Posterior cortical epilepsies


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Posterior cortical epilepsies

  2. 2. <ul><li>The ILAE Commission (1989) classifies focal epilepsies according to their topographical/anatomical origin as: </li></ul><ul><ul><li>Temporal lobe epilepsies </li></ul></ul><ul><ul><li>Frontal lobe epilepsies </li></ul></ul><ul><ul><li>Parietal lobe epilepsies </li></ul></ul><ul><ul><li>Occipital lobe epilepsies </li></ul></ul><ul><li>These epilepsies may be idiopathic, cryptogenic or symptomatic </li></ul>
  3. 3. <ul><li>frontal lobe seizures </li></ul><ul><li>prominent motor activity at onset </li></ul><ul><li>posturing, focal tonic activity, and elaborate Gestures </li></ul><ul><li>Unilateral or bilateral tonic limb posturing, and bicycling movements </li></ul><ul><li>Atonic seizures (the supplementary negative motor area) </li></ul><ul><li>Speech arrest is often profound when it occurs </li></ul><ul><li>vocalizations, barking and nonverbal vocalizations </li></ul><ul><li>often brief, lasting under 1 minute, and typically less than 30 seconds, with little to no postictal phase </li></ul><ul><li>higher frequency, </li></ul><ul><li>often have a nocturnal Predilection </li></ul><ul><li>more apt to secondarily Generalize </li></ul><ul><li>psychic symptoms- mood and affect changes </li></ul><ul><li>Olfactory hallucinations </li></ul><ul><li>temporal lobe sezures </li></ul><ul><li>amnesia of the event, </li></ul><ul><li>reactive automatisms, </li></ul><ul><li>duration of the seizure for longer than one minute, </li></ul><ul><li>prolonged postictal confusion </li></ul><ul><li>experiential phenomena that suggest temporal onset </li></ul><ul><li>In mesial temporal onset </li></ul><ul><li>Autonomic- nausea and a rising epigastric sensation </li></ul><ul><li>psychic phenomena- panic and fear </li></ul><ul><li>lateral temporal lobe onset </li></ul><ul><li>more pronounced psychic phenomena- the sense of being in a dreamy state </li></ul><ul><li>Visual perceptual changes -Visual illusions ,multimodal hallucinations </li></ul><ul><li>Vertigo </li></ul><ul><li>early clonic movements </li></ul>
  4. 6. <ul><li>Posterior cortex epilepsies (PCEs) encompass a group of epilepsies originating from the occipital, parietal, or occipital border of the temporal lobe, or from any combination of these regions </li></ul>
  5. 7. <ul><li>characteristic feature of posterior neocortical seizures is the tendency to have multiple spread patterns (Salanova et al 1992, Fogarasi et al 2003). </li></ul><ul><li>This can occur among different patients or among different seizures in the same patient </li></ul><ul><li>can present with stereotyped but very different-appearing clinical seizures depending on direction of seizure spread </li></ul><ul><li>individual patients can have seizures that are not stereotyped from one to another, strongly suggesting multifocality </li></ul>
  6. 8. seizure propagation pathways
  7. 9. Seizure spread from posterior cortex <ul><li>occipital focus to the ipsilateral temporal lobe through the inferior longitudinal fasciculus </li></ul><ul><li>Similar pathways </li></ul><ul><ul><li>between the occipital lobes and the supplementary motor area and the thalamus </li></ul></ul><ul><ul><li>Between the parietal sensory cortex and the frontal motor and supplementary motor areas </li></ul></ul>
  8. 10. <ul><li>Many of the disabling clinical manifestations resulted from ictal spread to adjacent cortical structures </li></ul><ul><li>29–88% of patients exhibited automatisms typical of temporal lobe epilepsy </li></ul><ul><li>38–47% had focal motor activity </li></ul>
  9. 11. <ul><li>seizure spread has been suggested to influence the outcome of treatment </li></ul><ul><li>favorable outcome when spread is to suprasylvian regions </li></ul><ul><li>less favorable outcome when spread is to limbic structures </li></ul>
  10. 12. Parietal lobe epilepsies
