6.6. Magnetic resonance imaging

In the present study hippocampal sclerosis was found in eight patients. The volumes of the hippocampus and the amygdala were smaller in patients with hippocampal sclerosis compared to the patients without hippocampal sclerosis, but the difference did not reach statistical significance. Slightly decreased hippocampal and amygdaloid volumes were detected with a long duration of TLE.

Based on the results of this study, the volumes of the hippocampi and amygdalas may decrease with the duration of epilepsy. The etiology and pathogenesis of structural damage in the medial temporal lobe of patients with epilepsy has been a matter of controversy for years. It is known that structural damage in the hippocampus precedes the appearance of TLE in many patients but not all cases with hippocampal sclerosis have a history of initial insult. On the other hand, whereas some studies have suggested an association between atrophy of the mesial temporal structures and duration of epilepsy, the others have failed to show this association. (Mathern et al. 2002, Kälviäinen & Salmenperä 2002)

Today it has been concluded that hippocampal sclerosis is probably both the cause and the effect of seizures (Mathern et al. 2002, Kälviäinen & Salmenperä 2002).