Seizure Semiology & Localization Flashcards

Flashcards covering seizure semiology, lateralizing/localizing signs, pediatric and adult epilepsy syndromes, EEG patterns, surgical candidates, and neurocritical care.

Epigastric aura

Suggests seizure onset in the mesial temporal lobe, commonly seen in temporal lobe epilepsy (TLE).

Excessive salivation during a seizure

Often indicates seizure spread to the temporal lobe, insula, or frontal operculum, and involves autonomic symptoms.

Déjà vu or jamais vu

Experiential auras, often associated with the temporal lobe, especially the mesial temporal structures.

Ictal speech arrest

The dominant hemisphere (usually left), especially in frontal or temporal lobe seizures.

Automatisms such as lip-smacking or hand fumbling

Focal impaired awareness seizures (complex partial), commonly from the temporal lobe.

Fencing posture

Supplementary motor area (SMA), usually on the contralateral side of the extended arm.

Fear or a sudden feeling of doom as an aura

A temporal lobe seizure, especially involving the amygdala.

Hypermotor behavior during a seizure

Likely frontal lobe seizures, often during sleep, with rapid onset and short duration.

Ictal speech preservation in a right-handed individual

Likely non-dominant hemisphere, especially in right temporal lobe seizures.

Ictal head version to one side

The head turns away from the seizure focus (i.e., version is contralateral to the onset zone).

Ictal speech during a seizure

Suggests seizure onset in the non-dominant hemisphere (typically right hemisphere in right-handed individuals).

Gelastic seizures

Hypothalamus, often due to a hypothalamic hamartoma.

Postictal nose-wiping with one hand

The ipsilateral hemisphere to the hand used for wiping is often the seizure focus.

Dystonic posturing of one limb during a seizure

Dystonia is usually contralateral to the seizure focus.

Ictal eye deviation

Away from the seizure focus (i.e., contralateral eye deviation).

Repetitive blinking or chewing movements

Automatisms, commonly seen in temporal lobe seizures.

Sudden behavioral arrest

Often a focal impaired awareness seizure, typically from the temporal or frontal lobes.

Vertigo or spinning in seizure semiology

May suggest involvement of the parietal lobe or vestibular cortex (e.g., temporoparietal junction).

Visual hallucinations at seizure onset

Occipital lobe, especially if simple visual phenomena (flashes, shapes, colors).

Typical duration and pattern of frontal lobe seizures

They are usually brief, occur during sleep, and may involve hypermotor activity, bizarre behavior, and rapid recovery.

Infantile spasms (West Syndrome)

Clusters of sudden flexor/extensor spasms, often on awakening; EEG shows hypsarrhythmia.

Sudden loss of tone in toddlers

Atonic seizures, commonly seen in Lennox-Gastaut syndrome.

Benign epilepsy with centrotemporal spikes (BECTS)

Facial twitching, drooling, often during sleep, with preservation of awareness.

Eye fluttering, brief arrest, and automatisms in school-aged children

Absence seizures (generalized); EEG shows 3 Hz spike-and-wave discharges.

Gelastic seizures in children

Involuntary laughter without emotional cause, often from hypothalamic hamartoma.

Dystonic posturing during a seizure

Contralateral to the seizure onset zone.

Unilateral clonic activity in one limb

Contralateral hemisphere.

Postictal paresis (Todd’s paralysis)

Contralateral to the side of motor weakness—helps lateralize seizure onset.

Ictal head/eye deviation

The head/eyes turn away from the seizure focus (contralateral version).

Unilateral automatisms with contralateral tonic posturing

Seizure likely starts in the hemisphere opposite the tonic posture and same side as the automatism.

Typical behavior after a generalized tonic-clonic seizure

Postictal confusion, sleepiness, muscle soreness, and sometimes transient weakness (Todd’s paralysis).

Postictal nose-wiping with one hand

An ipsilateral sign—nose-wiping occurs on the same side as the seizure onset.

Postictal aphasia in a right-handed person

Seizure involved the dominant hemisphere (usually left).

Postictal urinary incontinence

Generalized tonic-clonic seizures—a nonspecific postictal feature.

Postictal state duration

Longer with generalized seizures; brief or absent in focal aware seizures.

Ictal crying (dacrystic seizure)

Can be seen in hypothalamic hamartomas or temporal/limbic seizures.

