Patrick was 8 years old. Steroids were not recommended. There was no imaging and no way to predict his loss of ambulation. Sure, he fell occasionally. Some days more than others. There was one day in the summer of 1988. We had been active most of the day. We went swimming, to the mall, and ended the day with a cookout. Patrick walked and walked. He asked me to help him to the bathroom. He fell. It was one of those FALLS, as if his legs were pulled out from under him. I had no excuses in my head… his shoes untied… he tripped on the rug… he bumped into the sink. Rather, he just sat down on the floor. I helped him stand and found he was unable. He simply said, “My legs won’t work anymore.” He had lost ambulation. He had no more steps to take.
I wrestled with this, trying to understand, trying to figure it out, to have some sort of explanation that made sense. I thought about how many muscle fibers might be required to walk. And I made it up. For example, if it takes 10,000 muscle fibers to walk, boys stop walking when that last fiber degenerates, when only 9,999 are left, walking is impossible. This may sound a little crazy, but the truth is, that strength and function are not the same. Function remains while strength decreases. And when strength diminishes to a critical point, function is lost.
The overall objective of the Imaging DMD natural history study is to validate the potential of noninvasive magnetic imaging (MRI) and spectroscopy (MRS) to monitor disease progression and to serve as an outcome measure in clinical trials – thus far, 152 subjects (126 with Duchenne and 26 healthy subjects) across three sites.
The T2 images monitor inflammation and fibrosis. The T3 images monitor water content. The data from this study is amazing. It is extraordinary to see that some muscles, the soleus and vastus lateralis (weight bearing) undergo significant degeneration, while some accessory muscles such as the gracilis remains well preserved.
Here’s what we are learning: