Keeping focused to remember what you read is a frequent problem. The basics are:
1) Can the child accurately read the words;
2) Does the child know the process of comprehending; and
3) Does the child know his or her fastest way of remembering?
We all have our own unique ways of comprehending and remembering. Whether the child has ADHD or ADD or any other challenge, or even is a regular ed student, he or she has his or her own best way of comprehending and remembering.
The first step is to find your child's unique, best, and fastest way of learning. The second step is teaching how to read text, whether a novel or content area book, in this style which will then put the material into long-term memory.
For example, if your child is a kinesthetic learner, then he or she comprehends and recalls material best using a kinesthetic approach. You can see this article on kinesthetic learners. http://latitudes.org/tips-for-teaching-kinesthetic-learners/ If this type of learner is only presented with visual and auditory lessons, the learning process will not be as strong. It will take longer, be a struggle, and contribute to more distraction.
Students are often labelled ADD or ADHD when in reality they are not being taught through their best way of learning and remembering.