Focal Epilepsy
Mazen 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 Aura
Most 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,
• Bicycling
• Pelvis
proximal, tonic, bizarre looking
movement
thrusting and other sexual automatism
• Vocalization
• Contralateral
• Fear
head and eye deviations
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
days
Absence, “staring”: Prolonged up to few
•
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.”