WORDS: A New Verbal Memory Test to Evaluate Cognitive Health in a Zambian School-aged Population.

Abstract

Objective: The paucity of psychometric instruments is one of the challenges preventing the effective implementation of child cognitive health testing in Sub-Saharan countries. WORDS is a new memory assessment tool originally validated in a Zambian school-aged population.

Design: WORDS involves the standardized administration of a multitrial, verbal, free recall task with acquisition and immediate recall of a structured list of 16 words, followed by a second acquisition and delayed recall after a five-minute interference. A field trial was carried out to evaluate test feasibility of use, reliability, and validity. A total of 448 children, aged 5 to 17 years, were recruited at multiple Zambian clinical sites and schools.

Results: WORDS provides a summary score of recall productivity derived from the sum of items correctly retrieved at immediate and delayed recalls. Recall productivity showed a moderate/good reliability at test-retest with alternate forms (N=53, 95% confidence interval of the intraclass correlation [CI-IC]: 0.73, 0.54-0.85). Recall productivity was found to increase with age. Altered memory functioning, as indicated by lower recall productivity, was associated with poor health status resulting from chronic neurologic or medical disease or prolonged exposure to psychosocial stress and deprivation [recall productivity, range: 0-32, healthy mean (standard deviation [SD]): 15.36 (4.7) vs. poor health, mean (SD): 12.62 (4.8); F (1,446)=27.79, p=0.000, d=0.58].

Conclusion: WORDS addresses the need for new psychometric tools to evaluate memory in a school-aged Zambian population. WORDS has the potential for clinical utility to evaluate cognitive development, as well as the effect of different health conditions on memory. Study results warrant research to further validate its use in Sub-Saharan clinical and epidemiological research settings.