Look for relevant journals by entering in their title, a general subject such as occupational or physical therapy, or the topic you are investigating, e.g. stroke.
Put simply, grey literature is scholarly material that hasn't been peer reviewed and/or published, like government documents, white papers, student dissertations, or conference proceedings and minutes.
Even if an article or book chapter is eventually produced from grey literature, this by definition is a secondary source and the original works from which it is derived can contain information that is never included in the journal article.
Grey literature can offer a broader view on topics, such as websites for organizations or community blog postings.
Results of studies may appear in grey literature 12 to 18 months before being published via traditional channels.
Rather than waiting years for the publication of a revised edition, authors, editors, and content creators can update information when needed, a factor that reinforces the timeliness of grey literature.
There is a great abundance of grey literature that is freely available online.
Finding these studies can be difficult, but there are a few online resources that can be used to discover this type of unpublished research.