Clinical Seizure Semiology 2

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Questions and Answers

In which ipsilateral hemisphere do unilateral eye blinking seizures primarily lateralize?

Temporal lobe (correct)

Parietal lobe

Frontal lobe

Occipital lobe

What is the suggested mechanism for ictal nystagmus during seizures?

Exhaustion of vestibular system

Inhibition of motor cortex

Activation of cortical saccade areas (correct)

Activation of occipital lobes

Which area is primarily involved in ictal aphasia during seizures?

Superior temporal gyrus

Inferior frontal gyrus (Broca's area) (correct)

Cingulate gyrus

Supramarginal gyrus

What is the relationship between Todd's paralysis and seizure onset?

Contralateral to seizure onset Signup and view all the answers

Which phenomenon defines postictal aphasia?

Involvement of the dominant hemisphere Signup and view all the answers

Which brain region is primarily involved in auditory auras?

Contralateral temporal lobe Signup and view all the answers

What is the most common aura associated with mesial temporal seizure origin?

Abdominal auras Signup and view all the answers

Which aura involves activation of the insula and typically does not lateralize?

Abdominal auras Signup and view all the answers

Which type of auras is characterized by emotional symptoms like fear and anxiety?

Psychic auras Signup and view all the answers

What type of visual aura suggests activation of the geniculostriate radiation?

Visual distortions like macropsia Signup and view all the answers

Which area is primarily stimulated to produce simple visual auras?

Primary visual cortex (V1) Signup and view all the answers

Which type of hallucination is indicative of temporo-occipital junction activation?

Complex visual hallucinations Signup and view all the answers

Which type of aura is often confused with olfactory auras due to overlapping symptoms?

Gustatory auras Signup and view all the answers

Which region is associated with the lateralization of seizure focus through homonymous hemifield defects?

Contralateral infra-calcarine cortex Signup and view all the answers

Activation of which brain structure is most characteristic of emotional auras like fear?

Amygdala Signup and view all the answers

What is the primary role of ictal semiology in relation to ressective epilepsy surgery?

To identify the symptomatogenic zone Signup and view all the answers

Which area of the brain is primarily involved in eliciting clear somatotopic distribution during somatosensory auras?

Contralateral somatosensory cortex Signup and view all the answers

Painful auras are most commonly associated with which symptomatogenic zone?

Postcentral gyrus Signup and view all the answers

What is a characteristic of auditory auras involving simple sounds?

They indicate involvement of the Heschl gyrus Signup and view all the answers

In patients with temporal lobe epilepsy, what can cause ipsilateral sensations during painful auras?

Activation of secondary somatosensory area Signup and view all the answers

How can poorly defined paresthesias manifest during somatosensory auras?

From the activation of adjacent cortical regions Signup and view all the answers

What is a common misconception regarding somatosensory auras?

They must always lateralize clearly Signup and view all the answers

Which of the following statements about ictal discharges and the epileptogenic zone is true?

Ictal discharges can begin in silent areas and still produce symptoms Signup and view all the answers

What is the likely consequence of late ipsiversion at the end of a generalized tonic-clonic seizure?

Predicts ipsilateral seizure focus. Signup and view all the answers

What is the primary cause of unilateral clonic activity during a seizure?

Activation of the primary motor area. Signup and view all the answers

What does the presence of last clonic activity ipsilateral to seizure onset indicate?

Fatigue-induced cessation of activity. Signup and view all the answers

What is the expected lateralization of unilateral dystonic posturing in temporal lobe epilepsy?

Contralateral to seizure onset. Signup and view all the answers

During a tonic phase of a GTC seizure, what does the 'figure-of-4-sign' suggest?

Contralateral arm rigidity. Signup and view all the answers

What is the most common lateralization observed in ictal spitting?

Non-dominant right temporal lobe. Signup and view all the answers

What describes the expected lateralization of ictal vomiting?

Non-dominant hemisphere involvement. Signup and view all the answers

What mechanism might explain unilateral ictal akinesia?

Activation of negative motor areas. Signup and view all the answers

In the context of unilateral clonic activity, which Broadman area is primarily involved?

Broadman area 4. Signup and view all the answers

What is a significant feature of late ipsiversion observed at the end of the GTC seizure?

Indicates exhaustion and inhibition. Signup and view all the answers

Which brain areas are commonly activated during déjà vu sensations?

Uncus and entorhinal cortex Signup and view all the answers

What is true about the occurrence of true vertigo in mesial temporal epilepsy?

It is NOT a feature at the seizure onset. Signup and view all the answers

What does 'ictal urge to urinate' usually signify?

Non-dominant hemisphere involvement Signup and view all the answers

Which symptomatogenic zone is typically involved in genital sensations and orgasmic auras?