Seizure type often presents with sudden head drops in children with developmental delays

Atonic seizures.

Pediatric epilepsy syndrome includes cognitive regression and continuous spike-wave discharges during sleep

Electrical Status Epilepticus in Sleep (ESES), often seen in Landau-Kleffner syndrome.

Asymmetric tonic limb posturing in an infant

Focal seizure; may indicate early-onset epileptic encephalopathy.

Kind of seizure that has a tonic phase followed by clonic jerking and postictal sleepiness

Generalized tonic-clonic seizure.

Early-onset epilepsy with developmental delay and multiple seizure types

Lennox-Gastaut Syndrome.

Expected EEG finding in benign occipital epilepsy of childhood

Occipital spikes, often with visual symptoms like hallucinations or blindness.

Unilateral eye blinking during seizures

Ipsilateral to the seizure onset zone.

Age group that febrile seizures are most common

6 months to 5 years; usually generalized tonic-clonic.

Seizure sign involves a stiff, upright posture with arms flexed and extended at the elbows

Tonic seizure, common in Lennox-Gastaut syndrome.

Behavior after a seizure might suggest non-convulsive status epilepticus

Prolonged confusion, altered awareness, minimal motor activity, and ongoing EEG seizure patterns.

Ictal symptom often accompanies temporal lobe seizures involving the insula

Throat constriction, choking sensation, or chewing automatisms.

Lobe is likely involved in seizures that start with vertigo or spatial disorientation

Parietal lobe.

Typical EEG finding during absence seizures

3 Hz generalized spike-and-wave discharges.

Ictal vomiting

May localize to the insula or temporal lobe.

Hallmark EEG pattern in infantile spasms

Hypsarrhythmia – chaotic, high-amplitude slow waves with multifocal spikes.

EEG pattern associated with Lennox-Gastaut Syndrome

Slow spike-and-wave discharges (1.5–2.5 Hz) during wakefulness; paroxysmal fast activity during sleep.

Interictal EEG pattern seen in Benign Rolandic Epilepsy (BECTS)

Centrotemporal spikes, especially during sleep.

EEG finding typical of absence seizures during hyperventilation

Generalized 3 Hz spike-and-wave discharges, usually lasting <15 seconds.

EEG correlate of focal aware seizures with epigastric aura

Rhythmic theta or sharp waves over the anterior temporal electrodes (e.g., T3/T4, F7/F8).

Periodic lateralized epileptiform discharges (PLEDs)

Acute focal cerebral dysfunction, often seen in stroke, tumor, or herpes encephalitis.

Electroclinical features of a temporal lobe seizure on EEG

Rhythmic theta or delta activity, often starting in T3/T4 or F7/F8, possibly with spreading.

EEG feature is common in frontal lobe seizures

Brief bursts of low-voltage fast activity, or often electrodecremental onset.

EEG pattern associated with generalized tonic-clonic seizures

Bilateral onset with generalized polyspike-and-wave, followed by diffuse suppression postictally.

Generalized periodic discharges (GPDs) suggest in critically ill patients

Encephalopathy, metabolic or hypoxic injury; may indicate NCSE (nonconvulsive status epilepticus).

Epilepsy syndrome is most often associated with surgical treatment

Mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis.

Imaging finding supports temporal lobectomy in MTLE

Hippocampal atrophy and signal changes on MRI (T2/FLAIR hyperintensity).

Goal of invasive EEG monitoring (e.g., SEEG or grids/strips)

To localize the seizure onset zone when scalp EEG is inconclusive.

Seizure semiology best predicts surgical success in TLE

Focal impaired awareness seizures with epigastric aura and automatisms, concordant with MRI and EEG.

Non-invasive studies are typically done for surgical epilepsy evaluation

MRI, PET, SPECT, neuropsychological testing, video-EEG, and functional mapping.

The most common epilepsy syndrome treated with surgery in children

Hemimegalencephaly or focal cortical dysplasia, often requiring hemispherotomy or lobectomy.

Epilepsy syndrome may lead to corpus callosotomy in children

Lennox-Gastaut Syndrome, particularly for drop attacks (atonic seizures).

Main surgical option for hypothalamic hamartomas causing gelastic seizures

Stereotactic laser ablation or open surgical resection, depending on lesion accessibility.

