Temporal lobe epilepsy has always been a controversial topic. If you look at literature over the last two decades, neurosurgeons publish more information than any other speciality about it, because the general view (rightly) is that it's a refractory disease in which surgery has great importance.
As with any other epileptic syndromes, the concept is mainly clinical, and it's diagnosis should be clinical also. But since the introduction of EEG and neuroimaging techniques, a constant trend in using them as a way to confirm the diagnosis has emerged.
This has been a great accomplishment for almost any type of epilepsy, except temporal lobe syndrome, in which standard EEG utility is very poor and more sensible (and specific) techniques such as nasopharyngeal electrodes are usually discarded because of the high frequency of artifacts.
I have to admit that this has been a constant headache for me in my day to day interaction with psychiatrists/neurologists.
So, using EBM, but also your personal experience, what is the most useful way of make the diagnosis? If you think it should only be the clinical elements (as I think also), what would be the advantages/disadvantages of trying to document the diagnosis with EEG or neuroimaging techniques?
The best way for a syndromic diagnosis is to talk with the patient or relatives. Other things is etiologic diagnosis.
As an epileptologist, the triad that is most helpful in making the diagnosis is clinical history (age at onset, risk factors, seizure semiology), EEG and a high-resolution MRI. All 3 are complementary, and each one alone can provide falsely localizing data. For example, a semiology of abdominal or psychic auras can occur with orbitofrontal lobe epilepsy; "temporal" spiking on EEG can occur in the context of posterior quadrant epilepsy (so you need EEG to make sure there are no parietal or occipital spikes); hippocampal volume loss (sclerosis) can occur with longstanding epilepsy as a secondary finding or may be part of dual pathology (dysplasia or tumor PLUS hippocampal sclerosis so you need imaging to assess extent of disease).
All in all, if the question is: does this patient have epilepsy? then clinical sense-as you rightfully suggest- is often more than enough. If the question is: does this patient have surgically remediable TLE, then history, EEG and MRI are essential.
It depends on what you are aiming at. If what you mean by making the diagnosis of temporal lobe epilepsy (TLE) is really just to diagnose TLE in contrast to other differential diagnoses, clinical elements (patient history, seizure semiology) surely are leading and may be sufficient in most (but not all) patients. If you would aim at epilepsy surgery, you would have to differentiate mesial/lateral cases, as well as "temporal plus" cases, i.e. cases with additional involvement of other regions. EEG would contribute to validation of epileptic genesis and focus localization, as well as MRI. Without, you'd probably also have to go with standard resections, which may have a worse neuropsychological outcome (although that also is a matter of debate). If I would be diagnosed with suspicion of TLE, I'd want MRI and EEG for confirmation (in addition to neuropsychological testing).
Using more or less diagnostic methods is ultimately a matter of minimizing the error rate (of diagnosis and subsequent surgical therapy). In classical mesial TLE, this error rate is probably comparably low to start with, however also (of course) not zero. Looking at long-term outcomes after epilepsy surgery for TLE supports this: While initial seizure free rate are rather high (>90%), the percentage of patients without seizure recurrence drops to 50% and less after 10 years (see Kelley et al., Neurology 2005 and Sperling et al., Epilepsy Research 2008).
epilepsy is aclinical diagnosis good history from wittens and patient in more sittings after that EEG MRI
In the diagnosis of TLE, it is very important to begin with a complete clinical history, highlighting, whenever possible, the sequence of events involved in presumed patient's epileptic seizures. We should try to answer basic questions such as: (1) is epilepsy?, (2) what type of seizures are these?, and (3) that the etiology? In this context, EEG is a fundamental tool to answer the first two questions, and MRI is very important to elucidate etiology. There are many problems about all methods (semiology, EEG, MRI), and a rational survey of all data must be employed.
History taking not only from the patient but also from the family. Always.
A definite diagnosis can only be made by invasive EEG, so EEG that records with electrodes on the brain or in the brain, and when you record seizures and see the seizure pattern on the electrodes that are located in the temporal lobe. But even then it is possible, that you will miss the seizure onset, if your electrodes happen to not be in the correct location. Another way to definitely say post-hoc that the patient had temporal lobe epilepsy is if the patient became seizure free after anterior temporal lobe resection, but that is of course no diagnostic test.