  11. 13. <ul><li>primary epileptic focus anywhere within the parietal lobe </li></ul><ul><li>The 1989 ILAE Commission classifies parietal lobe epilepsies among the  localisation-related epilepsies </li></ul><ul><li>Parietal lobe epilepsies have not yet been detailed in the new ILAE diagnostic scheme </li></ul>
  12. 14. <ul><li>Demographic Data </li></ul><ul><li>start at any age </li></ul><ul><li>Both sexes are equally affected </li></ul><ul><li>Age at onset is much later in patients with tumours </li></ul><ul><li>6% of all focal epilepsies in neurosurgical series </li></ul><ul><li>twice as common as occipital lobe seizures </li></ul>
  13. 15. Clinical Manifestations <ul><li>mainly  simple focal  without impairment of consciousness </li></ul><ul><li>in order of prevalence: </li></ul><ul><ul><li>somatosensory </li></ul></ul><ul><ul><li>somatic illusions (subjective disturbances of body image) </li></ul></ul><ul><ul><li>vertiginous </li></ul></ul><ul><ul><li>visual illusions or complex formed visual hallucinations </li></ul></ul><ul><ul><li>receptive or conductive linguistic disturbances </li></ul></ul>
  14. 16. <ul><li>Somatosensory Seizures </li></ul><ul><li>the most common type (around two-thirds of cases) </li></ul><ul><li>Positive phenomena </li></ul><ul><ul><li>tingling and a feeling of electricity, which may be confined or may spread in a Jacksonian manner </li></ul></ul><ul><ul><li>desire to move a body part or a sensation as if a part were being moved </li></ul></ul><ul><ul><li>Muscle tone may be lost </li></ul></ul>
  15. 17. <ul><li>The parts most frequently involved </li></ul><ul><ul><li>those with the largest cortical representation (e.g., the hand, arm, and face) </li></ul></ul><ul><li>facial sensory phenomena may occur bilaterally </li></ul><ul><li>intraabdominal sensation of sinking, or nausea </li></ul><ul><ul><li>inferior and lateral parietal lobe </li></ul></ul>
  16. 18. <ul><ul><li>Negative phenomena (Non dominant parietal) </li></ul></ul><ul><ul><li>numbness, a feeling that a body part is absent </li></ul></ul><ul><ul><li>a loss of awareness of a part or a half of the body (somatoagnosia) </li></ul></ul><ul><li>Parietal lobe visual phenomena </li></ul><ul><ul><li>Metamorphopsia with distortions, shortenings, and elongations </li></ul></ul><ul><li>Rarely, there may be pain </li></ul><ul><ul><li>superficial burning dysaesthesia, or a vague, very severe pain </li></ul></ul>
  17. 19. <ul><li>receptive or conductive language disturbances </li></ul><ul><ul><li>Dominant paretal </li></ul></ul><ul><li>Lateralised genital sensatons </li></ul><ul><ul><li>Paracentral lobule </li></ul></ul>
  18. 20. <ul><li>Quality </li></ul><ul><li>Tingling may be the most characteristic symptom (76% in one study) </li></ul><ul><li>Pain, sometimes excruciating, is experienced by 25% of patients </li></ul>
  19. 21. <ul><li>Static or Jacksonian march </li></ul><ul><li>bilateral spread is rare </li></ul><ul><li>Unilateral somatosensory seizures are usually contralateral to the epileptogenic zone </li></ul><ul><li>Seizures ipsilateral to the side of seizure origin are exceptional </li></ul>
  20. 22. <ul><li>Ictal sensations in the genital areas and the rectum, and orgasmic seizures are infrequent </li></ul><ul><li>sexual automatisms (i.e. fondling the genitals) occur only in the postictal phase </li></ul><ul><li>Objective Ictal Somatosensory Deficits </li></ul><ul><ul><li>two-point discrimination was impaired in the contralateral hand </li></ul></ul>
  21. 23. <ul><li>Disturbances of Body Image and Somatic Illusions (posterior parietal lobe) </li></ul><ul><li>second most common ictal symptom </li></ul><ul><li>Ictal  limb agnosia  ,phantom limb sensations </li></ul><ul><li>Neglect is more commonly associated with the right rather than the left inferior parietal lobe </li></ul><ul><li>Illusions of movement </li></ul>
  22. 24. <ul><li>Vertigo ( temporo-parietal border) </li></ul><ul><ul><li>about 10% as ictal manifestations </li></ul></ul><ul><li>Visual illusions and complex formed visual hallucinations (non-dominant parietal regions) </li></ul><ul><ul><li>about 12% of patients </li></ul></ul>
