
 focal epilepsies account for about two - thirds of all adult epilepsy patients , and temporal lobe epilepsy ( tle ) is the most common type of focal epilepsy ( 1,2 ) .
temporal lobe epilepsy is subcategorized as mesial ( i.e. , amygdalohippocampal ) and neocortical ( i.e. , lateral ) temporal .
mesial temporal lobe epilepsy ( mtle ) with hippocampal sclerosis ( hs ) is one of the most common types of epilepsy referred for surgical treatment ; it is often refractory to antiepileptic drugs ( aeds ) , but responds favorably to surgery ( 1,4 ) .
patients with mtle - hs and intractable seizures often experience progressive behavioral changes including increasing memory deficit with the passage of time .
in addition , surgical outcome may be worse with longer duration of epilepsy or increasing age at surgery , which suggests that mtle - hs is a progressive disorder ( 5 ) .
therefore , early detection of this syndrome and its distinction from other tle syndromes has important practical implications with regard to planning an optimal treatment strategy for the affected patient . 
 
 in the current study
, we tried to compare the clinical characteristics of patients with mtle - hs with those who had tle due to other etiologies in order to identify potentially differentiating clinical characteristics between these two groups of patients . 


 in this retrospective analytic study all patients with a clinical diagnosis of tle were recruited in an outpatient epilepsy clinic at shiraz university of medical sciences , which is the only referral epilepsy clinic in south iran .
the diagnosis of tle was made exclusively by one epileptologist working at this institution ( the first author ) and based on clinical grounds ( semiology ) , electroencephalographic ( eeg ) findings and imaging , such as magnetic resonance imaging ( mri ) .
all patients were followed up by the epileptologist at our institution for at least one year ( i.e. , until may 2014 ) .
routine eeg was requested for all patients at the time of referral . in difficult - to - diagnose or
difficult - to- treat patients we often order video - eeg monitoring to ascertain the diagnosis and formulate an individualized treatment plan , accordingly .
for all patients , a 1.5 tesla brain mri ( epilepsy protocol ) was performed . 
 

we classified patients as having mts ( if they had clear signs of mesial temporal sclerosis and/or atrophy in their mri ) and those who had any other mri abnormality .
patients with dual pathology ( i.e. , mesial temporal sclerosis associated with other structural lesions ) were excluded from the study . 
 

age , gender , age at seizure onset ( i.e. , the first afebrile seizure ) , seizure type(s ) , epilepsy risk factors ( including pregnancy complications , history of febrile seizure , cns infection , significant head trauma , positive family history of epilepsy ) , eeg findings ( the most informative eeg ) , and mri findings of all patients were registered routinely .
seizure types were categorized as generalized tonic clonic seizures ( gtcs ) , complex partial seizures ( cps ) and auras .
pearson chi - square , fisher 's exact , and mann - whitney u tests were used for statistical analyses .

 until may 2014 , 2890 patients with epilepsy were registered at our epilepsy clinic .
four hundred twenty - seven patients ( 14.7% ) were diagnosed as having tle . of these ,
174 patients were eligible to enter the study ( 105 patients with mtle - hs and 69 patients with tle due to other etiologies ) .
demographic and clinical characteristics of patients with mtle - hs and those who had tle due to other etiologies are shown and compared in table 1 .
frequency of seizure types ( i.e. , gtcs vs. cps vs. auras ) was not significantly different between these two groups ( table 1 ) .
specific types of auras were significantly different between these two groups ( table 1 ) , however most auras were reported by both groups , similarly .
epilepsy risk factors were reported to be as follows ( mtle - hs vs. others ) : parental consanguinity in 41 / 30 ( p= 0.6 ) , family history of epilepsy in 18 / 10 ( p= 0.6 ) , significant head trauma in 15 / 7 ( p= 0.4 ) , cns infection in 2 / 2 ( p= 0.6 ) and pregnancy complications in 2 / 3 ( p= 0.3 ) . 
 

mtle - hs : mesial temporal lobe epilepsy ( mtle ) with hippocampal sclerosis ( hs ) . 
 

video - eeg monitoring was available in 155 patients ; and 19 patients had a routine eeg only .
eleven patients ( 10.4% ) with mtle - hs and four ( 5.8% ) with other etiologies had normal eeg ( p= 0.2 ) .
right sided , left sided or bilateral focal epileptiform discharges ( i.e. , temporal seizures , spikes or sharp waves ) were observed in 36 , 38 , and 20 patients with mtle - hs and 31 , 21 and 13 patients with other etiologies , respectively ( p= 0.4 ) . focal polymorphic delta activity or temporal intermittent rhythmic delta activity ( tirda ) was seen in 60 and 7 patients with mtle - hs , respectively .
these figures were 32 and 4 in patients with other etiologies ( p= 0.3 ) . 
 

