Focal epilepsies

Question 1

Clinical features favoring mesial temporal lobe epilepsy (9)
Timing (2)
Pertinent Past history (6)

Answer 1

Clinical Features favoring mesial temporal lobe epilepsy:
Timing:
- Early age of onset
- well-controlled seizures in early childhood but re-emergency of refractory epilepsy in adolescence / early adulthood
Pertinent past history
- History of complex febrile seizures
- Congenital brain malformations
- CNS infections
- Tumors
- Head trauma
- Perinatal injury

Question 2

Clinical features favoring lateral temporal lobe epilepsy
Timing (2)
Imaging (2)

Answer 2

Clinical features favoring lateral temporal lobe epilepsy
- later age of onset
- absence of early risk factors
- absence of hippocampal atrophy (or other structural findings)
- more common negative functional brain imaging

Question 3

Why is it important to differentiate lateral versus mesial temporal lobe seizures?

Answer 3

• Mesial temporal lobe seizures often will be abolished after standard temporal lobectomy or selective amygdalohippocampectomy
• Lateral temporal lobe seizures will often require sEEG to map eloquent cortex and tailor a surgical resection.

Question 4

Semiology suggestive of MESIAL temporal lobe seizures
- Aura (4)
- Ictal/postictal (4)

Answer 4

Often have aura
- rising epigastric discomfort
- fear
- olfactory feeling
- autonomic signs (pallor, flushing, mydriasis)
Ictal
- Contralateral dystonic posturing of hand
- ipsilateral hand automatisms
- speech arrest (if dominant)
- Postictal (IL) nose wiping

Question 5

Semilogy suggestive of LATERAL temporal lobe seizures
- Aura (2)
- Ictal/postictal

Answer 5

Aura:
- vertigo
- auditory or visual hallucinations
Ictal:
- Evolve early into unilateral clonic activity
- Early head turning

Question 6

EEG features of mesial vs lateral temporal lobe seizures

Answer 6

Mesial temporal lobe seizures
- rhythmic theta-range ictal discharges
- initial focal temporal rhythmic activity <5 Hz > 5-7Hz sphenoidal maximum theta activity
Lateral Temporal lobe seizures
- high incidence of repetitive epileptiform discharges at onset
- transitional sharp wave at ictal onset

Question 7

% of patients with MTS and without diagnosis of epilepsy

Answer 7

14%

Question 8

Classic EEG seizure finding for MTS

Answer 8

Anterior temporal rhythmic theta or alpha that exceeds 5 Hz within 30 seconds of seizure onset

Question 9

Classical seizure semiology for MTS

Answer 9

Aura:
- abdominal aura (nausea, pressure, buterflies, rising epigastric sensation)
- Fear
- Unpleaseant taste or smell
Seizure
- Oralimentary automatisms
- Ipsilateral limb automatisms
- Autonomic phenomenon

Question 10

Imaging and MTS
- Most common feature
- most SPECIFIC feature

Answer 10

• Most common: hippocampal hyperintensity on T2-weighted seauences
• Most specific: Hippocampal atrophy (usually on T1)

Question 11

Way you can diagnose MTS even with no MRI features

Answer 11

PET can show temporal hypometabolism

Question 12

subcategories of each type of FCD
Type I (3)
Type II (2)
Type III (4)

Answer 12

First two think “balloons on sticks”
Type I
* Ia: abnormal vertical alignment of neurons
* Ib: abnormal horizontal alignment of neurons
* Ic: both horizontal and vertical abnormalities
Type II
* IIa: dysmorphic neurons without balloon cells
* IIb: dysmorphic neurons with balloon cells
Type III
* IIIa: mesial temporal sclerosis (MTS)
* IIIb: glioneuroal tumors (DNET, ganglioglioma, etc)
* IIIc: vascular malformations (CCM, AVM, etc
* IIId: prenatal or perinatal ischemic injury, TBI, and scars due to inflammatory / infectious lesions

Question 13

What can these findings on MRS can be associated with
Reduction of NAA / (choline+Creatinine) ratio
Increased Creatine, phosphocreatine, and choline
Rise in lactate

Answer 13

Reduction of NAA / (choline+CR) ratio: Epileptogenic foci
Increased Creatinine, phosphocreatine, and choline: Gliosis
Rise in lactate: can be seen postictally (ipsilateral, up to 6.5 hours)

Question 14

In TLE, what type of memory is primarily affected?

Answer 14

Declarative memory (memory of specific facts)