Abstracts

Rationale: The relationship between mesial temporal lobe epilepsy with hippocampal sclerosis and hand dominance has not been yet studied. Based on empirical data and recent literature on the significant reorganization of speech and memory in left-sided MTLE/HS patients, a hypothesis of a significant impact of left-sided MTLE/HS on the organization of motor cortex and handedness was tested. Methods: To investigate hand dominance in subgroups of right- and left-sided MTLE/HS patients, 73 subjects with a definite diagnosis of unilateral MTLE/HS were included in the analysis (31 right and 42 left MTLE/HS; 41 females, 32 males). Hand dominance was assessed in each subject using a standard Edinburgh Handedness Inventory. Results: In the subgroup of left-sided MTLE/HS, 33.3% of the patients were left-handed. In the subgroup of right-sided MTLE/HS, 12% of the patients were left-handed. Subsequent statistical analysis confirmed a significantly higher rate of lefthandedness in subjects with left-sided epilepsy (Fisher P = 0.0399; chi-quadrat = 0.0453). In addition, within the subgroup of left-sided MTLE/HS patients, the age of seizure onset was significantly lower in the group of left-handers than in the group of right-handers (t-test P = 0.032, Mann-Whitney U test P = 0.017). Conclusions: The higher rate of lefthandedness in subjects suffering from left-sided temporal lobe epilepsy as well as the earlier age of seizure onset in the left-handers obviously support our hypothesis of a clinically important impact of the disease on the organization of the motor cortex. Theoretically, the spread of epileptic activity from the epileptic focus to the frontal lobe in the early childhood might produce a “pathological lefthander”. The study was supported by MŠMT ČR Research Program no. MSM0021622404.