  23. 25. <ul><li>Linguistic Disturbances (dominant temporal-parietal lobe) </li></ul><ul><ul><li>alexia with agraphia and significant calculation defects </li></ul></ul><ul><li>Inhibitory motor seizures, ictal hemiplegia or negative motor manifestations,drop attacks </li></ul><ul><ul><li>exceptional </li></ul></ul>
  24. 26. Seizure spread <ul><li>Posterior propagation - elementary visual hallucinations or ictal amaurosis (Williamson 1987). </li></ul><ul><li>Anterior spread can produce focal clonic motor activity. </li></ul><ul><li>spread to the supplementary motor area- asymmetrical tonic motor activity (Siegel et al 1999). </li></ul><ul><li>Inhibitory or hemiplegic seizures may occur, but it is not known whether this represents spread beyond the parietal lobe </li></ul>
  25. 27. <ul><li>posterior parietal lobe seizure spread to the temporal lobes, produce &quot;psychoparetic&quot; seizures (Ho et al 1994). </li></ul><ul><li>Parietal lobe seizures resembling panic attacks -reflect temporal lobe seizure spread ( Sazgar et al 2003). </li></ul><ul><li>When seizures arise in “silent” areas of the parietal lobe and propagate anteriorly, they can be confused with frontal lobe seizures. </li></ul>
  26. 28. <ul><li>Frequency of seizure Spreading to Extraparietal Regions </li></ul><ul><ul><li>unilateral focal clonic convulsions (57% of patients), </li></ul></ul><ul><ul><li>head and eye deviation (41% of patients), </li></ul></ul><ul><ul><li>tonic posturing of usually one extremity (28% of patients) </li></ul></ul><ul><ul><li>automatisms (21% of patients) </li></ul></ul><ul><ul><li>Secondary GTCS are usually infrequent </li></ul></ul>
  27. 29. <ul><li>Duration of Seizures </li></ul><ul><ul><li>few seconds to 1–2 min </li></ul></ul><ul><ul><li>Prolonged isolated sensory auras </li></ul></ul><ul><li>Postictal Manifestations </li></ul><ul><ul><li>usually short </li></ul></ul><ul><ul><li>Todd’s paralysis (22%) </li></ul></ul><ul><ul><li>dysphasia (7%) </li></ul></ul>
  28. 30. <ul><li>Epileptogenic Localisation </li></ul><ul><li>primary sensory cortex </li></ul><ul><ul><li>contralateral positive or negative symptoms </li></ul></ul><ul><ul><li>also occur with seizures emanating from posterior parietal regions </li></ul></ul><ul><li>secondary sensory area </li></ul><ul><ul><li>Bilateral sensory symptoms </li></ul></ul><ul><li>parietal paracentral lobule </li></ul><ul><ul><li>Ictal sensations in the genital areas </li></ul></ul><ul><li>area 5a </li></ul><ul><ul><li>Ictal pain </li></ul></ul>
  29. 31. <ul><li>Precipitating Factors </li></ul><ul><li>movements of the affected part of the body, tapping or other somatosensory stimuli </li></ul><ul><li>Sensorimotor seizures may also be triggered by music or toothbrushing </li></ul>
  30. 32. <ul><li>Aetiology </li></ul><ul><li>Non tumoural patients with parietal lobe epilepsy </li></ul><ul><ul><li>Out of 82 patients Salanova V reported </li></ul></ul><ul><ul><li>43% had a history of head trauma </li></ul></ul><ul><ul><li>16% a history of birth trauma </li></ul></ul><ul><ul><li>the cause was unknown in 20% </li></ul></ul>
  31. 33. <ul><li>The remaining 21% </li></ul><ul><ul><li>history of encephalitis </li></ul></ul><ul><ul><li>febrile convulsions </li></ul></ul><ul><ul><li>gunshot wounds to the head </li></ul></ul><ul><ul><li>forme fruste of tuberous sclerosis </li></ul></ul><ul><ul><li>hamartoma </li></ul></ul><ul><ul><li>vascular malformations </li></ul></ul><ul><ul><li>tuberculoma </li></ul></ul><ul><ul><li>arachnoid or porencephalic cysts </li></ul></ul><ul><ul><li>microgyria </li></ul></ul><ul><ul><li>post-traumatic thrombosis of the middle cerebral artery </li></ul></ul>
  32. 34. <ul><li>tumours </li></ul><ul><ul><li>astrocytomas (62%) </li></ul></ul><ul><ul><li>meningiomas (14%) </li></ul></ul><ul><ul><li>hemangiomas (9%) </li></ul></ul><ul><ul><li>oligodendrogliomas (9%) </li></ul></ul><ul><ul><li>ependymoblastomas (3%). </li></ul></ul>
  33. 35. <ul><li>In reports with MRI, malformations of cortical development - the most common cause </li></ul>