Without these invasive methods, you have to combine tests (history, MRI, EEG, SPECT and PET) and make a best possible diagnosis from the results as the colleagues above have written. As they have correctly said, it is imperative that you keep in mind, that no diagnostic test has a perfect sensitivity or specificity, in fact for some features of epilepsy the reliability of your diagnostic tools is very low. So don't say that a patient has TLE if all you know is that the patient does have seizures and you found one epileptiform discharge over the temporal lobe. That would be too little information. If you have abdominal auras evolving into automotor seizures, you have temporal seizure patterns on EEG and a ipsilateral mesial temporal sclerosis on MRI, then you can make the diagnosis of TLE with a higher reliability but again, as Lara Jehi has pointed out, you only increase the likelihood of a correct diagnosis, you cannot be perfect.
A thorough history including the key features like epigastric auras etc. will lead you in the right direction. A high resolution MRI of the brain in search of hippocampal sclerosis or any other structural pathology is obligatory. To me the gold standard in the diagnosis of TLE still is a prolonged video-EEG-monitoring during which we will hopefully recorded seizures as well as interictal spikes.
TLE is most common form of epilepsy; also, most common form of intractable or medically refractory epilepsy too. The major reason for it being most common is its relatively more susceptibility to hypoxia, ischemia and injury. Further, TLE can manifest in innumerable forms, ranging from GTCS to subtle or microseizures; in many instances, TLE can manifest even in unnoticeable alterations in behavior that confounds its diagnosis till late stage; also being mistaken for behavior or psychiatric states.
EEG has high degree of yield of abnormalities in TLE, if performed meticulously especially obtaining an additional sleep recording as well. In my setup, the EEG supports TLE diagnosis in more than 95%.
MRI may commonly exhibit hippocampal volume abnormalities.
a clinical semiology of limbic structure involvement an aura epilepsy protocol MRI and EEG are good enough if drug refractory Video EEG with documentaion is necessary
The answer is very simple. The diagnosis of TLE is made by a detailed interview to the patient (auras from TL origin) and to the family (discognitive changes and automatisms). EEG is very helpful to localize the interictal discharges and to confirm the clinical diagnosis. In term of the etiology, MRI is absolutely the method of choice and you are probably right in the diagnosis when the study shows a clear cut hippocampal sclerosis or another type of lesion on the Temporal lobe. Of course there are some exceptions to the rules, but you are almost 100% sure when the three elements are in agreement. Probably the MRI, for me, is the best biomarker of TLE.
The concept "accurately" add the issue that you need to know exactly where the seizures are coming from. Video-EEG confirms the diagnosis of epilepsy. The correlation between the clinical manifestation and the EEG is very helpful too. But again, if the MRI shows a lesion in the Temporal lobe, the diagnosis was done.
The problem is when the MRI is absolutely normal, but this is another discussion...
My answer to Q of how to diagnose TLE is mainly from the critical analysis of the history from the patient (during pre ictal and post ictal periods) and from the witnessed family (during ictal period). This may be straightforward if the seizures are stereotyped repeated.
Scalp EEG will help in confirming the diagnosis, but it may be negative.
MRI is helpful to look for a lesion in the temporal lobe, but it may be normal.
I recommend Video-EEG for 2 reasons; 1 if there was issue about the diagnosis and in fact it can help in some patients who has psychiatric problem and it is important to role out psudo-seizures, and 2 if surgery is in the process.
In three words: I agree with die short answer of Stefan Seidel: 1. History, 2. Video-EEG 3. MRI to find out the main symptoms/signs and the diagnosis of temporal lobe epilepsy. Finally the therapeutic effect helps a bit, too.
Epilepsy is not a disease. It is only sign or syndroma of neuronal overexcitation because different causes in brain, in body and in enviroment. Very important is the etiological diagnosis!
Thank you all for your answers. It's been a long and fruitful debate, but it's also been suffering from the same bias as modern literature: its focus on everything that hast to be with presergury evaluation.
