Your article is very informative. To improve it even further, I'd suggest going deeper into detail and talking about popular and common disabilities. For example, you can talk about cataract for visual impairments http://www.allaboutvision.com/conditions/cataracts.htm. You can also talk about Parkinson's disease which has an effect on one's speech, movement, balance etc http://www.parkinson.ca/site/c.kgLNIWODKpF/b.5184077/k.CDD1/What_is_Parkinsons.htm.