Trajectory and variability characterization of the Montreal cognitive assessment in older adults.

BACKGROUND: The Montreal cognitive assessment (MoCA) has become one of the most widely used cognitive screening instruments since its initial publication. To date, only a handful of studies have explored longitudinal characteristics of the MoCA.

AIM: The aim of this study is to characterize the trajectory of MoCA performance across a broad age continuum of older adults.

METHODS: Data from 467 cognitively normal participants were used in this analysis. The sample was grouped into four strata based on the participants' age at baseline (60-69, 70-79, 80-89, and 90-99). Mixed model repeated measures (MMRM) analysis and mixed-effects spline models were used to characterize the trajectory of MoCA scores in each age stratum and in the entire sample. Intrasubject standard deviation (ISD) was used to characterize the natural variability of individual MoCA performance over time.

RESULTS: The ISD values for each of the age strata indicated that year-to-year individual variation on the MoCA ranged from zero to three points. MMRM analysis showed that the 60-69 stratum remained relatively stable over time while the 70-79 and 80-89 strata both showed notable decline relative to baseline performance. The mixed-effects spline model showed that MoCA performance declines linearly across the older adult age span.

DISCUSSION: Among cognitively normal older adults MoCA performance remains relatively stable over time, however across the older adult age-span MoCA performance declines in a linear fashion. These results will help clinicians better understand the normal course of MoCA change in older adults while researchers may use these results to inform sample size estimates for intervention studies.

CONCLUSION: This study provides an enhanced view of the MoCA's intraindividual trajectory in normal elderly aged 60 and older.