Transcranial direct current stimulation treatment reduces, while repetitive transcranial magnetic stimulation treatment increases electroencephalography spike rates with refractory occipital lobe epilepsy: A case study

Objective

Non-invasive brain stimulation has been suggested as an alternative/supplementary treatment for focal, refractory epilepsy. However, there are only a few studies and even fewer that directly compared transcranial direct current stimulation (tDCS) to repetitive transcranial magnetic stimulation (rTMS).

Methods

We report the case of a 20-year-old female patient with persistent epileptiform discharges in the left occipital region consistent with focal status epilepticus. The patient received 20 min sessions of tDCS (2 mA) for five consecutive days, with the cathode over the left occipital region and the anode over the contralateral prefrontal lobe. After initial improvement, the patient's condition worsened again, and thus it was decided to treat her with rTMS (1 Hz, 1800 pulses), also for five consecutive days. Before and after each treatment, spike frequency was recorded with electroencephalography (EEG).

Results

There was a significant decrease in spike frequency from pre- to post-tDCS treatment. Depending on the type of data analysis, there was either a near significant (p = 0.058, d = 0.51) or a significant (p < 0.001, d = 1.13) increase from pre- to post-rTMS treatment, and the patient reported a worsening of symptoms.

Significance

The study adds to a growing body of evidence on non-invasive brain stimulation treatments in focal refractory epilepsy. On the one hand, we corroborate its usefulness. On the other hand, we highlight that non-invasive brain stimulation might inadvertently worsen symptoms. Future research needs to determine which method, with which parameters, for which patient is beneficial (and detrimental).

Plain Language Summary

The study details the case of a patient suffering from epilepsy, located in the occipital region of the brain, who did not respond to several antiseizure medications. We treated with both transcranial direct current stimulation and repetitive transcranial magnetic stimulation. The transcranial direct current stimulation treatment resulted in a significant decrease in EEG spikes, yet the patient's condition worsened again after 2 weeks. We therefore used repetitive transcranial magnetic stimulation treatment, which, in fact, resulted in an increase in spike frequency. The results demonstrate both the potential benefits and risks of non-invasive brain stimulation as treatment in drug-resistant epilepsy.