Slow and Steady Does Not Always Win the Race: Investigating the Effect of Processing Speed across Five Naming Tests.

Abstract

This retrospective study investigated the effect of processing speed on confrontation naming performance via five naming tests with varying time components. The effect of processing speed, as measured by the Wechsler Adult Intelligence Scale-Fourth Edition Processing Speed Index (PSI), and cognitive impairment were examined using Boston Naming Test, Neuropsychological Assessment Battery Naming Test, Visual Naming Test (VNT), Auditory Naming Test (ANT), and Woodcock-Johnson III Rapid Picture Naming (RPN) performance among a mixed clinical sample of 115 outpatient veterans. PSI scores accounted for 5%-26% of the total variance in naming test performances. Comparison of cognitively impaired versus unimpaired participants found significant differences and medium to large effect sizes (η2=.08-.20) for all naming measures except ANT tip-of-the-tongue responses. After controlling for the effect processing speed, VNT tip-of-the-tongue responses also became non-significant, whereas significant group differences remained present for all other naming test scores, albeit with notably smaller effects sizes (η2=.06-.10). Confrontation naming test performance is related to cognitive processing speed, although the magnitude of this effect varies by the demands of each naming test (i.e., largest for RPN; smallest for VNT). Thus, results argue that processing speed is important to consider for accurate clinical interpretation of naming tests, especially in the context of cognitive impairment.