This will be a statement from one of your medical sources about the work related activity you can do. The medical source should be the primary treater who is following your condition. This medical professional will document their opinion which must be supported by medical evidence including but not limited to a current mental and/or physical examination. The examination is current if in the last 60 days for mental examination and last six months for physical examination. Of course if there are changes in your condition that you want included in the Statement, the examination will have to be current as to those. It is best if the professional uses a form acceptable to the SSA called a Medical Source Statement Form, which can be a Mental MSS form and a Physical MSS form. The DDS will pay for this examination and your travel to it, if they are the ones requesting the examination.