The term DNM Stands for Dermo (skin), Neuro (nervous system) Modulation (a change from one state to another). It is a method of manual therapy/massage therapy used to change the state of the nervous system from a painful, hyperactive state to a less painful and reactive one through the skin receptors. Diane Jacobs, a Canadian PT with 40 years of experience, developed DNM as a way to treat people with chronic and persistent pain better. I have had the pleasure of learning from and working directly with Diane over the last four years.
She explains the background of the method:

     

    The nervous system is comprised of 72 km of nerves and a brain 5 times bigger than it needs to be to run a critter our size. Even with all this length, even with the giant brain, it's tiny, only 2% of the whole body. Still, because it's busy 24/7, even when we're asleep, and because it runs all operations, it sucks up an amazing 20% (!) of all available oxygen and glucose all the time at speeds of about 270 miles per hour, so it's a big energy suck. You are part of it. It's not part of 'you' how we usually think of our body parts. You are part of it. 'You' are the human bit in there, but most of it we have in common with all the other critters out there that have vertebrate nervous systems. It runs 'you'. It looks after 'you'. It keeps 'you' alive. It puts 'you' to sleep at night so it can do other things, but it keeps your heart beating and your lungs working, right? It's your survival machine and your threat detector. It wakes 'you' up in the morning because it needs you to get it something to eat. It never shuts off! It's your operating system. It's an old, evolved thing, and some parts are really old while other parts are quite new, and they're all hooked together, and sometimes it can get itself into a glitch. Usually, that's all that's the matter. So, we do a systems check and help it fix itself. 
This unique nervous system goes all the way from the brain to the skin and back. There are Billions of sensors in our skin. On average sensors are one to two cells apart. These sensors tell our brain what is happening in the world around us, what is happening within us and what is happening to us. There are many different sensors and each have specific rolls. There are sensors for just heat others for just cold, there are sensors for just heavy pressure others for light pressure, ones for quick stretch others for slow stretch and so on...

DNM is a method of manual care that puts the patient and their needs first. Instead of operating a recipe treatment, the treatment is an interaction between the patient and the therapist. We work together to find the areas that need attention and remove the tenderness and pain felt in that area. The focus is on changing the signalling within the nervous system to decrease your pain. Pain does not happen in the muscles and other tissues but in the nervous system itself; therefore, whether or not the area of pain is damaged, we can reduce that pain with DNM.
 
The manual part of DNM involves changing the input signalling from some of these receptors to help the brain get a better picture of what is happening to/in the body. We want to show the Brain that the area where you feel pain is not under the threat that the brain perceives it to be in. 

Some effects of an effective DNM treatment:

You will get sleepy
You will have less swelling/inflammation after
You will feel warming, an ease of movement, and a softening of hardened muscles
Your pain relief will continue throughout the day of the treatment and will usually peak 72 hours after the treatment.

See it in action