  34. 36. <ul><li>Diagnostic Procedures </li></ul><ul><li>Neurological examination usually normal </li></ul><ul><ul><li>impaired two-point discrimination or stereoagnosia </li></ul></ul><ul><ul><li>mild limb atrophy </li></ul></ul><ul><ul><li>inferior quadrantic visual field defects </li></ul></ul><ul><ul><li>disturbances of written language, aphasia, spatial orientation and right-left disorientation </li></ul></ul><ul><li>tumoural parietal lobe epilepsy </li></ul><ul><ul><li>mild contralateral weakness is common (38%) </li></ul></ul><ul><ul><li>unilateral limb atrophy is exceptional </li></ul></ul>
  35. 37. <ul><li>Brain imaging </li></ul><ul><li>High resolution MRI </li></ul><ul><ul><li>abnormal in 60% </li></ul></ul><ul><li>FDG-PET and ictal SPECT </li></ul><ul><ul><li>are useful in presurgical evaluations </li></ul></ul>
  36. 38. <ul><li>Electroencephalography </li></ul><ul><li>Interictal EEG </li></ul><ul><ul><li>may be normal, non-specific, or even misleading </li></ul></ul><ul><ul><li>In symptomatic patients- localised slow waves </li></ul></ul><ul><li>False localising to frontal, temporal or occipital electrodes </li></ul><ul><li>16% do not have epileptiform discharges </li></ul><ul><li>secondary bilateral synchrony is common (32%) </li></ul>
  37. 39. <ul><li>Ictal EEG </li></ul><ul><li>The ictal EEG may be normal in 80% of simple focal sensory seizures </li></ul><ul><li>The prevalence of scalp EEG changes </li></ul><ul><ul><li>sensory seizures- 15% </li></ul></ul><ul><ul><li>as opposed to 33% when motor symptoms are present </li></ul></ul><ul><li>Postictal EEG </li></ul><ul><ul><li>focal slow wave, attenuation of background activity or spikes </li></ul></ul>
  38. 46. <ul><li>Differential Diagnosis </li></ul><ul><li>Somatosensory seizures are misdiagnosed as </li></ul><ul><ul><li>non-epileptic psychogenic fits > transient ischaemic attacks > migraine with aura </li></ul></ul>
  39. 47. <ul><li>Management </li></ul><ul><li>Drug treatment is similar to focal seizures and is usually effective </li></ul><ul><li>In intractable cases, neurosurgery achieves seizure-free state or remarkable improvement (> 65%) </li></ul>
  40. 48. <ul><li>Better prognostic factors </li></ul><ul><ul><li>MRI abnormality </li></ul></ul><ul><ul><li>concordance of different diagnostic modalities </li></ul></ul><ul><ul><li>completeness of resection of the epileptogenic zone </li></ul></ul><ul><li>Resection may be problematic </li></ul><ul><ul><li>deficits in vision ,language, praxis, attention and higher cortical function </li></ul></ul>
  41. 49. Occipital Lobe Epilepsies
  42. 50. <ul><li>Occipital seizures originate from an epileptic occipital focus </li></ul><ul><li>triggered spontaneously or by external visual stimuli </li></ul><ul><li>idiopathic, symptomatic or probably symptomatic </li></ul>
  43. 51. <ul><li>Demographic Data </li></ul><ul><li>Occurs at any age </li></ul><ul><li>5–10% of all epilepsies </li></ul><ul><li>5% in neurosurgical series </li></ul><ul><li>6% seen in demographic studies </li></ul>
  44. 52. Clinical Manifestations <ul><li>The cardinal symptoms are mainly visual and oculomotor </li></ul><ul><li>Visual subjective symptoms </li></ul><ul><ul><li>elementary and less often complex visual hallucinations </li></ul></ul><ul><ul><li>blindness </li></ul></ul><ul><ul><li>visual illusions </li></ul></ul><ul><ul><li>pallinopsia </li></ul></ul><ul><ul><li>sensory hallucinations of ocular movements </li></ul></ul><ul><ul><li>ocular pain. </li></ul></ul>
  45. 53. <ul><li>Ictal objective oculomotor symptoms </li></ul><ul><ul><li>tonic deviation of the eyes (pursuit-like rather than oculotonic) </li></ul></ul><ul><ul><li>oculoclonic movements or nystagmus </li></ul></ul><ul><ul><li>repetitive eyelid closures or eyelid fluttering </li></ul></ul>
  46. 54. <ul><li>elementary visual hallucinations </li></ul><ul><ul><li>the primary visual cortex </li></ul></ul><ul><li>visual illusions </li></ul><ul><ul><li>the occipital-parietal and occipito-temporal junctions </li></ul></ul><ul><li>Seizures may spread from the occipital to anterior regions </li></ul><ul><ul><li>generate symptoms from the temporal, parietal and frontal lobes </li></ul></ul><ul><ul><li>secondarily hemi- or generalised convulsions </li></ul></ul><ul><li>Ictal or postictal headache is frequent </li></ul>
