Arabic verbal fluency in mesial temporal and generalized epilepsy: evidence from letter and category tasks with...

Mesial temporal lobe epilepsy (MTLE) is the most common focal epilepsy, frequently associated with hippocampal sclerosis and cognitive dysfunction extending beyond episodic memory. Verbal fluency, a multidomain task integrating executive and temporal-semantic processes, is particularly sensitive to temporal pathology. This study examined Arabic letter and category fluency in patients with MTLE, generalized epilepsy (GE), and healthy controls (HC), with a focus on semantic categories differing in episodic content.

A cross-sectional study was conducted at King Saud University Medical City. Participants (N = 135; age 18-59) completed four Arabic letter fluency tasks (Ain, Sheen, Qaf, Dal) and three category tasks (countries, fruits, four-legged animals). Among the participants, 43 had MTLE, 45 had GE, and 47 were HC. Assessments were conducted remotely via telephone using standardized administration procedures. Quantitative measures (total words, z-scores) and qualitative indices (clustering, switching, perseverations, intrusions) were analyzed. Multiple linear regressions controlled for age, sex, education, epilepsy type, and antiseizure medication (ASM) burden.

Both epilepsy groups produced significantly fewer words than HC for total phonemic but not total semantic fluency. The "countries" category however, classified as episodically enriched, was selectively impaired in MTLE (p = 0.034), while static categories (fruits, four-legged animals) were preserved. MTLE participants exhibited markedly more perseverations across all semantic categories and increased intrusions exclusively in "countries." Fluency performance declined across time intervals in all groups. Polytherapy with ≥3 ASMs predicted lower fluency scores, whereas laterality of MTLE did not.

MTLE selectively disrupts episodically enriched semantic fluency, supporting a hippocampal role in binding episodic and semantic memory. These findings highlight the diagnostic potential of category-specific fluency-such as "countries"-as a marker of hippocampal dysfunction and underscore the value of culturally adapted Arabic fluency norms.