A discussion on pediatric posterior head region epilepsy, etiopathogenesis, clinical features and management.

1. Perinatal Insult and Refractory
Posterior Cortex Epilepsy (PCE):
Approach and Management.
Dr. Pramod Krishnan,
Neurologist and Epileptologist,
Manipal Institute of Neurological Disorders,
Bangalore.

2. Definition
 Epilepsies arising from the occipital lobe or the
adjacent portions of posterior temporal and parietal
lobe are called posterior cortex epilepsy (PCE).
 Being less common than other focal epilepsies,
studies are few, especially in children.
 Available studies on PCE include different etiologies.

3. Introduction
 Hypoxia and hypoglycaemia that occur perinatally
can cause extensive damage to the brain and can lead
to chronic epileptic seizures.
 The resultant disorder is characterised by seizures of
one or more types associated with mental retardation,
visual and other severe neurological impairments.

4. Etiopathogenesis

5. Etiopathogenesis
 The immature brain is more seizurogenic than the
mature brain as evidenced by the high incidence of
seizures in the first year of life.
 This reflects the high risk of exposure to cerebral
insults and a higher susceptibility of the immature
brain to generate seizures as a reaction to injury.
 Brain is more vulnerable to ischemic insult in theBrain is more vulnerable to ischemic insult in the
presence of hypoglycemia.presence of hypoglycemia.

6. Epileptogenesis following perinatal insult
Rakhade SN, et al. Nat Rev Neurol. 2009

7. Neurotransmitter and receptor maturation during development.Neurotransmitter and receptor maturation during development.
Rakhade SN, et al. Nat Rev Neurol. 2009

8. In term neonates
 Hypoxic-ischemic injury causes watershed lesions in
the PCA territory or border zone between MCA and
PCA territories.
 Greater perfusion in the apices of the gyri than in the
cortex at the depth of the sulci.
 Cortex at the depth of sulci are more susceptible to
hypoxic injury and undergo atrophy with relative
sparing of the apex.
 This is called 'Ulegyria' or ‘mushroom gyri’.

9. Pathologic specimen: Bilateral Ulegyria due to perinatal hypoxic injury

10. •Ulegyria is seen
over the parietal
association cortex,
with variable
extension to the
occipital, central
and less often, the
temporal areas.
•Coexistence with
hippocampal
sclerosis is reported.
•Should be
differentiated from
polymicrogyria.

11. Prevalence
 In a series of 62 children operated for PCE, 33% had
history of hypoxic insult, but only 9 (14.5%) had
evidence of gliosis on HPE.
Liava et al. Epileptic Discord 2014.Liava et al. Epileptic Discord 2014.
 10/ 42 patients in a series of occipital lobe epilepsy10/ 42 patients in a series of occipital lobe epilepsy
had history of perinatal hypoxia.had history of perinatal hypoxia.
Salanova V, et al. Brain 1992.Salanova V, et al. Brain 1992.
 Ulegyria is noted in 30% of children operated for PCE.
Usui N et al. Epilepsia 49(12): 2008.

12. Etiopathogenesis
 ‘Cortical scars' alone do not cause epilepsy.
 Seizures are most likely generated within ‘acquired
cortical dysplastic changes’ which have progressed
over time after the initial hypoxic ischemic event.
 Children with perinatal hypoxic injury often have a
history of perinatal seizures, followed by long periods
of seizure freedom, before the onset of epilepsy.

13. Neonatal hypoglycemia
 This is often secondary to perinatal hypoxia.This is often secondary to perinatal hypoxia.
 Hypoxia, and hypoglycemia (which alone rarelyHypoxia, and hypoglycemia (which alone rarely
causes brain injury), usually act together.causes brain injury), usually act together.
 MRI changes in perinatal hypoxia likely includes
those caused by hypoglycemia.
 Hypoxic injury involves the parieto-occipital and to
some extent the fronto-temporal junctions,
hypoglycemia involves only the occipital region.

14. Clinical features

15. Patient P
 24/F, NCP, FTVD.
 Delayed cry at birth and neonatal seizures.
 AEDs for 1 year.
 Normal development except for visual impairment in
left field and strabismus.
 Seizures since 10 years of age.
 Refractory: 1-2/ month, on OXC, LEV, CLB.
 Learning difficulty. Poor scholastic performance.

16. Clinical features
 Many children have a history of perinatal hypoxia and
neonatal seizures but such history may be lacking.
 Usually, this is followed by months or years of seizure
freedom followed by onset of epilepsy.
 Clinical features can be divided into those of occipital
lobe seizure origin, and those from ictal spread.
 Seizure frequency is high, even daily.
Salanova V, et al. Brain 1992.
Liava et al. Epileptic Discord 2014.

17. Clinical characteristics
Usui N et al. Epilepsia 49(12): 2008.

18. Patient P: semiology
 Blindness of left visual field.........tonic head and eye
deviation to the left with preserved consciousness.
 Sometimes leads onto behavioural arrest and
unresponsiveness, lasting 20-30 seconds followed by
oral and bimanual automatisms.
 Rarely, loss of posture and fall.
 Rare SGTCS. Clustering was present.
 Right occipital to---------mesial temporal semiology.

