Closed-Loop Deep Brain Stimulation Using a Type of Fixed-Time Sliding Mode Controller for Avoiding Epileptiform Discharge in a Human Cortical Model

Abstract

The cortical excitability rate correlates with epileptic seizures, which should be modulated in a finite time to prevent brain damage. Deep brain stimulation (DBS) is a successful treatment for patients with refractory epilepsy. This study proposes a closed-loop DBS control method that uses a Fixed-Time Integral Super-Twisting Sliding Mode Controller (FTISTSMC) to stop simulated epileptiform discharges within a limited time by modifying cortical excitability in the human Cortical Model (CM). First, the simulated stimulus current in the DBS method is injected into the state variable of the excitatory neurons population in CM. Then, the FTISTSMC is applied to the state variable described above to regulate the stimulus current value during the stimulation process to reduce the possible destructive effects of electrical pulses on the behavior of the healthy neurons. The proposed controller has some characteristics causing the simulated epileptic activity to become normal and the tracking error of the healthy state to be completely zero after 4.7[Formula: see text]s. In addition, it is possible to resolve the chattering and singularity problems and completely control epileptic seizures within a fixed and finite time frame.