People with dementia are of major importance in studying effort tests.  The reason is that they are more cognitively impaired than almost all other groups.  Therefore, they face the highest risk of being classified as poor effort when they are actually trying their best.  Children with a FSIQ below 70 are also important to study for the same reasons.  If we can achieve extremely few false positives for poor effort in these samples, which we can, then it follows that those groups with less impairment will also have very few false positives (e.g. adults with mild brain injury).

Q) Which effort tests can achieve 95% or 100% specificity in dementia and also in developmentally disabled children?

A) Most effort tests cannot do so.  The outcome of such tests (e.g. TOMM, CARB, ASTM) is only a pass or a fail and many people with dementia cannot pass.  Lowering the cut-off does not solve the problem.  However, the WMT, MSVT & NV-MSVT produce specific profiles in dementia, which are not the same as those arising from poor effort in people feigning dementia.  As a result, all three tests can each achieve 95% or 100% specificity in dementia and also in developmentally disabled children, including those with mental retardation.  Using the WMT, MSVT and NV-MSVT in combination does not lower specificity in those with genuine very severe impairment (e.g. dementia) but it enhances sensitivity to poor effort.  If we know that a test has extremely high specificity in very impaired people, then when someone fails it, they are either very severely impaired, which will usually be obvious, well documented and clinically evident, or their effort is poor.  The emphasis within this approach is in avoiding false positives at all costs.

For more details please see these papers: