| absence | Paroxysmal attacks of impaired consciousness, occasionally accompanied by spasm or twitching of cephalic muscles, which usually can be brought on by hyperventilation; depending on the type and severity of the absence, the EEG may show an abrupt onset of a 3/sec spike and wave pattern as in simple absence, or in atypical cases, a 4/sec spike and wave or faster spike complexes. The clinical states accompanying these EEG abnormalities may be classified as: 1) absence with no overt manifestations, e.g., simple absence; epileptic absence; subclinical absence; 2) absence with clonic movements, e.g., myoclonic absence; 3) absence with atonic states, e.g., atonic absence; 4) absence with tonic contractions, e.g., hypertonic muscular contraction; 5) absence with automatisms, e.g., various stereotyped movements, usually of the face or hands; 6) absence with atypical features, e.g., bizarre motor activity. Origin: L. Absentia (05 Mar 2000) |
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| absence seizure | <neurology> A type of seizure that in contrast to the grand mal seizure, are noted for their brevity and for the degree of loss of awareness (brief staring spell) accompanied by minimal motor manifestations. A common form of childhood epilepsy. (06 Oct 1997) |
| atypical absence seizure | An absence seizure associated with an EEG pattern of irregular or slow spike and wave at less than 2.5 Hz or paroxysmal fast activity on an abnormally slow background EEG. (05 Mar 2000) |
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| childhood absence epilepsy | A generalised epilepsy syndrome characterised by the onset of absence seizures in childhood, typically at age six or seven years. There is a strong genetic predisposition and girls are affected more often than boys. EEG reveals generalised 3 Hz spike-wave activity on a normal background. Prognosis for remission is good if the patient does not also have generalised tonic-clonic seizures. See: absence. Synonym: petit mal epilepsy, pyknolepsy. (05 Mar 2000) |
| congenital absence of pulmonary valve | <radiology> BIG central pulmonary arteries, big RV (12 Dec 1998) |
| pure absence | A brief clouding of consciousness accompanied by the abrupt onset of 3/sec spikes and waves on EEG. Synonym: pure absence. (05 Mar 2000) |
| simple absence | A brief clouding of consciousness accompanied by the abrupt onset of 3/sec spikes and waves on EEG. Synonym: pure absence. (05 Mar 2000) |
| epilepsy, absence | Epileptic seizures that consist of a sudden cessation of ongoing conscious activity without convulsive muscular activity or loss of postural control. These seizures may be so brief as to be inapparent, lasting seconds and occasionally several minutes. Absence seizures usually begin in otherwise neurologically normal children and rarely appear for the first time in adults. The seizures may occur hundreds of times per day and go on for weeks or months before it is recognised that a child is having seizures. (12 Dec 1998) |
| juvenile absence epilepsy | A generalised epilepsy syndrome with onset around puberty, characterised by absence seizures and generalised tonic-clonic seizures. EEG often shows a greater than 3 Hz generalised spike wave pattern. (05 Mar 2000) |