Inter Ictal Epileptiform discharges and ictal pattern TLE.pptx
- 1. Interictal and Ictal EEG in Temporal Lobe Epilepsy Dr. Atma Ram Bansal (MD,DM) Certified fellow in Epilepsy (SCTIMST) Certified Electroencephalographer (Asian epilepsy Academy) Sr Consultant Neurology & Epilepsy Medanta Institute of Neuroscience Medanta-The Medicity, Gurgaon
- 2. Semiology Lateralization & Localization Lateralization Hemispherical Right hemisphere Left hemisphere Dominant Nondominant Localization Lobar Temporal Extratemporal Frontal, Parietal, Occipital Sublobar Mesial & lateral TLE Predictive (localization) value of semiology: ~80%
- 3. Types of Temp Lobe Epilepsy Mesial (MTLE) and lateral (neocortical) temporal epilepsy (NTE) Mesial temporal epilepsy is the best known and the most frequent (Bercovici et al., 2012; Tatum, 2012). mTLE-HS is the most common form of focal epilepsy
- 6. Commonest surgically remediable syndrome Common substrates: MTS (HS) Dysplatic lesions: DNET, GG Dysplasia Mesial Temporal Lobe Epilepsy
- 7. Neocortical Temp Lobe Epilepsy Post encephalitic sequele Gliosis- post traumatic Low grade tumours Cavernous Malformation Herniation of temp lobe
- 8. Temporal Vs Extratemporal Slow evolution Hypomotor Motionless stare Complex automatisms: Oroalimetary Unilateral dystonic limb posturing Contralateral limb automatisms Duration > 1 min. Infrequent sec. generalization Rapid evolution Hypermotor Vocalization Prominent motor activity: Primary motor Urinary incontinence Frantic behavior Brief (<1 min) duration Frequent sec. generalization
- 9. Mesial and Neocortical TLE Clinical features Mesial Neocortical Frequency 90% 10% Risk factors FS, CNS infections, head trauma, perinatal injuries (common) Less frequent Age at onset Adolescence or young adults Five to ten years later than MTS Type of aura Abdominal, olfactory, gustatory, dreamy state and fear feelings Psychic, auditory hallucination, vertigo, visual symptoms, cephalic sensation, nonspecific auras Staring and Late Early
- 10. Mesial and Neocortical TLE Clinical features Mesial Neocortical Automatisms Early, in the first 20 seconds, oral and manual automatism, frequent searching Late or absent. Searching less frequent Motor Ipsilateral automatisms followed by con- tralateral dystonic posturing. Leg move- ments and body shifting more likely Early contralateral dystonic posturing. Clonic movements more likely, leg movements less likely Secondary
- 11. B G Ci n Stria Th Forni x Hippocampus Arrest Insula/amygdala Epigastric aura, salivation Operculam Oro- alimentary automatisms SMA ATLP Primary motor area Clonic jerks Basal ganglia Limb dystonia
- 12. Interictal Discharges Mesial Temporal vs Neocortical Discharges in relation to pathology Javidan , Epilepsy Res Treat. 2012; 2012: 637430.
- 13. Historical Aspects Psychomotor variant by Gibbs et al. in 1935 Lewis recorded EEG in patients with behavioural disorders and epilepsy. Epileptogenic foci based on ictal and interictal Predict the location of the lesion within 2-3 cm in 85% of patients Bailey and Gibbs in 1951 resected the ATL mainly based on the EEG evidence.
- 14. Interictal Discharges Focal Slowing- TIPDA Rhythmic Slowing-TIRDA Upto 90% of patients with MRI evidence of hippocampal atrophy and mTLE Focal discharges F7, F8, T1, T2, and sphenoidal electrodes in Mtle T3,T4,T5,T6 in nTLE Rhythmic discharges
- 15. Unilateral vs Bilateral Strictly unilateral discharges more specific Correlate with the side of the seizure origin in 94% of patients More common in awake and REM ~one-third of patients with mTLE have bitemporal independent spikes or sharp waves Mostly during non-REM sleep
- 16. Type 1 Vs Type 2 Spike Type 1- More in mesial temporal Negative fields sharply defined, Steep voltage gradients, are located inferolaterally Distinct, contralateral positive fields Positive maxima exclusively located in opposite hemisphere opposite Usually occupied a parieto- or frontocentral position.
- 17. Type 2 spike Broad negative fields that extend to or beyond the midline, gradual voltage gradient Less clear or no associated positive field Against mesial temporal origin
- 22. Type II
- 26. Interictal
- 27. Oligospikers: 10% Restricted epileptogenic zone Good surgical outcome TIPDA: Common; Nonspecific; ET epilepsies also
- 28. TIRDA TIRDA: 30-60% cases Specific for TLE
- 29. B/L temporal IEDs: 40-50%
- 30. IEDs differ from MTLE: Morphology Broad sharp waves; wide fields Sharp spikes Location Mid and posterior temporal; Central Polymorphic slowing more common ET IEDs more common IEDs in LTLE
- 31. IEDs differ from MTLE: Morphology Broad sharp waves; wide fields Sharp spikes Location Mid and posterior temporal; Central Polymorphic slowing more common ET IEDs more common IEDs in LTLE
- 32. RSD: Dysplasia
- 33. No IEDs: 10-15% B/L IEDs: 40-50% ET IEDs: 5-10% Diffuse injuries Doesnt preclude good outcome Nonspecific: Temporal IEDs are common in ET epilepsies Should be evaluated with other data Rathore et al., Epilespia, 2009 IEDs in MTLE: Pitfalls
- 34. Orbitofrontal lesions: Temporal IEDs
- 35. Ictal patterns in TLE Typical ictal patterns for TLE Different for mesial and neocortical TLE
- 37. Right MTLE-HS
- 38. Left MTLE -HS
- 42. Ictal propogation Monomorphic Sharp Theta Activity
- 45. Type 1A: Monomorphic, 5-7 Hz, stable theta rhythm Typical for hippocampal seizures Less common: 25% Propogation through inferolateral temporal neocortex Postictal slowing
- 46. Ictal onset
- 49. Ictal onset: LSP; Late lateralization
- 52. LSP: Late sustained pattern
- 53. Temporal neocortical epilepsy Ictal patterns Differ from MTLE Slow, unstable, changing rhythms Fast rhythms
- 54. Patient 1 Rt. Temporal neocortical epilepsy
- 57. Left NTLE
- 60. Onset Temporal dysplasia LVFA: Left temporal dysplasia
- 63. Thanks