PSYC4080 Seizure Disorders 1. PSYC4080 Seizure Disorders 2 Abnormal electrical discharge in the brain. Neurons firing together in synchrony: paroxysmal

PSYC4080PSYC4080 Seizure DisordersSeizure Disorders 11

Seizure DisordersSeizure Disorders


Seizure DisordersSeizure Disorders Abnormal electrical discharge in the brain.Abnormal electrical discharge in the brain. Neurons firing together in Neurons firing together in synchrony: synchrony: paroxysmal depolarization shifts (PDS)paroxysmal depolarization shifts (PDS)

Hyperexcitation of glutamate neurons.Hyperexcitation of glutamate neurons. Many causes: Seizures are symptoms, not a Many causes: Seizures are symptoms, not a disease.disease.

Presence of sensory or cognitive Presence of sensory or cognitive dysfunction is dependent on affected dysfunction is dependent on affected area(s)area(s)

Prevalence: 0.6% of the populationPrevalence: 0.6% of the population Incidence: 15,500 new cases per year Incidence: 15,500 new cases per year (Epilepsy Canada)(Epilepsy Canada)


NeuropathologyNeuropathology

1.1. Generalized seizures – involve the entire Generalized seizures – involve the entire cerebral cortexcerebral cortex

2.2. Focal (partial) seizures – limited to parts of Focal (partial) seizures – limited to parts of the brain the brain

PDS associated with a spike in the EEGPDS associated with a spike in the EEG


NeuropathologyNeuropathologyTypical Muscle Movements:Typical Muscle Movements:

1.1. Tonic: stage of extreme muscle tension related to Tonic: stage of extreme muscle tension related to PDS activityPDS activity

2.2. Clonic: contractions and relaxations of muscle, Clonic: contractions and relaxations of muscle, occurring in rapid successionoccurring in rapid succession• Rapid onset and offset of PDS activityRapid onset and offset of PDS activity• EEG changes during and between seizures (ictal and EEG changes during and between seizures (ictal and

interictal periods).interictal periods).

3.3. Atonic: no muscle tensionAtonic: no muscle tension

Level of ConsciousnessLevel of Consciousness1.1. Simple: No lossSimple: No loss2.2. Complex: Loss of consciousnessComplex: Loss of consciousness


NeuropathologyNeuropathology Hyper-excitability in neurons can Hyper-excitability in neurons can accelerative cell deathaccelerative cell death

High concentration of CaHigh concentration of Ca++++ leads to long- leads to long-term potentiation of synaptic responsesterm potentiation of synaptic responses• Activation of genes that cause synaptic Activation of genes that cause synaptic reorganizationreorganization

• Axonal growth and neo-synaptogenesis Axonal growth and neo-synaptogenesis • Lowering of seizure thresholdLowering of seizure threshold

Children’s brains are more resistant to Children’s brains are more resistant to these long term effectsthese long term effects• Relative immaturity of biochemical cascadesRelative immaturity of biochemical cascades


Childhood Seizure Childhood Seizure DisordersDisorders

1.1. Neonatal seizuresNeonatal seizures Occurring up to 2 months of ageOccurring up to 2 months of age

Symptoms are acute not chronicSymptoms are acute not chronic

Full body tonic and clonic movementsFull body tonic and clonic movements Loss of consciousnessLoss of consciousness More common in premature infants More common in premature infants 90% of patients die from these seizures.90% of patients die from these seizures.



Many different diseases cause infantile Many different diseases cause infantile seizures: seizures:

Birth trauma or head injuryBirth trauma or head injury Disorders of metabolismDisorders of metabolism Infections (I.e. herpes encephalitis)Infections (I.e. herpes encephalitis) Anoxic episodes (loss of oxygen)Anoxic episodes (loss of oxygen) Genetic factors (I.e. family histories)Genetic factors (I.e. family histories)

40% have no known cause (idiopathic 40% have no known cause (idiopathic epilepsy)epilepsy)

90% have first onset before age 20.90% have first onset before age 20.



2. Infantile spasms (West Syndrome)2. Infantile spasms (West Syndrome) Later onset (3-6 months)Later onset (3-6 months) Full body (tonic) contraction, bending Full body (tonic) contraction, bending over, stiff musclesover, stiff muscles May have up to 100 spasms per dayMay have up to 100 spasms per day

Abnormal EEG, MR are associated with this Abnormal EEG, MR are associated with this syndrome.syndrome.

More common in males.More common in males.Poor prognosis for mental development.Poor prognosis for mental development.Developmental disabilities are common: Developmental disabilities are common: Only 16% can be educated in a normal Only 16% can be educated in a normal classroom settingclassroom setting



3. Febrile seizures3. Febrile seizures Common response to elevated body temperature.Common response to elevated body temperature. 2-5% of all children between 6 months and 5 2-5% of all children between 6 months and 5 years.years.

