Specificity of the 21-Item Test in two elderly samples

Area of Science:

• Neuropsychology
• Gerontology
• Psychometrics

Background:

• Assessing cognitive function in the elderly requires reliable methods to differentiate genuine impairment from suboptimal effort.
• Malingering detection is crucial in clinical and forensic settings, particularly in aging populations where cognitive decline is prevalent.

Purpose of the Study:

• To evaluate the specificity of the 21-Item Test in identifying malingering within an elderly cohort.
• To determine if age and cognitive status influence the test's accuracy in detecting non-credible responding.

Main Methods:

• The 21-Item Test was administered to two groups of elderly individuals: 20 community-dwelling and 53 nursing home residents.
• Cognitive status was assessed using the Short Portable Mental Status Questionnaire (SPMSQ).
• Specificity was calculated based on established cutoffs for the 21-Item Test's forced-choice component.

Main Results:

• The 21-Item Test exhibited 100% specificity, with no participants from either group scoring in a range indicative of malingering.
• Age and cognitive impairment (as measured by SPMSQ) did not significantly affect the test's ability to accurately identify effort.
• The established interpretation cutoffs for the 21-Item Test were found to be relatively insensitive to age and cognitive deficits.

Conclusions:

• The 21-Item Test is a highly specific instrument for detecting malingering in elderly individuals, irrespective of their cognitive status.
• The findings support the use of the 21-Item Test as a reliable measure of response validity in geriatric neuropsychological assessments.