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Supplementary sensorimotor area seizures in children and adolescents
1Department of Neurology, Cleveland Clinic Foundation, Ohio 44195-5221, USA.
Insights
Diagnosing supplementary sensorimotor area (SSMA) seizures in children is challenging due to subtle symptoms and normal routine EEGs. Prolonged video EEG and MRI are crucial for identifying these pediatric seizures and enabling timely treatment.
Area of Science:
- Pediatric Neurology
- Epileptology
- Neurophysiology
Background:
- Seizures originating from the supplementary sensorimotor area (SSMA) are challenging to diagnose in children.
- While well-documented in adults, pediatric SSMA seizures are underreported despite childhood onset.
Purpose of the Study:
- To describe the clinical characteristics and diagnostic findings of SSMA seizures in pediatric patients.
- To highlight the utility of prolonged video electroencephalography (EEG) and magnetic resonance imaging (MRI) in diagnosing these challenging seizures.
Main Methods:
- Studied 11 children and adolescents diagnosed with SSMA seizures via prolonged video EEG.
- Utilized MRI for lesion detection and subdural EEG in surgical candidates.
Main Results:
- Mean age at onset was 5.8 years, with diagnosis at 12 years.
- Seizures presented with preserved consciousness, nocturnal predominance, and bilateral tonic posturing.
- Routine EEG was often normal, but prolonged EEG revealed focal epileptiform discharges; MRI identified focal lesions in some cases.
- Epilepsy surgery led to seizure freedom or improvement in 5/6 patients.
Conclusions:
- Pediatric SSMA seizures present atypically, often with normal routine EEG, complicating diagnosis.
- Prolonged video EEG and MRI are essential for accurate diagnosis.
- Earlier recognition and diagnosis are critical for effective medical or surgical management of pediatric SSMA seizures.
Rationale:
Some types of seizures in children may be difficult to recognize; the diagnosis of seizures arising near the mesial posterior frontal supplementary sensorimotor area (SSMA) may be especially challenging. Such seizures have been well described in adults, but few pediatric cases have been reported even though onset is typically in childhood.
Methods:
We studied 11 children and adolescents with SSMA seizures diagnosed by prolonged video electroencephalography (EEG).
Results:
Mean age at onset was 5.8 years, and diagnosis by video EEG was made at a mean age of 12 years. Children had at least borderline intelligence and few abnormal findings on neurologic examination. Seizures were typically brief, frequent, and predominantly nocturnal, with bilateral tonic posturing, gross proximal limb movements, and preserved consciousness. Magnetic resonance imaging showed normal findings or a superior or mesial posterior frontal tumor or cortical dysplasia. Routine EEG findings were usually normal, but prolonged EEG showed epileptiform discharges over the vertex. Seizure onset in the region of the SSMA was confirmed by subdural EEG in six patients who were studied for epilepsy surgery. Five patients had seizure-free outcome or worthwhile improvement after operation. Two nonoperated patients are seizure-free on antiepileptic medication, and three are undergoing surgical evaluation.
Conclusions:
Diagnosis of SSMA seizures in children may be challenging because of unusual symptoms (bilateral tonic limb involvement with preserved consciousness) and frequently normal routine EEG findings. Video EEG may be necessary for diagnosis, and magnetic resonance imaging may reveal a focal lesion. Increased recognition of this seizure type in pediatric patients should lead to earlier diagnosis for optimal medical or surgical treatment.