Analysis of Practice Effects Across Cognitive Domains in Mild Cognitive Impairment

Serial assessments provide clinically useful information about progression of a disease. Since individuals with mild cognitive impairment are less likely to show decline in cognitive areas other than memory, it is important to analyze which domains are more susceptible to practice effects than others.
The appearance of practice effects in serial assessments is a common challenge for clinicians interpreting neuropsychological tests. Detecting true change can be altered by factors such as test intervals, standardization procedures, alternate forms, respondent characteristics, and cognitive domains impaired in a clinical population. Some cognitive domains such as learning, memory, and executive functioning are known to be more susceptible to practice effects than others such as processing speed, attention, and language. Normal adults are also shown to have greater practice effects over multiple exposures than disease populations. The review supports the claim that healthy adult individuals are more likely to improve and show greater practice effects during serial assessments than clinical populations. In patients with mild cognitive impairment (MCI), domains that rely on recall and learning test rules like learning, memory, and executive functioning tend to be more susceptible to practice effects than crystallized and skill - based domains such as language, processing speed, and attention. Future research should focus on developing reliable change indices for each cognitive domain and possibly each neuropsychological test to help provide a comparison and detect true change in test scores. Studies should also focus on developing alternate equivalent forms, which would help minimize practice effects across populations.