I can definitely relate to these problems as an educator with more than one decade's worth of experience teaching and tutoring students of all different ages who have short attention spans, ADHD, and other special needs.
I am a huge proponent of project-based learning. By designing lessons and curricula around student innovation rather than test-taking skills, students are able to contribute to their own everyday learning in many meaningful ways regularly that allow them to express and apply their expanding inner knowledge base in ways that feel both comfortable and challenging for them. Many special-needs students are highly creative people and their minds are typically moving a mile a minute even if the people around them can't/don't necessarily sense that reality externally.
Along those lines: differentiated instruction really comes into play here. Teaching different students different ways is key to helping them grow and reach their full potential at all times. Since the one-size-fits-all methodology of academic instruction is fading fast with every new generation of learners, the more creative a teacher can be with their everyday teaching, the more enjoyable and beneficial learning and corresponding output will appear for everyone involved on both the giving and receiving ends of things. Using a wide variety of learning and teaching resources that appeal to the visual, auditory, artistic, holistic, left- and right-brain wavelengths respectively can make for a much more well-rounded learning experience for one's pupils and helps to enhance academic diversity all the while in the long run. Music, educational media, and technology are essential tools in this regard. When mixing and mingling multiple meaningful means of teaching and learning together into a pot of highly enlightened wisdom, one gets results that allow effective application of learning like never before, leading to contentment on both the students' and teachers' parts, separately/individually and together.
Good luck with your teaching, and keep up the great work that you are already doing and have done too! Cheers! :)