A motor feature involves motor activity and may consist of an increase (positive) or decrease (negative) in muscle contraction. Motor features may be elementary or complex.

Elementary motor

An elementary motor feature involves a stereotyped contraction of a muscle or group of muscles. Such motor features may be predominantly convulsive Convulsive: rhythmic jerking (clonic activity), may occur alone or in combination with tonic activity. (e.g. hemiclonic Hemiclonic: rhythmic jerking (clonic activity) involving only one side of the body), myoclonicMyoclonic: a single or short cluster of brief muscle contractions (jerks). Each jerk is typically milliseconds in duration., tonicTonic: increased muscle tone, usually lasting for seconds to minutes., epileptic spasmEpileptic spasm: sudden flexion, extension or mixed flexion-extension of proximal and truncal muscles, lasting 1-2 seconds, typically occurs in a series, versiveVersive: sustained, forced conjugate ocular, cephalic, and/or truncal rotation or lateral deviation from the midline. or dystonicDystonic: sustained contractions of both agonist and antagonist muscles producing athetoid or twisting movements, may produce abnormal postures..

Complex motor

A complex motor feature involves complex movement patterns. Three types are recognized:

  • A hypermotor feature involves proximal limb or axial muscles, producing irregular large amplitude ballistic movements, such as pedaling, pelvic thrusting, jumping, thrashing and/or rocking movements.
  • A negative motor feature is characterized by reduced motor activity.
  • An automatism is a coordinated, repetitive motor activity usually occurring when cognition is impaired and for which the subject is usually amnesic afterward. This often resembles a voluntary movement and may consist of an inappropriate continuation of pre-ictal motor activity. Automatisms include:
    • Oroalimentary: lip smacking, lip pursing, chewing, swallowing, clicking.
    • Manual or pedal: bilateral or unilateral distal or proximal movements, including fumbling, tapping, manipulating movements of hands or feet.
    • Gestural: often unilateral, fumbling or exploratory movements with the hand intended to lend emotional tone to communication.
    • Gelastic: bursts of laughter or giggling, usually without appropriate affective tone and described as 'mirthless'. This is characteristic of seizures arising in the hypothalamus, but can occur in seizures arising in the frontal or temporal lobes.
    • Vocal: single or repetitive sounds such as shrieks or grunts
    • Verbal: single or repetitive words, phrases or brief sentences.
    • Dacrystic: outbursts of crying.

Focal seizure evolving to a bilateral convulsion

A focal seizure may spread to involve both hemispheres, resulting in bilateral convulsive features. This was previously known as a 'secondary generalized seizure'. Motor components in such a situation may include tonic or clonic features.

Epilepsia partialis continua

Epilepsia partialis continua refers to recurrent focal motor seizures (typically affecting hand and face, although other body parts may be affected), that occur every few seconds or minutes for extended periods (days or years). The focal motor features may exhibit a Jacksonian march. A Todd's paresis may be seen in the affected body part.

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