Subcortical band heterotopia: analysis of 5 cases

Subcortical band heterotopia (SBH) is a diffuse deterioration of cortical development, which is characterized by the location of heterotopic neurons in deep and subcortical regions of the brain parallel to the cortex, which creates the illusion of duplication of the cortex, from what this variant was named the «double cortex» syndrome. 

Data of five patients including three girls and 2 boys  were analyzed. The average age was 12.6 years (from 5 to 15). In all cases, heterotopia was bilaterally symmetrical: in 2 cases — diffuse, in 1 it was fronto-parietal, in 1 — temporal-occipital, and in 1 it was fronto-parietal-occipital. Concomitant cerebral malformations were presented in all patients: ventriculomegaly in 5 cases (100%), frontal pachygyria in 1 case (20.0%), diffuse pachygyria in 1 case (20.0%), and dysgyria in 1 case (20.0%). All 5 (100%) patients had epilepsy. The age of onset of epileptic seizures was 6.1 [5.6; 7.5] years. In 3 (60.0%) people epilepsy was focal, in 2 (40.0%) — generalized. There were the following types of epileptic seizures: infantile spasms — 1 (20.0%), focal — 3 (60.0%), tonic-clonic — 4 (80.0%), myoclonic — 2 (40.0%), attacks of cessation of motor activity — 1 (20.0%), atonic — 1 (20.0%). Status epilepticus and febrile-provoked seizures were no observed in any case. Interictal epileptiform activity was presented in all cases: regional in 3 (60.0%), diffuse in 1 (20.0%), and multiregional + diffuse in 1 (20.0%). Drug resistant course was in 3 (60.0%) people. Intellectual impairments were detected in 3 (60.0%) patients: mild — in 1 (20.0%), moderate — in 1 (20.0%), severe — in 1 (20.0%). In 2 (40.0%) observations, intelligence was intact, and in both cases these were patients without drug-resistant epilepsy and without concomitant pachygyria. Speech disorder was detected in 3 (60.0%) people, mild movement disorders — in 1 (20.0%), microcephaly — in 1 (20.0%). 

Thus, the leading clinical manifestation of SBH is epilepsy with a predominantly drug resistant course. More data are needed on the possibility of using alternative drug treatments.

Contribution:
Kulikova S.L. — concept, study design, patient data collection and analysis, literature review;
Likhachev S.A. — concept, study design;
Zmachynskaya O.L. — article correction, literature review;
Siz M.A. — EEG monitoring analysis of patients, included in the study.
All co-authors — approval of the final version of the manuscript, responsibility for the integrity of all parts of the manuscript.

Acknowledgments. The study had no sponsorship.

Conflict of interest. The authors declare no conflict of interest.

Received: July 20, 2022
Accepted: August 25, 2022
Published: September 30, 2022

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