A Quick Test of Cognitive Speed: Age-Related Cognitive Slowing and Screening Thresholds in Turkish-Speaking Adults.

INTRODUCTION: A Quick Test of Cognitive Speed (AQT) is a processing-speed test that provides objective measures of aspects of executive functioning (attention, working memory, and set shifting) and has been shown to have broad cultural and linguistic applications. OBJECTIVE: To extend the availability of preliminary sample-based reference measures of AQT perceptual and cognitive processing speed for use in cognitive screening of Turkish adults. The proposed preliminary sample-based reference values should be interpreted as preliminary, sample-based reference ranges rather than clinically validated statistical reference ranges. MATERIALS AND METHODS: We administered the AQT color, form, and color-form processing-speed tests to 119 educated, healthy, Turkish-speaking adults aged 18-80 years. Participants were divided into a younger group (18-55 years; n = 53) and an older group (56-80 years; n = 66). Data were analyzed using Pearson correlation, linear regression, and one-way ANOVA following log-transformation of naming times. RESULTS: In the total group, age correlated significantly (p < 0.01) with log-normal naming times for color (r = 0.60), form (r = 0.55), and color-form combinations (r = 0.63). Linear regression indicated an average increase in naming time of between 1.5 and 2 s per decade. There were significant differences (p < 0.01) in naming times for all AQT measures between the younger and older groups, and the effect sizes were large. CONCLUSION: The present findings provide preliminary sample-based reference values for perceptual and cognitive processing speed in typically developing Turkish adults and indicate age-related decline in normal AQT performance. Educational attainment showed a small-to-moderate negative association with naming times (r = -0.23 to -0.34, p < 0.05), suggesting relatively faster performance with higher education. These findings provide preliminary reference values, but require validation in larger, more diverse samples.