Full body seizure, tonic and clonic movementsFull body seizure, tonic and clonic movements

More common in males.More common in males. Good prognosis: Good prognosis: Usually no problems later in Usually no problems later in life.life. Exception to this is if the fever was due to a Exception to this is if the fever was due to a brain infection, or if there is a recurrence of brain infection, or if there is a recurrence of seizures after a feverseizures after a fever



1.9% of all children have at least one 1.9% of all children have at least one epileptic episode.epileptic episode.

Most frequent onset between 6 months and 6 Most frequent onset between 6 months and 6 years of age.years of age.


Adult DisordersAdult Disorders

Most common types of seizures:Most common types of seizures:

1.1. Grand malGrand mal: loss of consciousness, falling : loss of consciousness, falling on the ground, and tonic-clonic movementson the ground, and tonic-clonic movements

2.2. Myoclonic seizuresMyoclonic seizures: clonic movements in : clonic movements in parts of the body, usually no loss of parts of the body, usually no loss of consciousnessconsciousness

3.3. Absence seizureAbsence seizure: loss of consciousness : loss of consciousness with no muscle movementswith no muscle movements

4.4. Complex partial seizuresComplex partial seizures: loss of : loss of consciousness, oral automatisms, preceded consciousness, oral automatisms, preceded by auras (sensory warning of seizure by auras (sensory warning of seizure onset).onset).


NeuropathologyNeuropathologySeizures may be Seizures may be intractableintractable and require and require

regular follow-upsregular follow-ups

Those at increased risk:Those at increased risk:1.1. Very young age of onset (< 2 years) Very young age of onset (< 2 years) 2.2. Frequent generalized seizuresFrequent generalized seizures3.3. Failure to achieve control readilyFailure to achieve control readily4.4. Evidence of brain damageEvidence of brain damage5.5. A specific causeA specific cause6.6. Severe EEG abnormalitySevere EEG abnormality7.7. Low IQLow IQ8.8. Atonic, atypical absence seizuresAtonic, atypical absence seizures



Why are children so vulnerable?Why are children so vulnerable? GABAergic synapses develop before main GABAergic synapses develop before main glutamate receptors (NMDA, AMPA)glutamate receptors (NMDA, AMPA)

In early development, GABA is In early development, GABA is excitatoryexcitatory----binding to GABAbinding to GABAAA receptors causes receptors causes depolarization.depolarization.• Shift to inhibitory effects occurs once Shift to inhibitory effects occurs once glutamate receptors have maturedglutamate receptors have matured

Thus, the neonatal brain operates with Thus, the neonatal brain operates with very little inhibition.very little inhibition.



Overt psychosocial and cognitive Overt psychosocial and cognitive consequencesconsequences Including a profound fear of having a seizure Including a profound fear of having a seizure in publicin public

Higher incidence of adjustment, academic, Higher incidence of adjustment, academic, psychiatric disorders in persons with psychiatric disorders in persons with epilepsy (Bennett, 1992). epilepsy (Bennett, 1992).

Lower IQ is associated with seizures, Lower IQ is associated with seizures, especially if the onset is early.especially if the onset is early.

Affected by underlying causes and Affected by underlying causes and medications used to treat as well. medications used to treat as well.



Temporal lobe, and the hippocampus in Temporal lobe, and the hippocampus in particular, may be particularly vulnerableparticular, may be particularly vulnerable Most sensitive to effects of long term Most sensitive to effects of long term potentiation related to memorypotentiation related to memory

Memory and learning deficits may be associated Memory and learning deficits may be associated with any type of seizure.with any type of seizure.

Worst in complex partial seizures which Worst in complex partial seizures which are caused by temporal lobe lesions.are caused by temporal lobe lesions.

Overall attention levels can be affected Overall attention levels can be affected by most types of seizures.by most types of seizures.



High “comorbidity”High “comorbidity”

1.1. DepressionDepression• Major depressive episodes are commonMajor depressive episodes are common• May be related to anticonvulsant May be related to anticonvulsant

medicationsmedications

2. Anxiety Disorders2. Anxiety Disorders• Almost exclusively based on realistic fear Almost exclusively based on realistic fear

of having a seizure in publicof having a seizure in public

3. Personality and Psychotic Disorders3. Personality and Psychotic Disorders Obsessive compulsiveObsessive compulsive Personality changesPersonality changes


Other InformationOther Information

Treatment Options Treatment Options MedicationsMedications Surgery Surgery

• Lesioning tissue if seizures are localLesioning tissue if seizures are local• Electrode stimulationElectrode stimulation

Ketogenic diet (high fat, low carb) - for Ketogenic diet (high fat, low carb) - for generalized seizuresgeneralized seizures

By and large, treatment does not address By and large, treatment does not address psychosocial issues directly. psychosocial issues directly.

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PSYC4080 Seizure Disorders 1. PSYC4080 Seizure Disorders 2 Abnormal electrical discharge in the brain. Neurons firing together in synchrony: paroxysmal