Neurostimulation

Neurostimulation refers to medical techniques that deliver electrical or magnetic energy to the nervous system in order to modulate neural activity for therapeutic purposes. The goal is to influence neural excitability, synaptic transmission, and brain or nerve network function to alleviate symptoms, improve function, or slow disease progression. Neurostimulation encompasses both invasive and noninvasive approaches.

Invasive modalities involve implanted devices that deliver electrical stimulation to specific neural structures. Deep brain stimulation (DBS) uses implanted electrodes and a pulse generator to target deep brain nuclei and is used for movement disorders such as Parkinson’s disease, essential tremor, and dystonia, as well as emerging indications in epilepsy and depression. Spinal cord stimulation (SCS) delivers currents to the dorsal columns to reduce chronic neuropathic or ischemic pain. Vagus nerve stimulation (VNS) applies stimulation to the vagus nerve via an implanted device, with indications including refractory epilepsy and treatment-resistant depression. Other invasive targets include peripheral or cranial nerves and motor cortex stimulation for various pain and seizure disorders.

Noninvasive modalities do not require implanted hardware. Transcranial magnetic stimulation (TMS) uses magnetic fields to induce electric currents in cortical tissue and is approved for certain mood disorders, with research across a range of conditions. Transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) apply weak currents through the scalp to modulate cortical excitability. Peripheral nerve stimulation and other forms are used in chronic pain and rehabilitation settings.

Safety, efficacy, and patient selection vary by modality and condition. Common risks include infection or hardware issues with implants, seizure risk with TMS, and skin irritation or discomfort with noninvasive methods.