Neuropsychological change in Mild Cognitive Impairment using estimated standardized regression‐based formulas

Abstract

AbstractBackgroundNeuropsychological change in Mild Cognitive Impairment (MCI) can be tracked with repeated assessments to determine if an individual remains stable or progresses to dementia. However, few studies have quantified these cognitive changes over time, especially using standardized regression‐based (SRB) change formulae.MethodParticipants included 283 MCI patients from a cognitive disorders clinic who were assessed twice with a comprehensive neuropsychological battery across approximately one‐ and one‐half years. SRB z‐scores were calculated for each of 17 test scores this battery for each participant. Change on these 17 z‐scores were examined for the entire sample, as well as between two subgroups: those who remained MCI on follow‐up (i.e., MCI‐Stable) and those who progressed to dementia (i.e., MCI‐Decline).ResultFor the entire MCI sample, significant declines were observed on all 17 z‐scores (p<0.001), with the largest declines occurring on memory tests. When the two subgroups were compared, significant differences were observed between these two groups across nearly all cognitive domains, with the largest differences being on tests of attention and processing speed. For these group differences, those in the MCI‐Decline group showed the most decline compared to the MCI‐Stable participants. However, notable cognitive decline was also observed in the MCI‐Stable group.ConclusionThis study highlights the degree of cognitive decline that occurs in MCI across time, even among those who remain “stable” on follow‐up. It also highlights the value of the SRB method in more accurately capturing and quantifying cognitive decline, which may help identify individuals most vulnerable to MCI progression.