Within a day, transcranial direct current stimulation (tDCS) applied to the scalp over a seizure focus improved spikes and electrographic seizure frequency in patients with super-refractory focal status epilepticus, according to the findings of a small study published in the journal Epilepsia.
The use of tDCS has been endorsed for a variety of psychiatric and neurologic disorders, including epilepsy. A 1- to 4-mA cathodal current applied to the scalp over a seizure focus is associated with a reduction in spikes and seizures. “Very limited experience is available with the use of tDCS for focal status epilepticus,” researchers acknowledged.
The researchers conducted a case series that included 4 patients (3 women, 1 man; age, 34-68; 3 had preexisting seizures) with focal status epilepticus in the intensive care unit (ICU) in whom symptoms did not resolve with the use of conventional antiseizure medications and anesthetics. All 4 individuals were referred for tDCS.
A battery-powered cathodal current at 2 mA was delivered by an ActivaDose (Caputron) tDCS device with a saline-soaked sponge on the scalp over the area of seizure focus. The anode was placed on the contralateral forehead or shoulder. Treatment lasted for 30 minutes, was repeated twice daily, and then was repeated again 1-4 times more over the next several days.
Over the study period, patient 1 and patient 4 experienced lateralized periodic discharges (LPDs), whereas patient 2 and patient 3 experienced both LPDs and electrographic evolving seizures. At the time they received their initial tDCS treatment, the participants were experiencing electrographic seizures or LPDs, but no visible behavioral seizures because of the inhibitory actions of antiseizure medications or anesthetics.
In the 4 participants, etiologies of status epilepticus included posterior reversible encephalopathy syndrome (PRES) in association with immunosuppression for a liver transplantation, perinatal hypoxic-ischemic injury, a previous cardioembolic parietal stroke, and central nervous system lupus.
The use of tDCS was associated with a significant reduction in interictal spikes (from 0.78 per second to 0.38 per second; P <.0001) in 3 participants and electrographic seizures (from 3.83 per hour to 0 per hour; P <.001) in 2 participants.
Use of tDCS was linked to medication reductions in all 4 patients. The only adverse effect of tDCS reported was transient erythema beneath the sponge in 1 participant. Two of the patients died of causes that were not associated with tDCS, 1 patient was discharged to a nursing home, and 1 patient became fully responsive with all seizures controlled with tDCS.
The interpretation of the results is limited by uncertainty surrounding the role played by tDCS among rapidly changing medications and clinical situations in the ICU, including resolution of PRES in 1 participant. Further, the current case series lacks placebos, controls, randomization, or blinding. Since all patients were suppressed by anesthesia to levels of burst suppression, this rendered it impossible to evaluate clinical seizures prior to and following tDCS treatment.
“Given these limitations, our findings are intriguing and worthy of controlled study, but they are not conclusive,” the researchers noted.
They concluded, “TDCS may be a feasible and well-tolerated non-invasive neuromodulatory approach for treating focal status epilepticus or clinically relevant lateralized periodic discharges in the critical care setting.”
Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Fisher RC, McGinn RJ, Von Stein EL, et al. Transcranial direct current stimulation for focal status epilepticus or lateralized periodic discharges in four patients in a critical care setting. Epilepsia. Published online January 20, 2023. doi:10.1111/epi.17514