Related Experiment Video
Updated: Mar 19, 2026
Evaluation of Hemisphere Lateralization with Bilateral Local Field Potential Recording in Secondary Motor Cortex of Mice
Published on: July 31, 2019
How Different Are the Patients With Bilateral Hippocampal Sclerosis From the Unilateral Ones Clinically?
Ebru Nur Vanli-Yavuz1,2, Betul Baykan1, Serra Sencer3
11 Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
Insights
Bilateral hippocampal sclerosis (BHS) in epilepsy patients presents distinct features compared to unilateral cases. BHS is associated with higher rates of intellectual disability, psychosis, and certain seizure types, though some cases show a benign course.
Area of Science:
- Neurology
- Epileptology
- Neuroimaging
Background:
- Epilepsy is a neurological disorder characterized by recurrent seizures.
- Hippocampal sclerosis (HS) is a common cause of epilepsy, particularly in adults.
- Bilateral hippocampal sclerosis (BHS) is less understood than unilateral HS (UHS).
Purpose of the Study:
- To identify and compare the differentiating clinical, EEG, and neuroimaging features of epilepsy associated with bilateral hippocampal sclerosis (BHS) versus unilateral hippocampal sclerosis (UHS).
Main Methods:
- Retrospective analysis of epilepsy patients with MRI-defined BHS.
- Inclusion of UHS patients as a control group.
- Comparison of clinical data, EEG findings, treatment response, and surgical outcomes.
Main Results:
- 124 patients included: 31 BHS and 93 UHS.
- BHS group showed significantly higher frequencies of febrile status epilepticus, mental retardation, status epilepticus, and psychosis.
- EEG background slowing was more frequent in BHS.
- 16.1% of BHS and 18.3% of UHS were not drug-refractory.
- 66.67% of operated BHS patients benefited from surgery.
Conclusions:
- BHS represents a heterogeneous epilepsy group with distinct clinical and EEG characteristics compared to UHS.
- Increased prevalence of intellectual disability, status epilepticus, and psychosis are key differentiators for BHS.
- A subset of BHS patients exhibits a benign course, and epilepsy surgery can be beneficial for some drug-resistant cases.
Purpose:
There is a lack of knowledge on consecutive patients with epilepsy associated with bilateral hippocampal sclerosis (BHS). We aimed to investigate the differentiating features of BHS in comparison with unilateral HS (UHS).
Method:
We investigated our database for patients with epilepsy fulfilling the major magnetic resonance imaging criteria for BHS; namely, presence of bilateral atrophy and high signal changes on T2 and FLAIR series in the hippocampi. UHS patients seen in past 2 years were included as the control group. Clinical, EEG, and other laboratory findings, data on treatment response and epilepsy surgery were investigated from their files.
Results:
A total of 124 patients (31 with BHS and 93 with UHS; 49 right-sided and 44 left-sided) were included. We found that 16.1% of the BHS and 18.3% of the UHS groups were not drug-refractory. A binary logistic regression analysis performed with significant clinical features disclosed that history of febrile status epilepticus, mental retardation, and status epilepticus were statistically more common in BHS group. Moreover, diagnosis of psychosis established by an experienced psychiatrist and slowing of the EEG background activity were both found significantly more frequent in BHS. 66.67% of the operated BHS patients showed benefit from epilepsy surgery.
Conclusions:
BHS is a heterogeneous group, showing significant differences such as increased frequencies of mental retardation, status epilepticus, febrile status epilepticus and psychosis, in comparison to UHS. In all, 16.1% of the BHS cases showed a benign course similar to the UHS group and some patients with drug-resistant epilepsy may show benefit from epilepsy surgery.
More Related Videos
Related Concept Videos
01:19Role of Hippocampus in Memory
01:28Lateralization