To put the question in context, I may say that I'm a psychiatrist in a hospital public in Chile. Even if our country is developed by most standards, public health resources are very limited, and even private facilities are trending to more and more expensive ways of working. So, in fact, the trend is our country is for people to movilize from private to public health systems. But, very unfortunately, none of them has the experience (or income) to offer what they really did want to offer.
Centering in my experience (I'm a psychiatrist in a national-reference speciality hospital), even if we have many more resources than small hospitals around the country, they are still very insuficient.
When we are in fron of a patient diagnosed with temporal lobe epilepsy, we did it just because of history. Afterwards, we have to take the decision if to interconsultate a neurologist (real epileptologists are very few still). Sometimes we do, and sometimes don't. The great majority of times, It's been just a waste of time, because neurologists use to take the EEG (and superfice standard EEG by the way!) as the gold standard, and, if it's normal, they told us that "the patient just doesn't have epilepsy!" But, what they don't is what is the alternative interpretation of the disease! So, they leave us to make the diagnosis, but they con't believe in our interpretations.
The only instrument to making the diagnosis we have is standard EEG. We don't have anterior temporal lobe electrodes, nor the most controversial sphenoidal of nasopharyngeal electrodes. So, our capacity to detect deep electric alterations is almost nule (we have to depend on the focal crisis secondarily generalizating, and, maybe we are coming too late in the evolution of the disease). It gives opportunity to misunderstandings too, as it happened with a patient who started having simplex visual hallucinations (originating in the temporal-parietal conjunction), and the conclusion was that they were not of epileptic origin because standard EEG was normal.
About video-EEG, I think it's a great tool. But, from my point of view, it has some flaws. The first premise it has to fulfilled, is that epileptic crises has to be easy identifiable. IN the majority of tonicl-clonic disorders, that would be easy to do. But, what happens when mottor features are less prominent, or, moreelse, frankly absent from the semiology of the crisis? You don't have to remember that, taken to an extreme, a single olfactive hallucination could be an epileptic bout. I doubt so much the patient should consult physicians for that, but it's to make my point of how variable epilepsy can be.
Let's remember temporal lobe epilepsy has a many way of manifestating, from elementary hallucinations, to memory disorders not atribuible to epileptic crises, but to its activity, to crepuscular episodes in which the patient disorientates itself, to psychotic confuse episodes which are a fundamental (afortunately not so frequent) part of the psychopathology of TLE, and to real lucid psychoses which are not part of the epilepsy itself, but more something of a subproduct of it.
All this manifestations can't be so easily view in a video-EEG. So, the technique is very useful when motor symptoms predominate, or at least, when some of them, althought albeit, can be easily recognized.
The first aspect of biological study, neuroimaginings, it's very useful to identify causes of the epilepsy. As Nikola assertively said, epilepsy is a group of syndromes, so it would be more accurate to talk of the "Epilepsies", as a group of diseases with many caracteristhics in comon, but very different aethiologies. Neuroimagings should be the first step to advance in this area, but also should genomics.
But, personally, I think this is really futile if we don't agree first about right ways to diagnose the group of diseases we calle epilepsy. If we don't do this first, It will be wasted time.
And here comes a very tricky question for you all. Epileptology has now been conceptualized as an emergent subspeciality of neurology. But I had to admitt that I strongly disagree, partly because of the enormous amount of epileptics we have to control in the Psychiatric Hospital because neurologist don't care about them (sometimes because they don't believe in the diagnose, and sometimes because they try the best they can, but burocracy is something capable of eating every good intention).
One proposal (clearly radical) is that epileptology should be a psychiatric subspeciality. That would demand to focus the postgraduate training in learning motor aspects of epilepsy, and some aspects of sistematizations (in which Psychiatrist, I admitt, are not very versed).
The last proposal, and the one I add myself, is that epileptology should be a subspeciality open to psychiatryst as to neurologist. To be good epileptologist, everyone has to learn something important. The neurologist has to learn the "language" of the psychopathology, in which sometimes which the patient said is not so important as HOW she said it. And psychiatryst hast to learn some of systematization, and in-detail neurologic exam, and the basics of some neurologic syndromes.
¿What do you think about my proposals?
ASee you!!!
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