History
The predominant symptoms occurring during a seizure event determine the seizure type. These can be assessed from direct observation or from video recordings (see the video below), but this is relatively rare because most patients with epilepsy never have video recordings. Thus, in most situations, symptom assessment is based on history alone.
For this reason, a purely semiologic classification has been proposed and is in use at some centers. [24, 25, 26] In this system, seizure types include autonomic, dialeptic, simple motor (clonic, tonic, tonic-clonic, epileptic spasm, myoclonic, versive), complex motor (automotor, hypermotor, gelastic), and negative (aphasic, astatic, atonic, akinetic, hypomotor, negative myoclonic). Focal impaired awareness seizures, as defined by the International League Against Epilepsy (ILAE) classification can be equivalent to various categories of the semiologic classification. [1]
A thorough history should be obtained from the patient, the family members, and any relevant witnesses. It is the most important part of investigating a seizure event.
Question the patient regarding any family history of seizures, febrile seizures as an infant, or previous history of traumatic or other brain insults, which may place the patient at a higher risk for seizures. If the patient has a history of seizures, include his or her responses to previous anticonvulsants or surgery and the results of previous cranial magnetic resonance imaging (MRI), electroencephalography (EEG), and video-EEG recordings.
Focal impaired awareness seizures typically last 30 seconds to 2 minutes. Longer seizures may occur when seizures become generalized with full body convulsions or transform to a state of partial status epilepticus.
In particular, ask detailed questions designed to elicit and assess seizure-type behaviors, such as aura, impairment of consciousness, automatisms, focal symptoms (eg, weakness, sensory changes), and postictal behaviors.
Aura
An aura is a subjective sensation and is a simple partial seizure (ie, the initial part during which the patient is aware). Typically, it is of brief duration, rarely lasting longer than seconds. Determining the type of aura present is critical for identifying the site of cortical onset. Eight different varieties are recognized: somatosensory, visual, auditory, gustatory, olfactory, autonomic, abdominal, and psychic.
Auras precede temporal lobe seizures in approximately 80% of cases. The most common auras in temporal lobe seizures are abdominal (a rising epigastric sensation) and psychic aura (fear, déjà vu, jamais vu).
Parietal lobe seizures may begin with a contralateral sensation, usually of the positive type (electrical sensation, tingling). Occipital lobe seizures may begin with contralateral visual changes, usually of the positive type, such as colored lines, spots, or shapes, or even a loss of vision. Temporal-parietal-occipital seizures may produce more formed auras.
Impaired consciousness
Focal impaired awareness seizures, in the ILAE classification, are defined by impairment of consciousness. [1] This implies decreased responsiveness and awareness of one’s self and surroundings. Usually, during a focal impaired awareness seizure, a patient is unresponsive and does not remember events that occurred.
Consciousness may not be impaired completely, however. Although patients typically do not respond to external stimuli, they may make simple verbal responses, follow simple commands, or continue to perform simple or, less commonly, complex motor behaviors (eg, operating a car). Impairments in consciousness should be contrasted with psychic automatisms, in which the patient experiences intense feelings of strangeness.
Focal impaired awareness seizures are roughly equivalent to what used to be known as psychomotor seizures. In the semiologic classification, they are equivalent to automotor seizures (automatisms), whereas seizures with alteration of consciousness without motor phenomena are known as dialeptic seizures.
Automatisms
Automatisms are nonpurposeful, stereotyped, and repetitive behaviors that commonly accompany focal impaired awareness seizures (in the semiologic classification, they define automotor seizures). The behavior is inappropriate for the situation. Patients are usually amnestic to their automatisms. Verbal automatisms range from simple vocalizations, such as moaning, to more complex, comprehensible, stereotyped speech.
The most common automatisms, at least in temporal lobe epilepsy, are oral (eg, lip smacking, chewing, swallowing) and manual (eg, picking, fumbling, patting [2] ). Unilateral manual automatisms accompanied by contralateral arm dystonia usually indicates seizure onset from the cerebral hemisphere ipsilateral to the manual automatisms.
Automatisms can also be more elaborate, coordinated movements involving bilateral extremities. Examples of complex motor automatisms are cycling movements of the legs and stereotyped swimming movements. Bizarre automatisms, such as alternating limb movements, right-to-left head rolling, or sexual automatisms, may occur with frontal lobe seizures.
Automatisms may also occur during nonepileptic states of confusion (eg, metabolic encephalopathy), after ictus, and during absence seizures, especially when prolonged.
Temporal versus extratemporal seizures
Focal impaired awareness seizures can arise from any location but most commonly arise from the temporal lobe (60%). Temporal lobe seizures have highly specific behaviors as compared with extratemporal seizures.
Focal impaired awareness seizures of temporal lobe origin often begin with a motionless stare followed by oral or manual automatisms. Frontal lobe seizures often begin with vigorous motor automatisms or stereotyped clonic or tonic activity. [3] Extratemporal lobe seizures may spread quickly to the frontal lobe and produce motor behaviors similar to those associated with focal impaired awareness seizures of the frontal lobe.
Temporal lobe type seizures (temporal lobe epilepsy) require a treatment approach emphasizing early surgical referral. Careful notation of seizure aura, seizure semiology, and postictal phenomena can give highly sensitive localizable signs and further provide high preoperative value in these cases.
Lateralizing signs with corresponding sensitivities include the following [4, 5] :
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Contralateral - Unilateral sensory aura (89%), hemifield visual/sensory aura (100%), motor version (100%), clonic activity (83%), tonic activity (100%); figure 4 sign (89%); unilateral dystonic posturing (100%); postictal palsy (93%)
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Ipsilateral - Postictal nose wiping (92%)
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Nondominant lobe - Ictal spitting (75%), ictal vomiting (81%), ictal speech (83%)
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Dominant lobe - Ictal aphasia/dysphasia (100%)
Physical Examination
The physical examination is directed so as to elucidate focal cortical neurologic findings, such as aphasia, unilateral neglect, apraxia, or unilateral signs. In the vast majority of patients with focal epilepsies and focal impaired awareness seizures, the neurologic examination yields normal results.
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Note oral and hand automatisms at initiation of event. Patient is not following commands or answering questions during the event.
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Left temporal sharp wave.
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Left temporal lobe seizure.
