Multifocal spatiotemporal distribution of interictal spikes in Panayiotopoulos syndrome
Vasileios Kokkinos1, Michalis Koutroumanidis, Katerina Tsatsou
1Department of Clinical Neurophysiology and Epilepsies, Guy's, St. Thomas' and Evelina Hospital for Children, NHS Foundation Trust, London, United Kingdom.
Insights
Panayiotopoulos syndrome (PS) involves interictal spikes originating independently from multiple brain areas, not just the occipital lobe. This finding reclassifies PS as a multifocal epileptic syndrome, expanding diagnostic understanding.
Area of Science:
- Epilepsy research
- Neurophysiology
- Pediatric neurology
Background:
- Panayiotopoulos syndrome (PS) is a common childhood epilepsy syndrome.
- The origin and propagation patterns of interictal spikes in PS are not fully understood.
- Investigating spike origins is crucial for accurate diagnosis and classification.
Purpose of the Study:
- To investigate the spatiotemporal dynamics of interictal spikes in Panayiotopoulos syndrome (PS).
- To determine if extra-occipital spikes in PS are truly independent or secondary to occipital spikes.
Main Methods:
- Analysis of interictal spike patterns in seven children with PS.
- Visual analysis, spike marking, clustering, waveform averaging, and electrode space mapping.
- Assessment of spike propagation patterns (focal, spreading, or independent).
Main Results:
- Interictal spike patterns in PS were not stereotypical, even in the occipital lobe.
- Some spikes remained focal or showed limited spread.
- Other spikes propagated between anterior and posterior brain regions, indicating multifocal origins.
Conclusions:
- In Panayiotopoulos syndrome, all cerebral locations can independently generate and propagate interictal spikes.
- PS is confirmed as a multifocal epileptic syndrome.
- This finding expands the anatomical definition of focal epilepsy phenotypes.
Objective:
To investigate the spatiotemporal course of interictal spikes in Panayiotopoulos syndrome (PS), and in particular whether seemingly independent extra-occipital spikes are truly autonomous or secondary, triggered by occipital spikes.
Methods:
Seven children with the most representative interictal spike patterns on visual analysis were studied. Five had a single focus (occipital in two, suggestive of posterior to anterior spike propagation in two, and frontal) and two had two foci over the posterior and the anterior areas independently. Spikes were marked, clustered and waveform - averaged, and mapped on electrode space.
Results:
The patterns of spatial and temporal dynamics of the interictal spikes were not stereotypical for any brain area, including the occipital lobe. Some of the anterior and the posterior spikes remained focal or showed little spread, but others appeared to propagate to the opposite direction (occipital to frontal and vice versa).
Conclusions:
In PS all cerebral locations are able to spontaneously and independently generate and propagate interictal spikes, indicating that PS is a multifocal epileptic syndrome.
Significance:
Confirmation of the multifocal character of PS improves clinical diagnosis and challenges our current taxonomic concepts by expanding the anatomical boundaries of a distinct focal epilepsy phenotype from lobar to system.
