NEW YORK (Reuters Health) – In patients with focal epilepsies, the evolution of an abdominal aura into an automotor seizure is highly suggestive of temporal lobe epilepsy (TLE), according to a report published in the January 22nd issue of Neurology.
Previous studies have yielded conflicting results regarding the diagnostic significance of abdominal auras. However, none have examined the evolution of these auras into other seizures and whether these patterns can identify where the seizure is originating in the brain.
Knowing the origin of the seizure, temporal versus extratemporal, is important because epilepsy surgery is much more effective in patients with temporal foci. Imaging modalities can help differentiate between the two, but invasive testing is often required.
Dr. Soheyl Noachtar, from the University of Munich in Germany, and colleagues analyzed the seizure patterns of 491 consecutive patients with focal epilepsies. Based on EEG and MRI results, 223 patients had TLE, 113 had extratemporal epilepsies, and 155 had seizures that could not be localized to one lobe.
In agreement with previous reports, abdominal auras were more common among patients with TLE than among those with extratemporal epilepsy (p < 0.0001). Furthermore, these auras were more often found in patients with mesial TLE than in those with neocortical TLE (p = 0.007).
In patients with TLE, at least one abdominal aura evolved into an automotor seizure, the investigators note. In contrast, only two patients in the extratemporal epilepsy group had auras that evolved into automotor seizures.
The presence of abdominal aura was associated with a 73.6% probability of having TLE. However, if the aura evolved into an automotor seizure, the probability rose to 98.3%.
"These results demonstrate that evolution of abdominal aura into automotor seizure permits differentiation between TLE and extratemporal epilepsy, showing that analysis of seizure evolution provides more localizing information than does the frequency of particular seizure types," Dr. Noachtar's team concludes.