Authors :
Presenting Author: Thiri Lin, MD, PhD – UNC Health
Angela Wabulya, MD – UNC Health
Guillermo Palomeque, MD, FACNS – Ramon y Cajal Hospital
Valeria Rivero, MD – Ramon y Cajal Hospital
Clio Rubinos, MD, MS, FACNS – University of North Carolina, Chapel Hill, North Carolina, USA.
Rationale:
We present two cases of Ping-Pong seizures, one that it begins in its classical presentation and another one that initiates independently in both hemispheres, generated cyclic seizures and ultimately Bilateral Independent Status Epilepticus (BISE):
Methods: N/A
Results:
- 28-year-old post–cardiac arrest patient: EEG revealed bursts of asynchronous and synchronous slow and sharp waves of high voltage, over both hemispheres. These critical events consisting of discharges recruiting theta activity that evolves into degraded delta with interspersed spikes of one hemisphere which ends with periodic short interval discharges until termination. Occurring continuously and independently in both hemispheres, on occasions overlapping the end of the seizure in one hemisphere with the beginning of the contra lateral one, consistent with Ping-Pong seizures.
- 42-year-old man with post traumatic epilepsy: Experienced breakthrough seizures. EEG revealed bilateral independent temporal lateralized periodic discharges and bilateral independent bilateral independent rhythmic delta and periodic discharges (BIRDs), progressing cyclically to bilateral temporal BISE that at times seizure overlap to a ping pong pattern.
Conclusions:
Classical ping-pong seizures typically involve a single seizure focus transferring epileptic activity to the contralateral hemisphere, with the original focus ceasing activity once the contralateral activation begins. Our cases illustrate distinct EEG presentations: one patient with hypoxic brain injury demonstrated the classical ping-pong seizure pattern, whereas the second patient showed independent seizure initiation in both hemispheres. The independent bilateral activity suggests separate pacemaker circuits, each with their own refractory periods, which subsequently evolved into BISE. The second case represents an innovative divergence from traditional unilateral propagation mediated by subcortical synchrony, supporting instead a novel pathophysiological model involving thalamocortical network oscillations. Such oscillations may generate synchronized yet independently rhythmic seizure activity through parallel bilateral loops.
Reference:
1. Fisher RS, et al. J Epilepsy 1995;8:29–32. Ping-pong seizures: alternating lateralization in CPS.
Funding: N/A