magnetic resonance imaging ( mri ) in patients with other etiologies ( non- mtle - hs group ) showed temporal lobe tumors in 27 patients ( 39.1% ) , non - specific white matter mri abnormalities in 11 ( 15.9% ) , cavernoma in seven ( 10.1% ) , sequels of head injury in six ( 8.7% ) , arachnoid cysts in five ( 7.2% ) and other etiologies in 13 ( 18.8% ) patients .
twelve patients had dual pathology ( mesial temporal sclerosis in addition to another lesion ) .

 mesial temporal lobe epilepsy with hippocampal sclerosis is a common type of epilepsy referred for surgical treatment due to medical refractoriness . as a matter of fact
however , it has been suggested that early surgical intervention after seizure onset is an important precondition for achieving seizure - free status after surgery ( 6 ) .
therefore , early detection of this syndrome has important practical implications with regard to planning an optimal treatment strategy for the affected patient , particularly those with medically - refractory seizures . 
 
 in the current study
, we observed that earlier age at epilepsy onset ( i.e. , teenagers compared to young adulthood ) , a past history of febrile seizures and reporting affective auras ( e.g. , fear , anxiety , depression , joy , and anger ) were commonly seen in patients with mtle - hs , while auditory auras were more frequently reported by those with tle due to other etiologies .
in previous studies dominantly represented by patients with hs on mri , it has been observed that age at onset is variable ( 7 ) .
the finding that age at onset is a potential clinical variable to distinguish mtle - hs from tle due to other etiologies should be further explored in future studies . 
 

several studies have shown a significant relationship between a history of febrile seizures in early childhood and mesial temporal sclerosis . in one study , it was observed that hippocampal t2 hyperintensity after febrile status epilepticus represents acute injury often evolving to a radiological appearance of hs after one year ( 8) . having a past history of febrile seizure is a useful historical clue in favor of mtle - hs compared to tle due to other etiologies . 
 
 as the first ictal symptoms
, auras can provide important localizing and lateralizing information useful in determining the location of the epileptogenic zone ( 9 ) .
the observation that , affective auras ( e.g. , fear , anxiety , depression , joy , and anger ) were commonly seen in patients with mtle - hs , while auditory auras were more frequent among those with tle due to other etiologies , has very important clinical implications . in one study ,
the authors examined the relationship between presence of different types of auras and post - surgical outcomes in 157 patients with medically intractable mesial temporal lobe epilepsy ( mtle ) with unilateral hippocampal sclerosis ( hs ) .
the occurrence of multiple auras was not associated with post - surgical outcome ( p = 0.7 ) .
but , the presence of extratemporal auras ( e.g. , somatosensory , visual and dysphasic auras ) was significantly higher in patients with poor outcome ( 10 ) . designing future studies to investigate the relationship between presence of mesial temporal lobe auras ( e.g. , psychic symptoms , cognitive and affective auras , autonomic auras such as epigastric sensation , olfactory and gustatory auras ) versus lateral temporal lobe auras ( e.g. , vertiginous and auditory auras ) and surgery outcome in patients with mtle - hs is necessary . 


 the mainstay for making a correct diagnosis , when evaluating a patient with seizure , is having a standardized approach , particularly with regard to taking a detailed clinical history .
one may find important clues in the clinical history ( e.g. , age at onset , detailed seizure description and past history ) to make a syndromic diagnosis .
the syndromic diagnosis forms the basis for the treating physician to decide upon an appropriate management plan . 


 this was a clinic - based series and may not represent the full spectrum of tles . 


 we would like to thank neurosciences research center , shiraz university of medical sciences , shiraz , iran for supporting this study . 

 
 background : this study compares the clinical characteristics of patients with mesial temporal lobe 
 epilepsy with hippocampal sclerosis ( mtle - hs ) with those who have temporal lobe epilepsy ( tle ) 
 due to other etiologies 
 . 

 methods : in this retrospective study all patients with a clinical diagnosis of tle were recruited in a 
 referral outpatient epilepsy clinic at shiraz university of medical sciences from september 2008 to 
 may 2013 . 
 we classified the patients with tle as having mesial temporal sclerosis if they had clear 
 signs of mesial temporal sclerosis and/or atrophy in their mri and others who had any other mri 
 abnormality . 

 
 results : a total of 174 patients were studied ( including 105 patients with mtle - hs and 69 patients 
 with tle due to other etiologies ) . 
 frequency of seizure types was not significantly different 
 between these two groups . 
 earlier age at epilepsy onset ( p= 0.005 ) , a past history of febrile seizures 
 ( p= 0.010 ) and presence of affective auras ( p= 0.008 ) were commonly seen in patients with mtlehs , 
 while auditory auras ( p= 0.020 ) were more frequent in those with tle due to other etiologies . 

 
 conclusion : the mainstay for making a correct diagnosis , when evaluating a patient with seizure , 
 is having a standardized approach , particularly with regard to taking a detailed clinical history . 
 one 
 may find important clues in the clinical history ( e.g. , age at disease onset , detailed seizure description 
 and past history ) to make a correct diagnosis . 
 