166 Post Market Rate of Seizures During TMS Treatment with NeuroStar® System Appears to Be Lower than Previously Estimated

Abstract

Abstract:Objective: NeuroStar® Advanced Therapy System is a transcranial magnetic stimulation (TMS) device with FDA-clearance for the treatment of Major Depressive Disorder (MDD) in adult patients who have failed to receive satisfactory improvement from prior antidepressant medication in the current episode. With TMS, magnetic pulses are transmitted into the brain. Though the exact mechanism of action is unknown, it is postulated that resulting neuronal depolarization and changes in brain functional activity may be associated with various physiologic changes that lead to relief of depression in the indicated population. The type of magnetic field generated with TMS is not intended to induce a seizure during therapeutic use, but unintentional seizures have been reported during TMS treatment.No seizures were reported with the use of the NeuroStar® system in clinical trials conducted prior to FDA clearance. The estimated risk of seizure in the NeuroStar® label is approximately 1 in 30,000 treatments or 1 in 1,000 patients. Since introduction of the NeuroStar® system into clinical practice, the rate at which seizures have been reported is even lower.Methods:We conducted a review of literature that named the NeuroStar® Advanced Therapy System as the device used for TMS treatment and reviewed all seizure events reported to Neuronetics, Inc., directly or through FDA MedWatch through June 30, 2019. Articles reporting seizures in subjects with epilepsy during TMS treatment were excluded.Results:Previous comprehensive reviews of seizures induced by treatment with any TMS device by Wasserman et al. (1998) and Rossi et al. (2009) revealed that the rate of seizures is low. Many subjects that developed seizures during TMS had either received stimulation at parameters beyond current recommendations or had been predisposed to develop seizures in some way. Some of the events reported as seizures may, in fact, have been non-epileptic events.Our literature review and analysis of seizures reported to Neuronetics, Inc. revealed that the rate of seizures during TMS treatment with the NeuroStar® appears to be lower than the rate that is published in the NeuroStar® Advanced Therapy prescribing information.Conclusions:Seizures that take place during TMS treatment with the NeuroStar® system are rare. The rate of seizures reported directly to Neuronetics, Inc. is lower than that included in the NeuroStar® prescribing information. Our literature review validated seizures during TMS treatment with the NeuroStar® system reported in published literature have described either non-epileptic events (syncope) or occurred with risk factors for seizure induction, such as other predisposing clinical factors or treatment parameters outside the guideline recommend “safe” ranges.Funding Acknowledgements:Neuronetics, Inc.

Theta burst transcranial magnetic stimulation to induce seizures in an epilepsy monitoring unit

“…However, that approach is likely to induce seizures that have different origins and characteristics compared to the patients' spontaneous seizures. Accordingly, we used protocols that are being routinely used in plasticity [9] and treatment regimens [11,15]. These TBS protocols appear to be safe in epilepsy patients, consistent with published TMS safety reviews in epilepsy [19].…”

“…Another non-invasive method, transcranial magnetic stimulation (TMS), can be used to increase cortical excitability [9] and thus could potentially be used to purposefully induce seizures in patients with epilepsy, although TMS has not been studied for this purpose. By increasing cortical excitability, TMS could trigger seizures in an epileptic focus [10,11]. High frequency bursts of TMS known as theta burst stimulation (TBS) are known to alter cortical excitability in such a way that continuous TBS (cTBS) decreases cortical excitability whereas intermittent TBS (iTBS) increases cortical excitability [12].…”

“…There are many reports of accidental seizure induction in healthy subjects as well as in epilepsy patients using single or patterned stimuli [10,11,13e15]. Some of these cases may have been related to stimulation parameters exceeding safety guidelines [15], biological predisposition to seizures, or non-epileptic events such as syncope or psychogenic seizures [11].…”