Rationale:
Deep brain stimulation (DBS) is an evolving treatment modality for epilepsy. DBS has seen use at a number of anatomical sites for treatment of epilepsy, including thalamus, hippocampus, cerebellum, hypothalamus, nucleus accumbens, caudate, medial septal nuclei, subthalamic nucleus, hippocampal commissure, neocortex, and others. Within the thalamus, sites include the anterior nucleus of the thalamus (ANT), centromedian nucleus (CM), dorsalis medialis (DM), and pulvinar. Of these sites, ANT is the best studied and only FDA approved site for DBS to treat epilepsy. DBS targeting CM has also gathered evidence for use in generalized or multifocal seizures. One meta analysis showed mean seizure reduction after stimulation of the CM of 73.4% compared to 60.8% and 67.8% in the ANT and hippocampus respectively.
While DBS has shown significant benefit in reducing seizure frequency, the procedure does have rare complications and side effects. Given significant connectivity between the anterior nucleus of the thalamus and the dorsolateral prefrontal cortex, it is possible stimulation of the ANT, DM, and CM could have an impact on mood and psychiatric symptoms. Sufficient information about psychiatric adverse effects after CM DBS implantation are lacking.
Methods:
This case report follows a 35 year old male with medically refractory localization related epilepsy s/p bilateral CM DBS (2023) bilateral periventricular heterotopia, developmental delay, major neurocognitive disorder, depression, PTSD. The patient underwent epilepsy surgery workup and the data was discordant. The MRI showed extensive L >R periventricular nodular heterotopia. Interictal EEG showed bilateral frontopolar IEDs; ictal EEG showed four left temporal and one right temporal onset seizure. Neuropsych was not lateralizing/localizing. Consensus decision was to offer neuromodulation with DBS with bilateral CM target.Results:
The patient underwent bilateral CM DBS implantation in May 2023 and was followed for 2 years afterwards. He had transient psychiatric symptoms of impulsive and disinhibited behavior which resolved over a year after DBS implantation with optimization of antipsychotics with help of the psychiatrist. He was free of focal to bilateral tonic clonic seizures after the procedure and had ~ 75% reduction in focal seizure with impaired awareness. There were no reported device-related adverse effects after the procedure.
Conclusions:
In summary, this case demonstrates the use of bilateral CM DBS as an effective treatment for localization-related drug-resistant epilepsy when resective surgery would not be feasible or effective. The patient had transient psychiatric symptoms which improved over the course of a year. Funding:
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.