Semantic Memory Impairment in Epilepsy

Background: Epilepsy is a common neurological disorder characterized by recurrent seizures due to abnormal neuronal electrical activity. This condition affects approximately 65 million people globally, with around 80% in developing countries. In India, the prevalence ranges from 5.59 to 10 per 1,000 people, with rural areas exhibiting higher rates than urban ones. Epilepsy’s impact on cognitive functions, including semantic memory, is significant but often underexplored. Objective: This study is aimed to assess semantic memory impairment in patients with epilepsy. Methods: This is a cross-sectional analytical study conducted among 250 epilepsy patients attending the neurology department of a tertiary care centre. The sample was derived based on statistical calculations to ensure sufficient power and accuracy. Inclusion criteria were patients aged over 18 with a diagnosis of epilepsy, while those with intellectual disabilities or neurodegenerative disorders were excluded. Data collection included seizure onset age, seizure semiology, epilepsy duration, antiepileptic drug (AED) use, and MRI and EEG results. Semantic memory was evaluated using the Indian Semantic Memory Test Battery, encompassing naming tests, word-picture matching, and sorting tasks. Statistical analysis involved multivariate regression to examine relationships between cognitive scores and clinical variables. Results: Among the 250 participants, 147 (59%) had generalized epilepsy and 103 (41%) had focal epilepsy. Sociodemographic factors, clinical profiles, and memory test scores were analyzed. Significant findings included higher rates of MRI abnormalities and EEG changes in focal epilepsy. Semantic memory deficits were evident across all categories. For instance, 10% of generalized epilepsy and 12% of focal epilepsy patients scored below 50% in total naming scores. Additionally, significant impairments were observed in word-picture matching and sorting tasks, with overall percentages ranging from 11% to 25.3% for various test levels. Conclusion: The study highlights that semantic memory impairment in epilepsy extend beyond episodic memory issues, affecting the semantic-verbal system and influencing both memory and language performance. These findings underscore the need for a deeper understanding of semantic processing challenges in epilepsy, which could improve patient care and support. Differentiating between semantic-verbal system impairment and episodic memory deficit is crucial for developing effective therapeutic strategies.