Right mesiotemporal and frontal areas Signup and view all the answers

What is the characteristic of head and eye deviation during a seizure?

It may occur before secondary generalization. Signup and view all the answers

Which of the following auras is specifically linked to cardiorespiratory sensations?

Autonomic auras Signup and view all the answers

What percentage of patients undergoing vEEG monitoring studies experience ictal piloerection?

0.15% Signup and view all the answers

What is the primary area associated with the sensation of rotation or movement in auras?

Temporoparietal junction Signup and view all the answers

What is a common misconception about the activation of the insula in autonomic auras?

It participates in multiple types of autonomic auras. Signup and view all the answers

Which area is largely involved in sustained unnatural positioning during seizures?

Motor areas to precentral gyrus Signup and view all the answers

Study Notes

Introduction

Ictal discharges originate from the epileptogenic zone and activate the symptomatogenic zone, producing clinical semiology.
Resective epilepsy surgery requires complete resection of the epileptogenic zone for success.
Patients with lateralizing auras show better surgical outcomes compared to those without.
Ictal semiology reflects the involvement of the symptomatogenic zone, not necessarily the ictal onset zone.

Auras

Somatosensory Auras (SAs):
- Clear somatotopic distribution indicates activation of the contralateral somatosensory cortex (Brodmann areas 3, 1, 2).
- Poorly defined paresthesias may result from the supplementary sensorimotor area (SMA).
- Activation of the superior bank of the Sylvian fissure typically produces distal and bilateral sensations, usually lateralizing but not localizing.
Painful Auras:
- Generally contralateral to seizure onset, activated in the postcentral gyrus and parietal lobe.
- Temporal lobe epilepsy can show ipsilateral sensations due to secondary somatosensory area activation.
Auditory Auras:
- Simple sounds indicate Heschl gyrus involvement (Brodmann 41 and 42); complex sounds involve auditory association cortex (Brodmann areas 42 and sometimes 22).
- Unilateral ear plugging can lateralize to the contralateral temporal lobe; its auditory nature is unclear.
Olfactory Auras:
- Strongly localized to mesial temporal structures, typically involving the amygdala, with possible involvement of the orbitofrontal cortex.
Gustatory Auras:
- Involve activation of the parietal operculum and mesiobasal temporal lobe; challenging to differentiate from olfactory auras.
Visual Auras:
- Simple visual auras suggest occipital seizures (Brodmann 17, 18, 19); static auras usually come from area 17 (V1).
- Homonymous hemifield defects localize the seizure focus to the contralateral hemisphere.
Abdominal Auras:
- Common in mesial temporal seizures; symptomatogenic zone typically in the insula.
Psychic Auras:
- Include emotional symptoms and familiarity distortions; fear indicates amygdala activation.
- Déjà vu sensations usually involve the uncus or entorhinal cortex, while out-of-body experiences involve the temporo-parietal junction.
Autonomic Auras:
- Include cardiorespiratory, GI, and cutaneous sensations, activated by various cortical areas, especially the insula.
- Ictal urge to urinate indicates non-dominant hemisphere involvement.

Lateralizing Ictal Signs

Head and Eye Deviation:
- Mostly contralateral to seizure onset; caused by activation of frontal eye fields and adjacent motor areas.
Unilateral Clonic Activity:
- Typically contralateral to seizure focus; linked to primary motor area activation.
Last Clonic Activity:
- In temporal lobe epilepsy, clonic jerks occur ipsilateral to seizure onset over 80% of the time, likely due to metabolic exhaustion.
Unilateral Dystonic Posturing:
- Reliable lateralizing sign in temporal lobe epilepsy, with high contralateral correlation.
Asymmetric Tonic Posturing:
- Characterized by one arm extended and the opposite flexed; extended arm is typically contralateral to seizure onset.
Ictal Speech:
- Preservation during seizures often lateralizes to the non-dominant hemisphere.
Ictal Nystagmus:
- Often related to seizures from the posterior regions; EEG changes usually contralateral to the fast phase.

Lateralizing Post-Ictal Signs

Todd’s Paralysis:
- Contralateral to seizure onset, likely due to exhaustion of primary motor areas.
Postictal Aphasia:
- Indicates involvement of language-dominant hemisphere, differentiated from postictal confusion.
Postictal Nosewiping:
- Common in temporal lobe epilepsy, occurring ipsilateral to the seizure onset in 75-90% of cases; exact mechanism remains unclear.

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Description

Explore the critical aspects of clinical seizure semiology, focusing on the lateralization and localization of ictal discharges. This quiz discusses the relationship between the epileptogenic zone and the symptomatogenic zone, which plays a crucial role in understanding seizure presentations and effective surgical interventions.