Helthcare & Wellness
Nov 1, 2017
HIT THE RIGHT NERVE
A new type of treatment, vagal nerve stimulation (VNS), may offer hope for people who don't improve with conventional depression treatment A small battery-powered device like a pacemaker is inserted under the skin in the neck.
By JORGE MATIAS
The neck the implant emits pulses of weak electrical current to stimulate part of the vagus nerve. The vagus normally monitors our vital functions; it collects information about our breathing, heart rate and joint position, and sends signals back to the brain that tell it to respond if there are fluctuations.
No one fully understands how VNS works in severe depression that has been unresponsive to other treatments.
VNS is being underused, especially among people who have responded to ECT (electroconvulsive therapy) but who have relapsed. And it is known that if we wait more than five years before offering the treatment, it's less likely to work.
But nothing that works is ever entirely free of side-effects; so what are the downsides? The main side-effect is hoarseness because the recurrent laryngeal nerve (that supplies the voice box) comes off the vagus nerve. But they can temporarily switch off the device by holding a magnet over it.
VNS stimulates the nerves that travel back up to the brain's limbic system (the area that controls emotion, mood and behaviour) to release more neurotransmitters (chemical messengers between nerves).
VNS can be used to treat severe, treatment-resistant depression but there is not much evidence about how well it works or how safe it is, so far. Other side-effects including coughing, shortness of breath, changes to heart rhythm and worsening depression or mania are also pointed as downside for this treatment.
However, VNS is already approved in many countries to treat children with epilepsy who haven't responded to standard treatments and, there is a lot of excitement about recently published work showing a positive effect in the treatment of rheumatoid arthritis and Crohn's disease.
Contacts * www.ncl.ac.uk * Institute of Neuroscience * Newcastle University, NE1 7RU, United Kingdom *
Tel: (0191) 208