19. Seizure semiology: AuraSeizure semiology: Aura
 Auras are reported by atleast 2/3 of patients.
 Patients with mental subnormality may not report
auras, but hints of visual auras can be often observed
like sudden expression of fear, unexplained sudden
laughter, putting hands to eyes.
 Auras are sometimes the only signs of focality.
Salanova V, et al. Brain 1992.
Liava et al. Epileptic Discord 2014.

20. Seizure semiology: Aura
Aura Type Comment
Positive elementary visual
hallucination
Most common. May be
lateralising. Occipital lobe.
Amaurosis
May be lateralising. Occpital
lobe.
Complex visual hallucinations,
illusions
Less common. T-O or P-O
region.
Fear, unreality, vertigo, paresthesias Rare. T-O region.
Salanova V, et al. Brain 1992.
Liava et al. Epileptic Discord 2014.

21. Semiology: AutomatismsSemiology: Automatisms
 Ictal spread to mesial temporal or frontal regions.
 Automatisms indistinguishable from those of patients
with TLE have been reported in 29-88% of patients
with occipital lobe epilepsy.
 Focal motor activity is seen in as many as 38-47% of
these patients.
Salanova V, et al. Brain 1992.
Williamsonj PD et al. Annals of Neurology 1992.

22. Seizure semiology
Infantile spasms
Most frequent type in younger children.
Tonic seizure may be symmetric or
asymmetric.Tonic seizures
CPS/ atypical absences Common type in older children, adults.
Focal seizures,
contralateral to the lesion
side.
Epileptic nystagmus (oculoclonic).
Rapid eyelid blinking.
Tonic eye deviation +/- head deviation.
Convergent strabismus.
Oculogyric/ Opsoclonic movements.
Ipsilateral head deviation is uncommon.
SGTCS, status epilepticus Infrequent.

23. Seizure semiology
 30-40% of patients have two or more seizure types.
 Different seizure types in a single patient may indicate
different areas of seizure origin, or different routes of
seizure spread from a single focus, leading to false
localisation.
 Many of the disabling clinical manifestations result
from the spread of the seizure discharge to adjacent
cortical structures.
Salanova V, et al. Brain 1992.
Williamsonj PD et al. Annals of Neurology 1992.

24. Other Neurological impairments.
Impairments Comments
Decreased visual acuity Related to severity of parieto-occpital injury.
All patients need formal testing for VA and
VF. Homonymous hemianopia and
quadrantanopia are the common deficits.
Deficits may be bilateral. Assessing mentally
subnormal children can be challenging.
Visual field defects
Strabismus, Nystagmus Common.
Cognitive deficits,
ADHD, Learning
disabilty.
Common, needs formal testing. Visuo-spatial
and executive dysfunction is reported.
Developmental delay Indicates severity of hypoxic insult.
Motor deficits
Uncommon, reflects a greater extent and
severity of damage.

25. Neonatal hypoglycemiaNeonatal hypoglycemia
 In a series of 6 patients with neonatal hypoglycemia
and symptomatic occipital lobe epilepsy:
 Median onset age of epilepsy: 2 years 8 months.
 Median follow-up: 12 years and 4 months.
 Seizure types: GTCS (4 pts), infantile spasm (1 pt),
CPS, SPS (6 pts), status epilepticus (6 pts).
 Seizure frequency: maximum during infancy and early
childhood and decreased thereafter.
Montassir H, et al.Epilepsy Research (2010)

26. Evaluation

27. Evaluation
 EEG and VEEG.
 MRI brain (1.5/ 3T)- epilepsy protocol.
 Visual field and acuity testing.
 Neuropsychological testing.
 Language assessment: fMRI, WADA.
 PET, SPECT.
 Invasive intracranial recording, SEEG.

28. Inter-ictal EEG of Patient P shows right PHR, mainly occipital, rhythmic spike
and wave discharges. Background is slow.

29. Inter-ictal EEG of Patient P shows right PHR, mainly occipital, rhythmic spike
and wave discharges. Spikes may be seen over radiologically normal areas.

30. Inter-ictal EEG of 10 year old male with bilateral PHR spikes and diffuse
slowing. He had infantile spasms initially, evolving later to CPS.

31. Right > left independent PHR spikes are noted. May indicate bilateral
epileptogenesis. Semiology was Rt occipital. MRI showed Rt> Lt P-O gliosis.

32. Ictal EEG
 May be lateralising and/or localising.
 May be 'false lateralising' and/or 'false localising'
because of rapid contralateral and ipsilateral spread
respectively.
 May be 'non-localised or non-lateralised' thus wrongly
indicating that the patient is not a surgical candidate!!

33. Ictal EEG
 ‘Generalised’ fast rhythms may be seen in patients
with tonic seizures or bilateral spikes in patients with
atypical absences (secondary bilateral synchrony).
 But the generalised rhythms in these patients are
different from the 10-20 Hz GPFA of LGS; they are
usually faster and of lower amplitude (LAFA).

