Around this time DMD boys will lose the ability to walk independently and will start using a wheelchair on a more regular basis.

Increased weakness may start spreading to the arms and neck. Most teenagers living with Duchenne are able to use their arms and fingers throughout this phase, so they will still be able to write and use a computer.

Lungs will weaken which may lead to difficulties with breathing. Breaths may become shallower, and the ability to cough lessens. This may lead to more chest infections because it's harder to clear mucus and germs from the chest. As breathing weakens oxygen levels in the blood may fall, leading to tiredness, irritability, headaches on waking, inability to sleep and vivid dreams. Breathing respirators, and cough assist technologies can help with this. In time, support will be needed breathing, first overnight and then during the daytime.

The heart muscles will also be affected. This is called cardiomyopathy, and there are treatments available to help.

THINGS TO CONSIDER: speech therapy, physiotherapy to remove mucus from the chest, non-invasive ventilation, techniques to increase the air flow into the lungs, breathing respirators, hoists, discussions about physical access and emotional support outside the home, respite for carers.