Reduced total number of enlarged perivascular spaces in post-traumatic epilepsy patients with unilateral lesions - a feasibility study

Enlarged perivascular space in the temporal lobe as a prognostic marker in temporal lobe epilepsy with hippocampal sclerosis

OBJECTIVE

This study was undertaken to investigate the regional burden of enlarged perivascular spaces (EPVSs) in patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) and explore its prognostic relevance.

METHODS

In this retrospective observational study, EPVSs in the temporal lobe (T-EPVS), centrum semiovale (CS-EPVS), basal ganglia (BG-EPVS), midbrain, and hippocampus were visually rated in 68 treatment-naïve patients with TLE-HS. Regional EPVS burden was dichotomized into high and low degrees (cutoff: >10 for BG-EPVS/T-EPVS; >20 for CS-EPVS). Cox proportional hazards models were used to determine the potential predictors of seizure freedom (SF; no seizure for >1 year) and delayed SF (SF achieved >6 months after initiating antiseizure medication [ASM]). Multivariate logistic regression using stepwise variable selection based on the Akaike information criterion was performed to investigate whether EPVS burden was associated with medical refractoriness (never achieving SF).

RESULTS

Of the 68 patients, 20 were classified into the refractory group (29.4%). The high T-EPVS group had an older epilepsy onset (37.3 ± 12.3 vs. 26.5 ± 13.0 years, p = .005), higher pretreatment seizure density (median = 12.0, interquartile range [IQR] = 5.0-20.0 vs. 4.0, IQR = 2.0-10.5, p = .008), and lower focal to bilateral tonic-clonic seizure prevalence (13.3% vs. 73.6%, p < .001) than the low T-EPVS group. High T-EPVS burden (odds ratio [OR] = 10.908, 95% confidence interval [CI] = 1.895-62.789) was an independent predictor of medial refractoriness, along with female sex (OR = 12.906, 95% CI = 2.214-75.220) and ASM treatment duration (OR = .985, 95% CI = .971-.999). The low T-EPVS group had higher probability of achieving delayed SF than the high T-EPVS group (pLog-rank = .030, pCox regression = .038), whereas the probability of achieving SF was comparable between the two groups (pLog-rank = .053, pCox regression = .146).

SIGNIFICANCE

Increased T-EPVS burden may serve as an imaging marker of unfavorable prognosis in patients with TLE-HS, underscoring the potential role of perivascular dysfunction in diminished ASM response.

Bilateral glymphatic dysfunction and its association with disease duration in unilateral temporal lobe epilepsy patients with hippocampal sclerosis

OBJECTIVE

In this study, the diffusion tensor imaging along perivascular space analysis (DTI-ALPS) technique was utilized to evaluate the functional changes in the glymphatic system of the bilateral hemispheres in patients with unilateral temporal lobe epilepsy (TLE) accompanied by hippocampal sclerosis (HS). The aim was to gain insights into the alterations in the glymphatic system function in TLE patients.

METHODS

A total of 61 unilateral TLE patients with HS and 53 healthy controls (HCs) from the Department of Neurosurgery at Xiangya Hospital were included in the study. All subjects underwent DTI using the same 3 T MR Scanner, and the DTI-ALPS index was calculated. Differences in the DTI-ALPS index between TLE patients and HCs were evaluated, along with the correlation between the DTI-ALPS index of TLE and clinical features of epilepsy. These features included age, age of onset, seizure duration, and neuropsychological scores.

RESULTS

Compared to the bilateral means of the HCs, both the ipsilateral and contralateral DTI-ALPS index of the TLE patients were significantly decreased (TLE ipsilateral 1.41 ± 0.172 vs. HC bilateral mean: 1.49 ± 0.116, p = 0.006; TLE contralateral: 1.42 ± 0.158 vs. HC bilateral mean: 1.49 ± 0.116, p = 0.015). The ipsilateral DTI-ALPS index in TLE patients showed a significant negative correlation with disease duration (r = -0.352, p = 0.005).

CONCLUSIONS

The present study suggests the presence of bilateral dysfunctions in the glymphatic system and also highlight a laterality feature in these dysfunctions. Additionally, the study found a significant negative correlation between the ipsilateral DTI-ALPS index and disease duration, underscoring the significance of early effective interventions and indicating potential for the development of innovative treatments targeting the glymphatic system.