  47. 55. Elementary Visual Hallucinations <ul><li>the most common, characteristic and well-defined ictal symptoms </li></ul><ul><li>Often the first symptom </li></ul><ul><li>may progress to other occipital and extra-occipital manifestations and convulsions </li></ul>
  48. 56. <ul><li>mainly coloured and circular </li></ul><ul><li>develop rapidly within seconds and are brief in duration </li></ul><ul><li>often appear in the periphery of a temporal visual hemifield </li></ul><ul><li>become larger and multiply in the course of the seizure, </li></ul><ul><li>frequently move horizontally towards the other side </li></ul>
  49. 57. <ul><li>Colour, Shape and Size </li></ul><ul><ul><li>usually multicoloured </li></ul></ul><ul><ul><li>Shapes are mainly circular, spots, circles and balls </li></ul></ul><ul><ul><li>square, triangular and rectangular - less frequent </li></ul></ul><ul><ul><li>increase in number, size or both with progression of the seizure </li></ul></ul>
  50. 58. <ul><li>Location </li></ul><ul><ul><li>usually unilateral </li></ul></ul><ul><ul><li>temporal visual hemifield </li></ul></ul><ul><ul><li>may appear in a normal, blind or damaged hemifield </li></ul></ul><ul><ul><li>Central or undefined localisation occurs in 10–30% of patients </li></ul></ul>
  51. 59. <ul><li>Lateralisation </li></ul><ul><ul><li>contralateral  to the epileptogenic focus </li></ul></ul><ul><ul><li>Conversely, this is  ipsilateral  to the epileptogenic focus for unilateral visual hallucinations moving horizontally towards the other side </li></ul></ul>
  52. 60. <ul><li>Vision </li></ul><ul><ul><li>obscured only in the area occupied by the visual hallucinations </li></ul></ul><ul><ul><li>some patients able to read through them </li></ul></ul><ul><ul><li>Blurring of vision at onset may be a form of visual seizure </li></ul></ul>
  53. 61. <ul><li>Duration </li></ul><ul><ul><li>develop rapidly within seconds </li></ul></ul><ul><ul><li>usually brief, lasting from a few seconds to 1–3 min </li></ul></ul><ul><ul><li>Exceptionally, they last for 20–150 minutes- focal visual status epilepticus </li></ul></ul><ul><ul><li>As a rule, last longer prior to secondarily generalisation </li></ul></ul>
  54. 62. <ul><li>Frequency and Circadian Distribution </li></ul><ul><ul><li>often in multiple clusters, daily or weekly </li></ul></ul><ul><ul><li>usually diurnal </li></ul></ul><ul><ul><li>Rarely on awakening </li></ul></ul><ul><li>Stereotypic Appearance </li></ul><ul><ul><li>stereotyped, particularly at onset, in all aspects other than duration </li></ul></ul><ul><ul><li>same patient experiencing different types of seizures is exceptional </li></ul></ul>
  55. 63. <ul><li>Progression to Other Occipital or Non-Occipital Seizure Manifestations </li></ul><ul><li>often progress to other ictal symptoms </li></ul><ul><ul><li>complex visual hallucinations </li></ul></ul><ul><ul><li>oculoclonic seizures </li></ul></ul><ul><ul><li>tonic deviation of the eyes </li></ul></ul><ul><ul><li>eyelid fluttering or repetitive eye closures </li></ul></ul><ul><ul><li>impairment of consciousness </li></ul></ul><ul><ul><li>experiential phenomena </li></ul></ul><ul><ul><li>hemi-anaesthesia </li></ul></ul><ul><ul><li>unilateral or generalised convulsions </li></ul></ul><ul><li>extra-occipital seizure manifestations by spread to the temporal, frontal or parietal regions. </li></ul>
  56. 65. <ul><li>Complex Visual Hallucinations, Visual Illusions and Other Symptoms from More Anterior Ictal Spreading </li></ul><ul><li>Complex visual hallucinations  </li></ul><ul><ul><li>persons, animals, objects, figures or scenes </li></ul></ul><ul><ul><li>familiar or unfamiliar, friendly or frightening </li></ul></ul><ul><ul><li>small or large area of a hemifield, or in the centre and the whole of the visual field </li></ul></ul><ul><ul><li>static, move horizontally, expand or shrink, approach or move away </li></ul></ul><ul><ul><li>do not have the emotional character of temporal lobe seizures </li></ul></ul><ul><ul><li>complex visual hallucinations may appear in the defective visual field </li></ul></ul>
