Abstracts

Rationale: Intraparenchymal hemorrhage (IPH) is a known complication of stereo-EEG (sEEG); however, there is limited understanding of whether its presence is associated with specific ictal manifestations. The aim of this study was to explore ictal patterns and seizures seen in sEEG that may be suggestive of an established IPH.


Methods: This retrospective study evaluated patients who underwent sEEG between December 2008 to January 2024 at Northwestern’s Comprehensive Epilepsy Center. The presence of IPH and associated sEEG leads were identified through medical records and the co-registration of post-implantation and post explantation CT imaging studies. Each IPH was divided into 2 categories: punctate (bleeds occurring along the sEEG lead trajectory) or volume (bleeds involving 3-dimensional volume in the parenchyma adjacent to the sEEG leads). The sEEG ictal findings investigated were subclinical focal patterns (SFP), electrographic seizures (ES), atypical clinical seizures (ACS), and status epilepticus (SE).


Results: There were total of 87 patients who underwent sEEG implantation. We analyzed 54 patients who had IPH in their post explantation CT of which 27 (50%) were men, of mean age 33 years at the time of sEEG. Twelve patients (22.2%) had prior neurosurgery, 28 (51.9%) patients had implantation on the left hemisphere, and the average number of electrodes per sEEG was 11.2. There were 49 patients who had punctate IPH who had one or more of the ictal patterns or seizures (SFP: 10 (20.4%); ES:29 (59.2%); ACS:2 (4.7%); SE:9 (18.4%)). There were 30 patients with volume IPH who had one or more of the ictal patterns or seizures (SFP: 7 (23.3%); ES:20 (66.7%); ACS:2 (7.4%); SE:8 (26.7%)).

We found a significant association between the presence of volume IPH and the manifestation of status epilepticus (p=0.034). The median SE duration was 16 minutes (min: 7; max 540). There were no significant associations found between the presence of punctate IPH and any of the ictal patterns (SFP: p=0.57; ES: p=0.64; ACS: p=1.0; SE: p=0.58). Additionally, no significant association was found between presence of volume IPH and subclinical focal patterns, electrographic seizures, atypical clinical seizures (SFP: p=0.48; ES: p=0.12; ACS: p=0.5).


Conclusions: Our study shows that status epilepticus is an ictal pattern significantly associated with the presence of volume IPH in patients who had undergone sEEG. In contrast, the presence of punctate IPH was not strongly associated with the manifestation of specific ictal patterns.


Funding: none