**2.4 The classification**

It is a common practice, among epileptologist, to subdivide the refractory epilepsy cases into temporal lobe epilepsy (TLE) and non-temporal lobe epilepsy (NTLE). The former also constitute two distinct groups, namely, mesial temporal lobe epilepsy (mTLE) and neocortical temporal lobe epilepsy (NeTLE), according to the clinical and radiological manifestations. Both mTLE and NTLE shared similar pathological substrates (**Table 1**) apart from the mesial temporal sclerosis only found in the former. The TLE patients usually present with complex partial seizures, with or without generalized seizure, depending on the neuronal network involved. Though a minority of these TLE will became seizure free after repeated drug trials [15], most of the patients will run a clinical course of refractory seizure attack, and indeed, they form the most well-known surgically remediable epilepsy syndrome [19].

For the non TLE cases, the clinical and radiological features are diverse and also depend on the underlying etiologies or pathological substrates. In general, the seizure semiology is less well defined and the MRI abnormalities are variable and they are challenging in the perspective of seizure focus localization. Usually concerted effort and multi modalities investigations (in phase 1 of presurgical evaluation) are required [20].


### **Table 1.**

*Temporal lobe epilepsy (TLE) pathology.*
