Gray matter volume associations with clinical outcomes in epilepsy: A regional cohort study
Klara Andersson1, Marit Boxum2, Meera Srikrishna3
1Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Neurology, Sahlgrenska University Hospital, Region Västra Götaland, member of ERN Epicare, Gothenburg, Sweden; Wallenberg Center of Molecular and Translational Medicine, Gothenburg University, Sweden.
Background:
Regional gray matter volume (GMV) reductions have been observed across epilepsy syndromes. This study aimed to investigate the association between global GMV and clinical outcomes in a regional cohort of adults with epilepsy.
Method:
A cross-sectional analysis of a regional cohort study (PREDICT, clinicaltrials.gov, NCT04559919) was performed. Adults with epilepsy were recruited from five neurology outpatient clinics. Clinical data were collected from patient records and patient-report questionnaires. The latest MRI including T1 sequence was selected per participant and segmented using SPM 12 for MATLAB. GMV and whole brain volume (WBV) were analyzed across groups with seizures or seizure-freedom using logistic regression models adjusting for age, epilepsy duration and total intracranial volume (ICV). Clinical associations with global GMV were analyzed in MRI negative patients using multiple linear regression.
Results:
In the total cohort of 171 participants, median (IQR) age at MRI was 36 (27) years, and epileptogenic lesions on MRI were observed in n (%) = 59 (34.5). The GMV and WBV (cm3) were normally distributed with mean (SD) of 745.9 (104.2) and 1192.8(161.5), respectively. No difference was observed between patients with active epilepsy compared to seizure-free patients in total GMV (mean (SD)) 744.5 (97.3) versus 740.8 (115.7) cm3, p = 0.60), or WBV (1191.9 (154.7) versus 1193.7), p = 0.30). Patients with polypharmacy (≥3 ASM) (n (%)= 46 (26.9)) had lower GMV compared to patients with only 1-2 ASM, (n (%)= 125 (73.1), (mean (SD) 720.983 (88.208) versus 755.097 (108.410), p = 0.04). In MRI negative patients (n = 106), longer epilepsy duration (years) was associated with greater GMV volume (1.32, 95%CI 0.00-2.63, p = 0.05).
Conclusions:
Global GMV and/or WBV were not associated with seizures, suggesting that not all patients with active epilepsy will develop generalized gray matter atrophy. Polypharmacy and late-onset epilepsy were associated with lower GMV, suggesting neurodegeneration related to epilepsy also in a regional cohort study.
