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Clinical Epilepsy: Syndromes, Causes, and Effects

Clinical Epilepsy: Syndromes, Causes, and Effects. Russell M. Bauer, Ph.D. Department of Clinical & Health Psychology. Definition: the clinical manifestation of an abnormal and excessive excitation of a population of cortical neurons Incidence: approximately 80/100,000 per year

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Clinical Epilepsy: Syndromes, Causes, and Effects

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  1. Clinical Epilepsy: Syndromes, Causes, and Effects Russell M. Bauer, Ph.D. Department of Clinical & Health Psychology

  2. Definition: the clinical manifestation of an abnormal and excessive excitation of a population of cortical neurons Incidence: approximately 80/100,000 per year Lifetime prevalence: 9% (1/3 benign febrile convulsions) Seizures vs Epilepsy Seizures Epilepsy • Definition: a tendency toward recurrent seizures unprovoked by systemic or neurologic insults • Incidence: approximately 45/100,000 per year Approximately 181,000 people will experience seizures or develop epilepsy each year • Point prevalence: 0.5-1% (2.5 million) • 14 years or younger 13% • 15 to 64 years 63% • 65 years and older 24% • Cumulative risk of epilepsy through 74 years old: 1.3% - 3.1%

  3. Partial (focal) Seizures • Simple Partial Seizure • no loss of awareness • Complex Partial Seizure • Impaired consciousness/ level of awareness (staring) • Clinical manifestations vary with origin & degree of spread • Presence and nature of aura • Temporal lobe: smell, epigastric sensation, deja vu • Automatisms (manual, oral) • Other motor activity Frontal: bicycling and fencing posture • Duration (typically 30 seconds to 3 minutes) • Amnesia for event • Partial Seizure with Secondary Generalization

  4. Localization of Partial Seizure Focus 20% 10% 70%

  5. Temporal Lobe Complex Partial Seizure Rhythmic 5-7 Hz theta from the mesial temporal lobe

  6. Primarily Generalized Seizures • Absence • Typical (3 Hz spike and wave) • Atypical (2.5 to 4.5 Hz spike and wave, polyspike) • Brief staring (<30sec); automatisms rare; not post-ictal confusion • Myoclonic • Brief, shock-like muscle contractions- Head- Upper extremities • Usually bilaterally symmetrical • Consciousness preserved • Precipitated by awakening or falling asleep • May progress into clonic or tonic-clonic seizure • May be associated with a progressive neurolgic deterioration • Juvenile Myoclonic Epilepsy (JME) • Polyspike wave • Onset late adolescence • Chromosome 6p • Progressive Myoclonic Epilepsies • Atonic/ Tonic/ Tonic-Clonic

  7. Absence Seizure 3 Hz spike and wave

  8. Seizure vs Epilepsy Seizures Nonepileptic Epilepsy (recurrent seizures) Cardiovascular Drug related Syncope Metabolic (glucose, Na, Ca, Mg) Toxic (drugs, poisons) Poison Infectious Febrile convulsions Nonepileptic seizures Alcohol/drug withdrawal Substance abuse Psychiatric disorders Sleep disorders (parasomnias, cataplexy) Idiopathic (primary) Symptomatic (secondary)

  9. Epidemiology of Seizures and Epilepsy Epilepsy: Incidence Rates by Seizure Type Data from Rochester, Minn (1935-1979). Adapted with permission from Annegers JF. In: The Treatment of Epilepsy: Principles and Practice. 2nd ed. Baltimore, Md: Williams & Wilkins; 1997:165-172. Hauser et al, 1992 Ramsay RE, et al. Neurology. 2004;62(5 suppl 2):S24-S29 . * Includes known etiologies such as arteriovenous malformation and venous angioma.

  10. Seizure Precipitants Low (less often high) blood glucose Low sodium Low calcium Low magnesium Stimulant or other proconvulsant toxicity (i.e., cocaine) Sedative (i.e., valium or alcohol) withdrawal Severe sleep deprivation

  11. EEG Abnormalities • Background abnormalities • -Significant asymmetries and/or degree of slowing inappropriate for clinical state • Transient abnormalities associated with seizures • -Spikes (< 70 m sec) • -Sharp waves (~70 – 200 msec) • -Spike-wave complexes • May be focal, lateralized or generalized