  57. 66. <ul><li>Ictal autoscopia </li></ul><ul><ul><li>originate from occipito-parietal and occipito-temporal junction areas </li></ul></ul><ul><li>Visual illusions  </li></ul><ul><ul><li>Metamorphopsia,micropsia or macropsia,achromatopsia,monochromopsia </li></ul></ul><ul><li>Palinopsia </li></ul><ul><ul><li>persistence or recurrence of visual images </li></ul></ul><ul><ul><li>with right posterior parieto-temporal lesions. </li></ul></ul>
  58. 67. <ul><li>Sensory Hallucinations of Ocular Movements </li></ul><ul><ul><li>sensation of ocular movement in the absence of detectable motion - rare </li></ul></ul><ul><li>Ictal Blindness </li></ul><ul><ul><li>often occurs as a starting or the only ictal seizure manifestation with abrupt onset </li></ul></ul><ul><ul><li>may follow the visual hallucinations </li></ul></ul><ul><ul><li>may last for hours or days  (status epilepticus amauroticus) . </li></ul></ul><ul><ul><li>one-third of patients with symptomatic and two-thirds of patients with idiopathic occipital epilepsy </li></ul></ul>
  59. 68. <ul><li>Tonic Deviation of the Eyes, Oculoclonic Seizures and Epileptic Nystagmus </li></ul><ul><ul><li>Tonic deviation of the eyes  often, followed by ipsilateral turning of the head (40–50% of cases) – The most common non visual symptom </li></ul></ul><ul><ul><li>Consciousness is often impaired when eye deviation occurs </li></ul></ul><ul><ul><li>The epileptogenic focus is contralateral if consciousness is not impaired </li></ul></ul>
  60. 69. <ul><li>Ictal nystagmus </li></ul><ul><ul><li>quick phase of the nystagmus is opposite to the epileptic focus </li></ul></ul><ul><ul><li>in the same direction of eye and head deviation </li></ul></ul><ul><li>Repetitive eyelid closures, eyelid fluttering and eyelid blinking  </li></ul><ul><ul><li>heralds the impending secondary GTCS </li></ul></ul><ul><li>Eyelid opening, or ‘eyes widely opened’ </li></ul><ul><ul><li>well-described symptom in occipital epilepsy </li></ul></ul><ul><ul><li>typical symptom of mesial temporal lobe seizures </li></ul></ul>
  61. 70. <ul><li>Consciousness </li></ul><ul><li>Not impaired during hallucinations </li></ul><ul><li>may be disturbed or lost at the time of eye deviation or eye closure </li></ul><ul><li>Ictal or Postictal Headache </li></ul><ul><li>frequently associated - 50% of cases </li></ul><ul><li>mainly orbital </li></ul><ul><li>often indistinguishable from migraine </li></ul><ul><li>postictal headache often occurs 3–15 min from the end of the visual seizure, (  ‘asymptomatic interval’) </li></ul>
  62. 71. Seizure Spread <ul><li>Infra-calcarine occipital foci </li></ul><ul><ul><li>will propagate to the temporal lobe causing complex focal seizures </li></ul></ul><ul><li>supra-calcarine foci </li></ul><ul><ul><li>tend to propagate to the parietal and frontal areas giving rise to predominantly motor seizures. </li></ul></ul>
  63. 73. Aetiology <ul><li>Idiopathic, structural or metabolic </li></ul><ul><li>Malformations of cortical development are a common cause </li></ul><ul><li>Metabolic or other derangements, such as eclampsia, may have a particular predilection for the occipital lobes </li></ul><ul><li>Occipital seizures may be the first manifestation of celiac disease,Lafora disease or mitochondrial disorders </li></ul>
  64. 76. Pathophysiology <ul><li>Elementary visual hallucinations </li></ul><ul><ul><li>primary visual cortex </li></ul></ul><ul><li>complex visual hallucinations </li></ul><ul><ul><li>occipito-parietal-temporal junction areas </li></ul></ul><ul><li>visual illusions </li></ul><ul><ul><li>non-dominant parietal regions </li></ul></ul><ul><li>Ictal blindness </li></ul><ul><ul><li>contralateral seizure spread to involve both occipital lobes or to inhibition of the visual cortex by the seizure discharge </li></ul></ul>
