Some Unique Considerations
There are several special issues related to cognitive and functional assessment that are important for the design of behavioral intervention trials and assessment of outcomes in these studies.
Cognition or Capacity as the Outcome
The high correlation between assessments of cognitive performance and functional capacity has led to the question (Leifker, Patterson, Bowie, & Harvey, 2010), partially supported by data: Are these actually different assessments of the same general ability domain (Harvey, Raykov, et al., 2013)? Future research will need to determine the differential suitability of these indices for outcomes assessment in treatment studies. Given that abbreviated assessments of both cognition and functional capacity are available, it would seem prudent to invest the time to assess both of these domains. This issue may change with the continued development of computerized functional capacity assessments, as highly validated functional capacity assessments may lead to increased validity and practicality.