Key signs that a child might benefit from epilepsy surgery

Intractable seizures, focal findings on EEG/MRI, and developmental regression or plateauing.

Risk of delaying epilepsy surgery in pediatric candidates

Risk of cognitive decline, behavioral issues, and permanent neurodevelopmental deficits.

Why is early surgical referral important in children with intractable epilepsy

To prevent epileptic encephalopathy and maximize neuroplasticity for recovery.

Typical approach if MRI is negative but EEG suggests focal onset in a child

Consider MEG, PET, and possibly SEEG to localize the focus more precisely.

Surgical treatment is used for Rasmussen encephalitis in children

Functional hemispherotomy.

Imaging sign suggests focal cortical dysplasia in children

Blurred gray-white junction, cortical thickening, or transmantle sign on MRI.

Most common pathology found after temporal lobectomy in children

Focal cortical dysplasia, rather than hippocampal sclerosis.

What does PET scan show in interictal epilepsy evaluation

Hypometabolism in the epileptogenic zone.

Ictal SPECT

To identify increased blood flow at the seizure onset zone (hyperperfusion).

Functional MRI (fMRI)

To map language, motor, and sensory areas, minimizing deficits after surgery.

MEG (magnetoencephalography)

Interictal magnetic fields from spikes; helps localize irritative zone, especially when MRI is normal.

Wada test

To determine language and memory lateralization by injecting amobarbital into each carotid artery.

EEG pattern is characteristic of nonconvulsive status epilepticus (NCSE)

Continuous or near-continuous ictal discharges (spike, spike-and-wave, or rhythmic delta/theta) lasting >10 minutes.

EEG finding is associated with herpes encephalitis

PLEDs (Periodic Lateralized Epileptiform Discharges), especially in the temporal lobe.

Generalized periodic discharges (GPDs) on EEG

Diffuse cerebral dysfunction; may be seen in hypoxic injury, metabolic encephalopathy, or NCSE.

EEG pattern is seen after cardiac arrest and may suggest poor prognosis

Burst-suppression, isoelectric EEG, or nonreactive EEG.

EEG with continuous, rhythmic delta activity in a comatose patient

Possible NCSE or severe encephalopathy—requires clinical correlation.

Triphasic waves pattern

Metabolic encephalopathy, especially hepatic or renal failure.

Significance of EEG reactivity in comatose patients

Positive prognostic marker—reactivity to stimuli (pain, sound) suggests better recovery potential.

Burst suppression pattern on EEG

Alternating bursts of activity with flat (suppressed) periods; may be due to anesthesia, deep coma, or severe brain injury.

SIRPIDs (Stimulus-Induced Rhythmic, Periodic, or Ictal Discharges)

EEG discharges provoked by stimulation in ICU patients; may indicate hyperexcitable brain and risk of seizures.

Continuous EEG (cEEG) benefit ICU patients

Detects subclinical seizures, NCSE, and prognostic patterns in real time.

High-risk groups for NCSE in ICU patients

Patients with altered mental status, recent seizures, brain injury, or post-cardiac arrest.

Medication class is first-line for NCSE

Benzodiazepines (e.g., lorazepam), followed by IV antiseizure meds like fosphenytoin or levetiracetam.

Role of EEG in therapeutic hypothermia patients

Assess seizures, prognosis, and monitor for malignant EEG patterns.

Significance of evolving rhythmic EEG patterns in comatose patients

Suggests ictal activity; consider NCSE and initiate treatment.

Tool is used to classify EEG patterns in critical care

American Clinical Neurophysiology Society (ACNS) critical care EEG terminology.

Normal range of intracranial pressure (ICP) in adults

5–15 mmHg. Pressures >20 mmHg are considered elevated and may require treatment.

Common causes of elevated ICP

Traumatic brain injury, hydrocephalus, intracranial hemorrhage, tumors, cerebral edema, and venous sinus thrombosis.

Elevated ICP on EEG

Diffuse slowing, loss of reactivity, burst-suppression, and eventually electrocerebral silence in severe cases.

Two most common methods of ICP monitoring

Intraventricular catheter (EVD) and Intraparenchymal fiberoptic monitor.

EEG-ICP correlation might suggest impending herniation

Progressive EEG suppression, loss of background reactivity, and pupillary changes—often paralleled by sharp ICP rise.