  65. 77. <ul><li>postictal headache </li></ul><ul><ul><li>occipital lobes are preferentially associated with the trigeminovascular or brainstem mechanisms responsible for headache </li></ul></ul><ul><ul><li>related to serotonergic mechanisms and respond to oral sumatriptan </li></ul></ul><ul><ul><li>Another similarity with migraine - asymptomatic interval’   </li></ul></ul>
  66. 78. <ul><li>Diagnostic Procedures </li></ul><ul><li>symptomatic occipital epilepsies </li></ul><ul><ul><li>haematology and biochemistry screening for metabolic disorders, molecular DNA analysis, or even skin or other tissue biopsy </li></ul></ul><ul><ul><li>  High resolution MRI </li></ul></ul><ul><ul><li>calcifications of CD – CT scan </li></ul></ul><ul><ul><li>f-MRI- practical value in neurosurgical cases. </li></ul></ul>
  67. 79. Electroencephalography <ul><li>Interictal EEG </li></ul><ul><li>In symptomatic cases </li></ul><ul><ul><li>Background EEG is usually abnormal with posterior lateralised slow waves </li></ul></ul><ul><ul><li>Unilateral occipital spikes or fast multiple spikes and, occasionally, occipital paroxysms occur </li></ul></ul><ul><ul><li>There may be occipital photosensitivity </li></ul></ul>
  68. 81. <ul><li>In idiopathic cases </li></ul><ul><ul><li>the background interictal EEG is normal Eg:Gastaut-type idiopathic childhood occipital epilepsy and photosensitive occipital epilepsy </li></ul></ul><ul><ul><li>Occipital spikes and occipital paroxysms, spontaneous, evoked or both, are often abundant </li></ul></ul><ul><ul><li>disappear with age </li></ul></ul>
  69. 82. <ul><li>Ictal EEG </li></ul><ul><li>paroxysmal fast activity, fast spiking or both, localised in the occipital regions </li></ul><ul><li>occasional gradual anterior spreading and generalisation with irregular spike wave discharges or monomorphic spike and wave activity </li></ul><ul><li>Brief occipital flattening may be seen before the fast rhythmic pattern. </li></ul>
  70. 88. <ul><li>symptomatic occipital lobe epilepsy </li></ul><ul><ul><li>the ictal discharge is more widespread </li></ul></ul><ul><ul><li>postictal localised slowing when the seizure is prolonged or progresses to secondarily GTCS </li></ul></ul><ul><li>30% of the ictal surface EEG -  normal in occipital seizures </li></ul>
  71. 89. <ul><li>Differential Diagnosis </li></ul><ul><li>should be first differentiated from </li></ul><ul><ul><li>migraine </li></ul></ul><ul><ul><li>normal phenomena </li></ul></ul><ul><ul><li>Psychogenic </li></ul></ul>
  72. 90. Occipital seizure Migrane with aura Basilar migrane Occipital epilepsy Migraine with aura Basilar migraine Visual hallucinations Duration for seconds to a minute Exclusive None None Duration for 1–3 minutes Frequent Rare Rare Duration for 4–30 minutes Rare As a rule As a rule Daily in frequency As a rule Rare None Mainly coloured circular patterns As a rule Rare Exceptional Mainly achromatic or black and white linear patterns Exceptional As a rule Rare Moving to the opposite side of the visual field Exclusive None None Expanding from the centre to the periphery of a visual hemifield Rare As a rule Frequent Evolving to blindness Rare Rare As a rule Evolving to tonic deviation of eyes Exclusive None None Evolving to impairment of consciousness without convulsions Frequent Rare Frequent Evolving to impairment of consciousness with convulsions Frequent Exceptional Rare Associated with post-ictal/post-critical headache Frequent As a rule Frequent Blindness and hemianopia Without other preceding or following symptoms Frequent None Frequent Other neurological symptoms Brain stem symptoms None None Exclusive Post-ictal/post-critical vomiting Rare Frequent Frequent Post-ictal/post-critical headache Post-ictal or post-critical severe headache Frequent As a rule Frequent
  73. 91. <ul><li>Differentiating Idiopathic from Symptomatic Occipital Epilepsy </li></ul><ul><li>symptomatic visual seizures </li></ul><ul><ul><li>progress to other extra-occipital seizure manifestations and mainly temporal lobe seizures </li></ul></ul><ul><ul><li>temporal lobe symptoms are nearly exclusive </li></ul></ul><ul><li>High resolution MRI </li></ul>