34. Bursts of generalized fast polyspikes (10–20 Hz), especially in sleep,
define the EEG of LGS.

35. Salanova V, et al. Brain 1992.

36. Semiology and EEG
Usui N et al. Epilepsia 49(12): 2008.

37. MRI Brain
 Affected areas can be small or widespread, depending
on the severity of the hypoxic- ischemic event.
 Parieto-occipital areas are usually the most affected.
 Unilateral or often bilateral (but asymmetric) atrophy.
 Presence of asymmetric bilateral cortical and
subcortical scars and white matter changes around the
frontal horns.

38. MRI Criteria for Ulegyria
 Poorly demarcated lesion.
 Atrophy of the cortex involving mainly the deep
portion of the convolution and sparing the apex.
 White matter hyperintensities on T2/ T2F.
 Ulegyria can be distinguished from polymicrogyria by
MRI features such as the presence of white matter
abnormalities and peculiar mushroom-shaped gyri.
Usui N et al. Epilepsia 49(12): 2008

39. Patient P:T 2F axial, showing asymmetric (Rt > Lt) cortical
atrophy, dilatation of occipital horn of lateral ventricle.

40. Patient P:T2F Axial, showing asymmetric (Rt > Lt) cortical
atrophy, white matter hyperintensities and right parietal ulegyria.

41. Patient P:T2 Coronal showing asymmetric (Rt > Lt) cortical
atrophy involving occipito-parietal regions.

42. Patient P:T2 Coronal showing asymmetric (Rt > Lt) cortical
atrophy, white matter hyperintensities and right parietal ulegyria.

43. Patient P:T2F Coronal showing asymmetric (Rt > Lt) cortical
atrophy, white matter hyperintensities and right parietal ulegyria.

44. Intracranial EEG
 To identify the eloquent cortex.
 To identify ictal onset zone when scalp EEG is non-
localising. Of 5/10 patients with ulegyria who
underwent IEEG, only one had IEDs and ictal onset
confined to the MRI lesion.
 When multifocal epileptogenesis is suspected. In one
patient, 2 seizure semiology, each with a different
onset zone was noted.
 Extensive or bilateral lesions.
Usui N et al. Epilepsia 49(12): 2008.

45. Treatment

46. Medical management
 Aims of medical treatment:Aims of medical treatment:
1.1. Control of clinical seizures.Control of clinical seizures.
2.2. Suppression of subclinical seizures.Suppression of subclinical seizures.
3.3. Suppression of IEDs over undamaged cortical areas.Suppression of IEDs over undamaged cortical areas.
 This is important for the cognitive development inThis is important for the cognitive development in
this group of patients in whom the amount of normalthis group of patients in whom the amount of normal
brain structure is reduced.brain structure is reduced.

47. Epilepsy SurgeryEpilepsy Surgery
 Indications:
1. Refractory epilepsy.
2. Single seizure semiology.
3. Unilateral seizure onset zone.
4. More than one seizure type, provided seizure onset
zone is unilateral and surgically amenable.
5. Clinical-Electrical- Radiological concordance.

48. Resection, lobectomy, multi-lobar
resection.
 The extent of resection is determined primarily by the
location and extent of MRI lesions, taking functional
cortical areas into account.
 In a series of patients with PCE and Ulegyria, MRI
lesion could be completely resected in 8/10 patients.
 Irritative zone and seizure onset zone could not be
completely resected in 4/5 patients who underwent
intracranial EEG.
Usui N et al. Epilepsia 49(12): 2008.

49. Black area: extent of
lesion.
Black plus hatched:
extent of surgical
resection.
Usui N et al. Epilepsia 49(12): 2008.

50. Black area: extent of lesion. Black plus hatched: extent of surgical
resection. In patients 7 and 9, a small amount of lesion remained.
Usui N et al. Epilepsia 49(12): 2008.

51. Post-op seizure outcome.
Usui N et al. Epilepsia 49(12): 2008.
3 out of 4 patients whose seizure onset zones were not
completely resected achieved class I outcome.

52. Post-op deficits
Usui N et al. Epilepsia 49(12): 2008.
Most patients adapt well to the visual deficit over time.
ND, nondominant; D, dominant; FIQ, full-scale intelligence quotient; VIQ,
verbal intelligence quotient; PIQ, performance intelligence quotient.

53. Predictors of surgical outcome
 Seizure freedom occurs in 25- 90% patients.
 Completeness of resection.
 Absence of spikes on post-op ECoG.
 Absence of post-op spikes beyond PHR.
 In those who fail surgery, 75-80% have seizure
recurrence within 6 months of surgery.
Jehi LE, et al. Epilepsia 2009.

54. Rakhade SN, et al. Nat Rev Neurol. 2009

55. Conclusion
 PCE due to ulegyria is a surgically remediable
epilepsy syndrome.
 Good surgical outcomes are noted despite the history
of perinatal insult, multiple seizure types, mental
subnormality and markedly abnormal EEGs.
 Bilateral lesions can be considered for surgery if the
lesions are unilateral-predominant and if there is
clinical-electrical-radiological concordance.

56. THANK YOU