High performance seizure-monitoring system using a vibration sensor and videotape recording: behavioral analysis of...

A new seizure-monitoring apparatus containing a piezoceramic vibration sensor combined with videotape recording was developed. Behavioral analysis of Ihara's genetically epileptic rat (IGER), which is a recently developed novel mutant with spontaneously limbic-like seizures, was performed using this new device. Twenty 8-month-old male IGERs were monitored continuously for 72 h. Abnormal behaviors were detected by use of a vibration recorder, and epileptic seizures were confirmed by videotape recordings taken synchronously with vibration recording. Representative forms of seizures were generalized convulsions and circling seizures. Generalized convulsions were found in 13 rats, and circling seizures in 7 of 20 animals. Two rats had generalized and circling seizures, and two rats did not have seizures. Although there was no apparent circadian rhythm to the generalized seizures, circling seizures occurred mostly between 1800 and 0800 h. A correlation between the sleep-wake cycle and the occurrence of circling seizures seems likely. Without exception, all the seizure actions were recorded by the vibration recorder and the videotape recorder. To eliminate the risk of a false-negative result, investigators scrutinized the information obtained from the vibration sensor and the videotape recorder. The newly developed seizure-monitoring system was found to facilitate detailed analysis of epileptic seizures in rats.