**5. Conclusions**

The use of telemetry to record biopotentials like the EEG during long periods is fundamental to study the role of brain damage in epileptogenesis. Our group (de Araujo Furtado *et al*., 2010) found and quantified SRS in rats exposed to the nerve agent soman, several days postexposure. White and co-workers (2010) investigated the occurrence of spontaneous seizures in the kainate model through the use of a commercially available telemetry system (DSI). They were able to identify spikes and spike clusters, which occurred after the initial, prolonged seizure, but preceded the first spontaneous seizure, thus finding clues about the development of chronic epilepsy using the EEG as a powerful biomarker. An EEG telemetry system can allow the investigation of a phenomenon that without continuous monitoring would never be accurately studied. Still, one must be careful about the interpretation of results because the number of EEG channels limits the identification of the epileptic focus.

The identification and characterization of SRS, that occur after acute seizures induced by soman, emphasize the importance of quantifying SRS in studies where the objective is to find new therapeutics against soman-provoked seizures. It is known that exposure to soman can cause acute and chronic damage (Petras, 1994; Shih *et al*., 2003), therefore, an ideal evaluation model must assess the neuroprotective effect of the therapeutic agent with both short-term and long-term EEG monitoring. However, it is very common to monitor the EEG for a time period of only 1–2 days post-exposure in the field of nerve agent studies. Obviously, this period is not enough to detect SRS and long-term morphological changes. Optimally, one should study the EEG changes over a period of several months (limited by the battery life of telemetry devices).

Among the limitations of telemetry, battery life is probably one of the most important. Also, an implantable telemetry system must be miniaturized in a way that the subject is not disturbed. Sealing of the transmitter plays a role, because if sealing is compromised it can ruin the device and consequentially the experiment. Several new technologies may address these limitations. New approaches that allow battery integration with the circuit/electrodes and the use of rechargeable batteries may be a great advantage (Budgett *et al*., 2007). The lack of spatial resolution that is inherent in the EEG could be compensated by the use of arrays of multiple electrodes and the use of Bluetooth technology. Rechargeable batteries could permit one to run very long-term experiments (perhaps 1-2 years), studying epileptogenesis not only in animals that display acute seizures, but also on those that do not exhibit initial status epilepticus. Finally, the use of a semi-automated algorithm is a minimum requirement for data analysis in order to analyze continuous long-term EEG recordings in a time-efficient and accurate manner.
