What are the barriers for new assistive technology?

Advances in technology have increased the number of assistive-technology devices available to individuals with disabilities. However, problems -- from regulatory hurdles to niche markets -- still make it difficult and cost-prohibitive for some startups to get their inventions to consumers. The Toronto Star (5/31)  http://www.thestar.com/news/world/2015/05/26/great-advances-being-made-in-assistive-technology.html