same movement is also spontaneously performed by the patient (in this case, blinking).

Could the 2017 ILAE and the four-dimensional epilepsy classifications be merged to a new "Integrated Epilepsy Classification"?

Over the last few decades the ILAE classifications for seizures and epilepsies (ILAE-EC) have been updated repeatedly to reflect the substantial progress that has been made in diagnosis and understanding of the etiology of epilepsies and seizures and to correct some of the shortcomings of the terminology used by the original taxonomy from the 1980s. However, these proposals have not been universally accepted or used in routine clinical practice. During the same period, a separate classification known as the "Four-dimensional epilepsy classification" (4D-EC) was developed which includes a seizure classification based exclusively on ictal symptomatology, which has been tested and adapted over the years. The extensive arguments for and against these two classification systems made in the past have mainly focused on the shortcomings of each system, presuming that they are incompatible. As a further more detailed discussion of the differences seemed relatively unproductive, we here review and assess the concordance between these two approaches that has evolved over time, to consider whether a classification incorporating the best aspects of the two approaches is feasible. To facilitate further discussion in this direction we outline a concrete proposal showing how such a compromise could be accomplished, the "Integrated Epilepsy Classification". This consists of five categories derived to different degrees from both of the classification systems: 1) a "Headline" summarizing localization and etiology for the less specialized users, 2) "Seizure type(s)", 3) "Epilepsy type" (focal, generalized or unknown allowing to add the epilepsy syndrome if available), 4) "Etiology", and 5) "Comorbidities & patient preferences".