Describe the role of non-invasive neuromodulation in headache disorders.
Non-invasive neuromodulation (NIN) refers to the modulation of neural activity using external devices without surgical implantation. In headache disorders, NIN techniques aim to alter pain pathways and cortical excitability to reduce headache frequency and severity (Bradley's Neurology in Clinical Practice, 8e, Ch. 94).
Headache disorders involve dysregulation of nociceptive pathways, including trigeminovascular activation, cortical spreading depression, and central sensitization. NIN modulates these pathways by targeting peripheral nerves or cortical areas non-invasively.
| NIN Technique | Target Structure | Mechanism of Action |
|---|---|---|
| Transcranial Magnetic Stimulation (TMS) | Motor cortex, occipital cortex | Modulates cortical excitability, reduces cortical spreading depression |
| Transcutaneous Vagus Nerve Stimulation (tVNS) | Auricular or cervical branches of vagus nerve | Alters parasympathetic tone, reduces trigeminal nociception |
| Transcutaneous Supraorbital Nerve Stimulation (tSNS) | Supraorbital branches of trigeminal nerve | Inhibits trigeminal nociceptive pathways |
These mechanisms reduce hyperexcitability and central sensitization implicated in migraine and cluster headache pathophysiology (Bradley's Neurology in Clinical Practice, 8e, Ch. 94).