Lesional Epileptic Negative Myoclonus (ENM) - Anatomo-Electro-Clinical Correlations.
Abstract number :
1.150
Submission category :
Year :
2001
Submission ID :
1179
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
H. Holthausen, MD, Neuropediatric Clinic, BHZ Vogtareuth, Vogtareuth, Bavaria, Germany; T. Pieper, MD, Neuropediatric Clinic, BHZ Vogtareuth, Vogtareuth, Bavaria, Germany; S. Noachtar, MD, Neurology, Ludwig-Maximilians-University, Munich, Bavaria, Germany
RATIONALE: a) To investigate whether there is a correlation between the localization and the size of the lesion and the clinical expression of the ENM (epileptic negative myoclonus).
b) To investigate whether ENM are spontaneous events or caused by stimuli or triggering mechanisms.
METHODS: Methods and Patients:
ENM was diagnosed in 11 patients (3 female, 8 male; 10 were children, age range 2-12 years; in 9/11 ENM was documented by polygraphic recording during 3 pre-surgical evaluation because of severe drug resistent seizures; in 2 out-patients the diagnosis was made on the basis of the observation of ENM during the neurological examination.
10/11 patients had lesions on MRI (dysplastic N=8; posttraumatic N=1; perinatal watershed lesion N=1); FCD was found on pathology post epilepsy surgery in 1 patient.
Localization of the lesion: well-circumscribed /restricted to one lobe N=6;
Hemispheric damage or dysplasia of one hemisphere N=5.
RESULTS: ENM was [dsquote]generalized[dsquote] in 7 patients = sudden loss of muscle tone in trunk and all 4 extremities causing sudden falls (with preservation of consciousness), and focal = involvement of one upper extremity only in 4 patients.
No correlation was found between the localization and the size of the lesion and the type of ENM: 4/6 patients with well-circumscribed lesions had [dsquote]generalized[dsquote] ENM; 2/5 patients with hemispheric lesions had [dsquote]focal[dsquote] ENM.
ENM was triggered by somato-sensory input (e.g. activation of trunk / neck / arm / finger)in 10/11 patients, causing status-like periods lasting days and weeks in 4 patients during which they were unable to walk or sit independently.
CONCLUSIONS: Like with other focal seizures, the clinical expression of the ENM depends more often on activation of a symptomatogenic zone by means of seizure-spread than on the localization and the size of the lesion.
This study confirms the concept that ENM is a cortical reflex negative myoclonus.
Moreover, very small lesions, not visible on MRI can cause [dsquote]generalized[dsquote] drop attacks, which might errorneously lead to diagnoses like [dsquote]myoclonic-astatic epilepsy[dsquote] or other types of generalized epilepsies.