Integrity of cognitive functions in trigeminal nerve stimulation trials in neuropsychiatry.

It is common for both practitioners and patients to have concerns about the possible neurocognitive side effects of neuromodulation techniques and these may also be related to poor adherence.1 Electroconvulsive therapy (ECT) is currently considered the most effective treatment for severe depression. However, effects such as anterograde and retrograde amnesia and impairment of orientation, processing speed, attention, verbal fluency, and executive functions have been reported after ECT sessions.1 Clinical trials investigating neuropsychological outcomes after neuromodulation strategies therefore tend to focus on cognitive safety. Trigeminal nerve stimulation (TNS) is a transcutaneous neuromodulation technique based on the “bottom-up mechanism” in which alternating electric current is administered over the supraorbitary branch of the trigeminal nerve and stimuli propagate towards brain areas related to symptoms of depression and anxiety, modulating their activities. The efficacy of TNS for major depressive disorder has been studied and the results are interesting.2,3 However, investigations are still ongoing into safety issues related to TNS, such as compromise to skin integrity.4 We present an exploratory analysis of cognitive assessments conducted in clinical trials undertaken by our neuromodulation group. As part of clinical trials performed to investigate the efficacy of TNS for neuropsychiatric disorders such as depression, generalized anxiety, fibromyalgia, panic disorder, posttraumatic stress disorder5 and obsessivecompulsive disorder, 64 patients have been evaluated for cognitive function before and after a TNS protocol, using the Montreal Cognitive Assessment (MOCA). The TNS protocol used was as proposed by Shiozawa et al.3 and involves using an external neurostimulator to deliver an electric current with a frequency of 120 Hz and a pulse duration of 200 ms for 30 minutes. Intensity is Integridade das funções cognitivas em ensaios clínicos de estimulação do nervo trigêmeo em neuropsiquiatria