The Effort Index (EI) of the RBANS was developed to assist clinicians in discriminating patients who demonstrate good effort from those with poor effort. However, there are concerns that older adults might be unfairly penalized by this index, which uses uncorrected raw scores. Using five independent samples of geriatric patients with a broad range of cognitive functioning (e.g., cognitively intact, nursing home residents, probable Alzheimer's disease), base rates of failure on the EI were calculated. In cognitively intact and mildly impaired samples, few older individuals were classified as demonstrating poor effort (e.g., 3% in cognitively intact). However, in the more severely impaired geriatric patients, over one third had EI scores that fell above suggested cut-off scores (e.g., 37% in nursing home residents, 33% in probable Alzheimer's disease). In the cognitively intact sample, older and less educated patients were more likely to have scores suggestive of poor effort. Education effects were observed in 3 of the 4 clinical samples. Overall cognitive functioning was significantly correlated with EI scores, with poorer cognition being associated with greater suspicion of low effort. The current results suggest that age, education, and level of cognitive functioning should be taken into consideration when interpreting EI results and that significant caution is warranted when examining EI scores in elders suspected of having dementia. (Randolph, 1998) were quite rare in an outpatient clinical sample. Based on this observation, they created an embedded Effort Index (EI) for the RBANS using inversely weighted scores from these two subtests (Digit Span and List Recognition), with higher EI scores reflecting poorer effort. Using various cutoffs (>0, >3), the EI yielded good discrimination between actual cases of traumatic brain injury and three "malingering" groups (86 -96% classification accuracy). From these findings, the authors concluded that the RBANS EI is a sensitive marker for suspect effort though further validation was warranted. The sample used to develop the EI was predominantly comprised of individuals with traumatic brain injury, psychiatric illnesses, and other neurological diseases (e.g., cerebrovascular accident, epilepsy, multiple sclerosis). Although some individuals with dementia were included in this sample, cases with advanced disease that required 24-hour supervision were excluded.
KeywordsOne concern with the EI is that it utilizes raw scores from these two subtests, which might inflate the level of "suspect" effort in older adults, who tend to get lower raw scores than younger adults. Indeed, elevated levels of "suspect" effort, based on RBANS EI scores, were observed in a small sample of medically ill geriatric patients (Hook, Marquine, & Hoelzle, 2009). In that study, 31% of the sample was identified as having questionable effort using the recommended EI cutoffs (Silverberg, Wertheimer, & Fichtenberg, 2007). As cognitive impairment increased, so did the concerns about poor effort...
