Focal EpilepsyMazen Al-Hakim, M.D.

• Focal Epilepsy

• Localization related

• Partial seizures.

• Temporal Lobe Epilepsy (TLE) is the most common type

• Hipocampal Sclerosis (HS)

• (Mesial Temporal Sclerosis) is the most common cause of TLE

• HS Pathogenesis is uncertain

1.) Febrile Seizures (one study 54/67)

2.) Genetic Factors

3.) ?Limbic Encephalitis (Adult onset)

Other Etiologies for Focal Epilepsy

• CNS Infections

• Perinatal Injury

• Cortical dysplasia

• Vascular Malformations

• TBI

• Stroke

• Tumor

Etiology is age related

• CVA, Tumor: Adult

• Perinatal Injury: Infancy-Childhood

• Cortical dysplasia: Average 7 year-old

• TBI: young adult

• In 25%, Etiology is unknown

• In surgery: Cortical dysplasia, Microgyria, gliosis

Temporal Lobe Epilepsy

• Most common focal epilepsy

• Most cases are mesial temporal, less common, neocortical

Mesial Temporal Lobe Epilepsy

• HS: the most common

• Encephalitis, including Limbic

• Trauma

• Tumor (glioma, hamartoma)

• Perinatal Injury

• Vascular Malformation

Clinical Features

• Most common: Focal dyscognitive seizure (complex partial seizure)

• One third, secondary generalization

Epileptic AuraMost common:

• Rising epigastric sensation

• Deja Vu

• Ja mais Vu

• Fear

Less common:

• Smell or taste sensation

The patient remembers the aura

Automatism in 60%

• mild, repetitive, stereotyped, purposeless

• Hands: picking, fidgeting, fumbling

• Mouth: chewing, lipsmacking

Laterlizing Symptoms• Unilateral Automatism: Ipsilateral

• Dystonic Posturing: Contralateral

• Head Turning

• Initially: Ipsilateral

• Later: Contralateral

• Contralateral clonic jerking is rare

Less Common Symptoms

• Vocalization

• Laughing

• Crying

• Fear

• Hyper-motor (walking, running away)

Postictal Symptoms• Confusion for few minutes

• Psychosis

• Hemiparesis

• Aphasia

• Nose wiping by ipsilateral hand

• Postictal wandering (nonspecific)

• Tachycardia or less likely bradycardia

Clinical Course

• 80% of TLE with HS starts before the age of 16

• Progressive Disorder: Particularly with younger onset and history of febrile seizure

• Intractable: 60-90%

• Consider surgical intervention

EEG• Interictal Temporal sharp waves in anterior

and mid temporal leads (F7/F8, T1/T2, and T3/T4)

• In 1/3 patients, bilateral independent sharp waves

• Temporal Intermittent Rhythmic delta activity (TIRDA): 25-40%

• Ictal EEG: Rhythmical and theta with post-ictal slowing

MRI Findings

• (Need high resolution coronal sections)

• Hipocampal atrophy with T2 signal

• Signal without atrophy is nonspecific, can be seen in 30% otherwise healthy

• Bilateral abnormalities in 20%

Neocortical TLE• Clinical overlap with mesial TLE

• Aura: Auditory hallucinations or distortions

• Complex visual hallucinations

• Vertigo

• Automatism, less common

• NO Epigastric Sensation

• EEG: sharp waves are usually posterior temporal

Frontal Lobe Epilepsy

• 30% of patients having surgery

• Etiologies are similar, except for HS

• Symptoms may not reflect the origin

• (eg, seizure coming from orbitofrontal cortex spreads to mesial temporal lobe causing TLE-like symptoms)

Frontal Lobe Seizures

• Short: Less than 30 seconds

• Nocturnal

• Seizure cluster or SE are common

• Brief or absent postical confusion

Frontal Lobe Seizures• Hypermotor, proximal, tonic, bizarre looking

• Bicycling movement

• Pelvis thrusting and other sexual automatism

• Vocalization

• Contralateral head and eye deviations

• Fear and anxiety, but no epigastric sensation

Frontal Lobe Seizures, Continued

• Patient might be awake

• Primary motor cortex: Contralateral motor seizure

• Supplementary motor cortex: Asymmetric tonic movement “Fencing posturing”

• Speech arrest

• Bilateral clonic movement without LOC

• Frontal Absence, “staring”: Prolonged up to few days

• EEG yield is low, 29%

• 30% have no diagnostic EEG

• Large area of frontal lobe is inaccessible to surface electrodes and rapid spread of seizure to another area

Occipital Lobe Epilepsy

• 2-8%

• Usually tumor, vascular malformation or developmental

• 80% visual symptoms

• Visual hallucinations (simple or complex)

• Visual distortions (Micropsia, Macropsia, Metamorphopsia, Dyschromatopsia)

• Cortical blindness

Parietal Lobe Epilepsy

• Uncommon

• Symptoms:

• Sensory

• Motor

• Anxiety

• Automatism, similar to TLE

• Etiology: Tumor, Vascular, gliosis

Revised terminology by ILAE

“Generalized epileptic seizures are conceptualized as originating at some point within, and rapidly engaging, bilaterally distributed networks. Such bilateral networks can include cortical, and subcortical structures, but do not necessarily include the entire cortex. Although individual seizure onsets can appear localized, the location and lateralization are not consistent from one seizure to another.”