  74. 92. Prognosis <ul><li>good to intractable or progressive </li></ul><ul><li>depends on the underlying cause and extent of the lesions </li></ul>
  75. 93. Management <ul><li>AED treatment is similar to that for any other type for focal seizures </li></ul><ul><li>usually effective </li></ul><ul><li>Should be initiated as soon as possible </li></ul><ul><li>Carbamazepine is the drug of choice </li></ul><ul><li>postictal headache - oral sumatriptan </li></ul><ul><li>Neurosurgery is effective in around 70% of patients with 30% becoming seizure free </li></ul>
  76. 94. The Drug Treatment of Focal Epilepsies <ul><li>In head-to-head comparisons among old AEDs </li></ul><ul><ul><li>overall treatment success was highest with carbamazepine or phenytoin </li></ul></ul><ul><ul><li>intermediate with phenobarbitone </li></ul></ul><ul><ul><li>lowest with primidone </li></ul></ul>
  77. 95. <ul><li>carbamazepine vs valproate </li></ul><ul><ul><li>carbamazepine provided better control of complex focal seizures </li></ul></ul><ul><ul><li>CBZ had fewer long-term adverse effects than valproate </li></ul></ul><ul><ul><li>Both drugs were comparably effective for the control of secondarily GTCS </li></ul></ul>
  78. 96. <ul><li>The new AEDs </li></ul><ul><ul><li>gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, vigabatrin and zonisamide </li></ul></ul><ul><ul><li>nearly equal efficacy to carbamazepine, phenytoin and valproate </li></ul></ul>
  79. 97. Efficacy Tolerability Serious adverse events Drug–drug interaction Pharmacokinetics Titration Need for laboratory testing Mechanism of action Levetiracetam High Excellent no no Ideal Fast minimal Novel SV2A - ligand Lamotrigine Low Excellent yes yes Poor Very slow maximal Na+ Topiramate High Poor yes yes Satisfactory Very slow Maximal multiple Oxcarbazepine Medium poor yes yes Poor Slow Maximal Na+ Zonisamide Medium good yes no satisfactory slow maximal multiple
  80. 98. Surgical treatment
  81. 99. <ul><li>Rasmussen (1975),first reported good outcome after removal of nontumoral epileptogenic lesions in 86 parietal cases and 25 occipital cases </li></ul><ul><li>Removal of a temporal lobe has also been reported to provide favorable results in some patients in whom the dominant seizure symptomatology was a result of spread of seizure discharge to that temporal lobe </li></ul>
  82. 100. <ul><li>Occipital epilepsy is often associated with a large epileptogenic zone </li></ul><ul><li>complete resections difficult </li></ul><ul><li>more extensive resections are a key to improved seizure control </li></ul><ul><li>In functionally critical areas such as the primary sensory cortex, multiple subpial transsections of the epileptogenic areas have been reported to be successful </li></ul>
  83. 103. ------------
  84. 104. Clinical Features of Patients with Posterior Cortex Epilepsies and Predictors of Surgical Outcome <ul><li>Charles L. Dalmagro et al </li></ul><ul><li>epilepsia, , 2005 </li></ul><ul><li>Department of Neurology, Federal University of Santa Catarina, Brazil </li></ul><ul><li>Surgical treatment was highly effective (p < 0.001) when compared with previous pharmacologic treatment alone. </li></ul><ul><li>28/44 (65.11%) patients became seizure free </li></ul>
  85. 105. Posterior cortex epilepsy: Diagnostic considerations and surgical outcome <ul><li>Tao Yu et al </li></ul><ul><li>Seizure (2009), </li></ul><ul><li>Beijing Institute of Functional Neurosurgery, China </li></ul><ul><li>Thirty-one (72.1%) had favorable surgical outcome (Engel class I and II) </li></ul><ul><li>26 (60.5%) seizure free patients </li></ul>
  86. 106. Cognitive changes after epilepsy surgery in the posterior cortex (R Luerding) <ul><li>J Neurol Neurosurg Psychiatry 2004 </li></ul><ul><li>Epilepsy surgery in the posterior cortex bears no risk for substantial decline in general cognition </li></ul><ul><li>some discrete impairment in performance intelligence may occur </li></ul>
  87. 107. Thank you