  12. EEG Abnormalities

  13. Treatment of New Onset Epilepsy Kwan P, Brodie MJ. N Engl J Med 2000; 342: 314-9.

  14. Kwan and Brodie. NEJM 2000; 342: 314-319. Mohanraj and Brodie. Epil Behav 2005; 6: 382-387

  15. Kwan and Brodie. NEJM 2000; 342: 314-319. Mohanraj and Brodie. Epil Behav 2005; 6: 382-387

  16. Rational Use of AEDs: All PrescriptionsMarket Dynamics for All Indications and Epilepsy AED Prescription Volume (%) 0-17 18-34 35-44 45-54 55-64 >65 PharMetrics. April2002 to June 2003. Source: IMS NPA, Dec. 2003 MAT 03/2004 Age Group (years)

  17. “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy.” Paracelsus (1493-1541)

  18. Summary of Serious and Non-serious Adverse Events of the Newer AEDs

  19. Rational Use of AEDsSo Why Should Prescribing Practices Change? Patients often required long term (or lifetime) treatment due to driving status • State of Florida *15A-5.004 Neurological Guidelines for Applicants with Seizures(*the following changes to the seizure guidelines became effective in August 1992 and have been used as policy since that date) • Applicants and licensed drivers should be seizure free for a period of 2 years before being approved for licensing; but if under regular medical supervision, may apply at the end of 6 months for review by the Medical Advisory Board. “Petit mal” or absence seizures and partial seizures with complex symptomology will also follow these guidelines. The isolated seizure with a normal EEG may be reviewed after 3 months. • Applicants and licensed drivers who have been approved after 6 months seizure free may be required to submit follow-up reports at the end of 1 year from the date of approval. • Applicants and licensed drivers who have a chronic recurring seizure disorder (or who have been treated for such for 1 year) and medications have been discontinued will not be licensed to drive during the period of drug withdrawal and for a period of 3 months following complete cessation of treatment. If the patient has seizures during this period, licensing may be considered after a 3 month seizure free interval upon return to adequate therapy. • If there is a question about the seizure type or the medications the applicant of licensed driver is on, it is the prerogative of the Medical Advisory Board to question the treating physician further in an effort to clarify the nature of the seizures. • Blood levels below therapeutic levels are to be considered on an individual basis. • Applicants and licensed drivers with only chronic nocturnal seizures will be considered on an individual basis. • Applicants and licensed drivers with syncopal episodes who have no clear diagnosis established will be considered on an individual basis

  20. Treatment/Evaluation Sequence for Pharmacoresistent Epilepsy 1st Monotherapy AED Trial 2nd Monotherapy AED Trial 3rd Monotherapy/Polytherapy AED Trial Strongly consider videoEEG Monitoring Kwan P, Brodie MJ. NEJM;342:314-319. Non-epileptic Epilepsy Psychogenic, migraine, syncope, sleep disorders, movement disorder’s, etc. Epilepsy Surgery/VNS Therapy/ Neuropace Evaluation Polytherapy AED Trials Resective Surgery Stimulator Therapy

  21. Other Treatments of Epilepsy • Medical • Experimental AED trials • Ketogenic diet • Surgical • Resective • Multiple Subpial Transection • Vagal Nerve Stimulator • Experimental • Thalamic Stimulators • Stereotactic Radiosurgery • Responsive Neurostimulators

  22. Evaluation for Surgery- Neuroimaging • MRI • -hippocampal volumetrics • greater than ~0.5cc difference increases chances for seizure remission • -1.5 mm coronal cuts with sequences sensitive to gray-white differentiation and to gliosis • -inversion recovery/high resonance for cortical dysplasia • PET • Ictal/interictal SPECT • MR Spectroscopy • Decreased NAA (due to neuronal loss) • Normal to high Cho and Creatine (represents astrocytosis)

  23. Epilepsy Surgery- Neuroimaging Hippocampal atrophy in temporal lobe epilepsy Ganglioglioma Dysembryoplastic Neuroepithelial Tumor Cortical Dysplasia AVM Cavernous Angioma

  24. Evaluation for Surgery- Subdural Grid Electrodes

  25. Left Anterior Temporal Loectomy

  26. Factors Affecting Adaptation in Epilepsy Seizure-RelatedVariables Treatment-Related Variables Non–Seizure-RelatedVariables

  27. Factors Affecting Cognitive Function in Epilepsy Seizure-RelatedVariables Treatment-Related Variables Non–Seizure-RelatedVariables

