Reversible psychiatric adverse effects related to deep brain stimulation of the anterior thalamus in patients with refractory epilepsy

Abstract

Anterior nucleus of thalamus (ANT) deep brain stimulation (DBS) is becoming a more common treatment for drug-resistant epilepsy. Epilepsy and depression display a bidirectional association. Anterior nucleus of thalamus has connections to anterior cingulate cortex and orbitomedial prefrontal cortex, hence, a possible role in emotional and executive functions, and thus, ANT DBS might exert psychiatric adverse effects. Our aim was to evaluate previous and current psychiatric symptoms in patients with epilepsy undergoing ANT DBS surgery and assess the predictability of psychiatric adverse effects. Programming-related psychiatric adverse effects are also reported. Method: Twenty-two patients with ANT DBS for retractable epilepsy were examined, and a psychiatric evaluation of depressive and other psychiatric symptoms was performed with Montgomery and Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI), and Symptom Checklist prior to surgery, concentrating on former and current psychiatric symptoms and medications. The follow-up visit was one year after surgery. Results: At the group level, no changes on mood were observed during ANT DBS treatment. Two patients with former histories of depression experienced sudden depressive symptoms related to DBS programming settings; these were quickly alleviated after changing the stimulation parameters. In addition, two patients with no previous histories of psychosis gradually developed clear paranoid and anxiety symptoms that also relieved slowly after changing the programming settings. Conclusion:The majority of our ANT DBS patients did not experience psychiatric adverse effects. Certain DBS parameters might predispose to sudden depressive or slowly manifesting paranoid symptoms that are reversible via programming changes.

Responsive neurostimulation for regional neocortical epilepsy

“…Recently, thalamic deep brain stimulation (DBS) was approved in the United States for treatment of drug‐resistant focal epilepsy, and RNS targeting thalamic nuclei with diffuse cortical projections has also demonstrated promise for treating large epileptogenic networks . However, these approaches can be complicated by lead misplacement and by side effects intrinsic to stimulating brainstem nuclei, including sleep disruption, neuropsychiatric symptoms, and memory loss . Theoretically, direct cortical stimulation could avoid some of these limitations.…”

Improving the effectiveness of ANT DBS therapy for epilepsy with optimal current targeting

“…In the long‐term phase of the SANTE study, changing stimulation voltage from 5.0 to 7.5 V or frequency from 145 to 185 Hz did not show an effect on the seizure frequency more than initial settings 1 . We described previously patients that developed psychiatric adverse effects associated with ANT DBS programming settings 22 . As new‐onset psychiatric symptoms are a common finding following epilepsy surgical procedures, these symptoms related to ANT DBS can be alleviated by changing the stimulation intensity and different active contacts.…”

“…For the one patient with initially one unilateral contact active in ANT (Patient 5) who refused suggested reimplantation, the active contacts were changed to the most superior ones by reprogramming and this allowed the volume of activated tissue around the other contact (that itself remained inferior to ANT) to reach ANT. This patient was a responder from the beginning, but the programming changes alleviated the patients’ psychiatric adverse effects 22 …”

“…Firstly, we wanted to assess whether seizure outcomes could be improved by programming changes or reimplantation based on anatomy. We have recently demonstrated the importance of the detailed individualized anatomical knowledge of the stimulated contacts since these determine the probability that a patient will respond favorably 20,21 both in terms of seizure outcomes and in avoiding psychiatric side‐effects 22 . Our second goal for this study was to analyze the effect of ANT DBS on specific seizure types with the emphasis on the impairment of consciousness.…”

Anterior thalamic deep brain stimulation in epilepsy and persistent psychiatric side effects following discontinuation

“…However, in all previously published reports, the PSEs were time-related to stimulation. Järvenpää et al [9] suggested decreasing the voltage or changing the stimulation contacts to suppress PSEs. At the moment, there is no official recommendation for the management of PSEs in patients with ANT-DBS.…”