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|Year : 2018 | Volume
| Issue : 2 | Page : 323-325
'Stance' in epilepsy - our stance on the current classification of seizures
Sunil Pradhan, Madhura Mulmuley
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Web Publication||15-Mar-2018|
Dr. Sunil Pradhan
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Pradhan S, Mulmuley M. 'Stance' in epilepsy - our stance on the current classification of seizures. Neurol India 2018;66:323-5
The oldest known and documented traditional cultures of the world, such as Vedic, Babylonian, Latin and Greek, have carefully observed descriptions of epilepsy, which more than anything else compel us to think of this disorder as much a social disorder as it is medical. The episodes of seizures are often dramatic and frightening to the observer. This might be the reason why a description of epilepsy is found in all civilizations of the world, whether or not the medical aspect of life is touched upon by them. However, one cannot ignore the fact that most of the ancient wise men thought of epileptic attacks as the result of possession or invasion of the body by some supernatural evil influence requiring religious or socio-cultural approaches such as exorcism, incantation or their regional variations, like “Jhar-Phoonk” in India. In our opinion, the major contribution to this universal ancient belief could be the peculiar phenomenon that occurs in a subset of seizure attacks, that is, the development of unconsciousness while the body stance or the erect posture is maintained. This is true for epilepsies such as focal, absence or myoclonic seizures. Any automatic activity in the body, while the patient is unaware of the surroundings (and, is therefore unconscious) but is standing or moving with an erect posture, is quite scary and is noticeable as an unnatural phenomena to a lay man, rather than a disease. This is because the unconscious state is generally perceived as a state where the body stance is lost. It, therefore, appears to be quite logical to pay more attention to an intact or lost erect body stance while dealing with the recognition of different forms of epilepsies.
Whenever a disease is classified, our aim is usually to simplify the complexities of the disease but at the same time to place its salient features in the right perspective and the right order., In the case of epilepsy, however, there is an additional feature that needs to be kept in mind, and that is the symptomatology that a lay man can understand because it is that lay person who often observes the actual seizure rather than a medical professional., It is perhaps keeping this fact in mind that the current classification has replaced some of the older terms with the new ones; for example, the term 'partial' is now replaced by the term 'focal'., In our opinion, any classification which emphasizes the first-hand account of the seizure, as given by the bystanders, must place a high degree of importance to whether or not the patient had lost his erect posture or body stance during the seizure episode. This is the first thing that any accompanying person would observe before the development of other finer elements that may help in deciding the particular type of seizure. Thus, the simple observation of a maintained or lost stance would quite narrow down the differential diagnoses of various forms of epilepsies to nearly half. We, therefore, feel that the body stance, whether maintained or lost, should be the foremost element in the classification of epilepsies. A pathway down the history of classification of epilepsies shows that different components of the seizure semiology are given varied importance at different times. Serial observations, however, suggest that whenever a difficult scientific term was used, it needed to be corrected to a simpler and easily understandable term in due course of time.
The International League Against Epilepsy (ILAE) has suggested several classifications in the past to simplify and categorize different forms of seizures, and at one point of time, it thought it to be more appropriate to classify seizure episodes and epilepsy separately to correctly accommodate childhood and other epileptic syndromes. In 1981, it dichotomized epileptic seizures into partial and generalized groups as shown in [Figure 1]. It is clear from this figure that the major emphasis at that time was on the onset of seizure, focal or generalised, and on the subsequent observable appearance of the seizure.
|Figure 1: The 1981 International Classification of Epileptic Seizures (ICES)|
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Subsequently, it was realised that the onset of seizure is sometimes missed by the observers, and the etiology of the disease may also throw some light on focality. Therefore, in 1985 and 1989, ILAE came out with newer classifications of epilepsies and epileptic syndromes with replacement of the term partial with “lateralization related,” to incorporate etiologic evidence of focality into it. It was a dual dichotomy scheme. In terms of semiology, it divided epilepsies into those with focal seizures versus generalized seizures; and, in terms of etiology, to idiopathic versus symptomatic seizures [Figure 2].
|Figure 2: The 1985 International Classifications of Epilepsies and Epileptic Syndromes (ICE)|
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In 2010, the ILAE highlighted two main points in the proposal. One was the redefinition of focal and generalized seizures. The term “focal” was officially used to replace the word “partial”. The other was the reorganization of epilepsies. In this classification, more clarity is given to the state of consciousness by adding the word 'awareness' to it. As the classification, was more oriented towards seizures rather than to epilepsy as a disease, etiological considerations were not present [Figure 3].
In 2017, the ILAE released a new classification of seizure types, largely based upon the existing classification formulated in 1981. The differences include specific listing of certain new 'focal' seizure types that were previously in the 'generalized' category only, the use of 'awareness' as a surrogate for consciousness, the emphasis on classifying focal seizures by the first clinical manifestation (except for altered awareness), and the addition of a few new generalized seizure types. This classification could also classify some seizures when the onset was unknown, and rename certain terms to improve clarity of meaning [Figure 4].
The evolution of epilepsy classification
As we have seen from the above discussion, in all these years, the classification of epilepsy has evolved in many ways. The initial concept of 'generalised' and 'focal' seizures was modified. A new concept of 'awareness' was given more emphasis and grouping was done based on 'preservation or loss of awareness'.
In all these modifications, however, one important component of seizure semiology, that is, 'posture' or 'stance' has been overlooked. In many types of epilepsies, the patient does not lose his upright stance, for example, in generalized-onset non-motor seizure like absence seizure, in focal-onset seizure with unawareness (previously complex partial seizure), or in focal myoclonic, autonomic, and sensory, cognitive seizures.
Stance of a patient forms an important component in seizure history, which can be easily observed by relatives or bystanders. In seizures without loss of posture, patients and caregivers can be assured about a decreased risk of physical injury to the patient that may be precipitated by a fall in an outdoor location.
With respect to the prevalence of common epilepsy types, generalised tonic-clonic seizures (GTCS) and complex partial seizures (CPS, focal with unawareness) are both commonly encountered. In these epilepsies, a very important difference is the maintenance of stance in focal seizure with unawareness (CPS), and the loss of stance in GTCS. This difference is not highlighted in any of the previous classifications.
The maintenance of stance or posture in any particular type of seizure may point to the area involved or spared during the electrical activity. For example, in absence seizures, the maintenance of posture is presumed to be because the seizure activity does not spread to involve more resistant brainstem postural mechanisms.
Based on the above discussion, we propose a slight modification in the recently outlined classification of epileptic seizures by ILAE in 2017. The inclusion of maintenance or loss of stance in the classification will provide more clarity about the seizure type to the medical as well as non-medical community. The proposed classification is shown in [Figure 5]. As is true of the existing classification, the new proposal is a practical one and not based on fundamental mechanisms. The inclusion of 'stance' adds to the practicality of current classification, as it forms a very important and easily observable component of the seizure semiology.
|Figure 5: The proposed classification for seizures with respect to stance|
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]