  28. What Seizure Related Factors May Affect Cognition in Epilepsy? SeizureSyndrome Onset Age Etiology SeizureBurden(Duration,Frequency,Status) EpileptiformActivity

  29. Seizure-Related Variables That May Affect Cognition and Behavior Ageat Onset SeizureSyndrome Etiology SeizureBurden(Duration,Frequency,Status) EpileptiformActivity

  30. Epileptic Syndrome • Some epilepsy syndromes are known to be associated with more adverse cognitive consequences than others. • Idiopathic Benign syndromes—e.g., BECTS (Rolandic), absence • Adverse syndromes—e.g., Lennox-Gastaut • Variable syndromes—Localization related epilepsies

  31. Idiopathic Syndromes Elger et al. (2004)

  32. Adverse Syndromes Elger et al. (2004)

  33. Localization Related Syndromes Elger et al. (2004)

  34. Seizure-Related Variables That May Affect Cognition and Behavior Ageat Onset EpilepticSyndrome Etiology SeizureBurden(Duration,Frequency,Localization) InterictalEpileptiformActivity

  35. Less Education Decreased rates of employment Lower rates of marriage Poorer physical health Increased incidence of psychiatric disorders Adults with Childhood Seizure Onset Jalava et al., 1997a,b,c, Sillanpää (1998)

  36. Total and Segmented Volumes(7.8 years vs. 23.3 years) Hermann et al, Epilepsia 2002;43:1062-71

  37. Total Lobar White Matter Hermann et al, Epilepsia 2002;43:1062-71

  38. Cause or Effect? • Does white matter volume abnormality reflect neurodevelopmental abnormality associated with early insult to developing brain? • Does early lesion affect subsequent normal development of white matter connectivity?

  39. Age of Onset and Neuropsychological Outcome Early Late Healthy (7.8 yr) (23.3 yr) Controls N 37 16 62 FSIQ 90* 100 107 Naming 47 52 55 Verbal Mem 44 51 52 NV Mem 46 55 62 WCST PE 13 8 8 Hermann et al, Epilepsia 2002;43:1062-71

  40. Childhood TLE Onset • Generalized cognitive compromise • Reduction in cerebral volume, particularly white matter (~6-12%) • Cerebral volume reduction not limited to temporal lobe • Less focal impairment (e.g., memory) • Less surgical risk • Greater likelihood of functional reorganization (e.g., bilateral language, pathologic left handedness)

  41. Seizure-Related Variables That May Affect Cognition and Behavior Ageat Onset SeizureSyndrome Etiology SeizureBurden(Duration,Frequency,Localization) EpileptiformActivity

  42. Etiology • Individuals with known causes for their epilepsy (e.g., head injuries, brain infections) typically have more detectable cognitive difficulties than those with no known etiology

  43. Seizure-Related Variables That May Affect Cognition and Behavior Ageat Onset SeizureSyndrome Etiology SeizureBurden(Duration,Frequency,Localization) EpileptiformActivity

  44. Seizure Burden • Individuals with poorly controlled and severe seizures often have more detectable cognitive consequences than individuals with well-controlled and/or minor seizures

  45. Cumulative Seizure Effects?(is epilepsy progressive?) • Structural Imaging vs Behavior • Cognitive and behavioral impairments present prior to treatment • Newly diagnosed L TLE patients have verbal memory impairment Äikiä, Epilepsy & Behavior (2001) Äikiä , Epilepsy Research 1995;22:157-164

  46. Progressive Hippocampal Sclerosis • Progressive hippocampal atrophy occurred only in patients with TLE and continuing seizures • n=12 unilateral TLE • Repeat MRI=2.5-5.2 yr • Fuerst et al, Ann Neurol 2003;53:413-6

  47. Neuropsychological Effects of Poorly Controlled Seizures • 20 longitudinal studies in children-adults • 12/20 reported relationship/decline • 5/20 mixed results • 3/20 no relationship Dodrill, Epilepsy & Behavior (2004)

  48. Neuropsychological Effects of Seizures • Decreased scores with higher number of seizures • IQ lower with increased seizure frequency • Greater performance “improvement” in controls than patients • Losses seen beyond “memory” Dodrill, Epilepsy & Behavior (2004)

  49. Cross-sectional TLE Neuropsychological Outcome Jokeit et al, JNNP 1999;67:44-50

  50. Educational Attainment and Seizure Duration Jokeit et al, JNNP 1999;67:44-50

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