Clinical and neuroimaging features of good and poor seizure control patients with mesial temporal lobe epilepsy and hippocampal atrophy.

Purpose: Hippocampal atrophy (HA) and signal changes, detected at magnetic resonance imaging, have been associated with intractable seizures. Such a relation has been established by tertiary centers, where the prevalence of more severe cases tends to be higher. We evaluated the clinical and imaging variables that may have relevance to seizure control in patients with mesial temporal lobe epilepsy (MTLE) and HA.

Methods: MTLE patients from the outpatient clinic of University of São Paulo School of Medicine at Ribeirão Preto were evaluated with protocols for the temporal lobe. Patients were considered to have good seizure control (GC; n = 42) if they had three of fewer seizures per year. Patients with pharmacoresistance and who did not fit the criteria for GC were considered to have poor seizure control (PC; n = 44). We made group comparisons and correlations of clinical data and hippocampal volume (HV) with seizure frequency.

Results: No statistical differences were observed between the GC and PC groups in the following parameters: age at the time of study, age at the time of the initial precipitating injury (IPI) or first epileptic seizure, epilepsy duration and follow-up, and family history of epilepsy. No differences were found in HV between GC (male, 2.04 +/- 0.60 cc; female, 2.00 +/- 0.70 cc) and PC (male, 2.26 +/- 0.47 cc; female, 2.15 +/- 0.48 cc) groups. Regression analysis indicated no correlation between seizure frequency and HV (p = 0.33).

Conclusions: These findings suggest that the intensity of HA does not have a direct correlation with seizure frequency in patients with MTLE with HA and that the detection of HA in MTLE patients does not mean an unequivocal indication of intractability.