B - 49 Exploring the Factor Structure of Sluggish Cognitive Tempo and Impact on Processing Speed Performance.

Abstract

The present study investigated: 1) factor structure of the Sluggish Cognitive Tempo (SCT) sub-scale from the Barkley Adult ADHD Rating Scale-4th Edition (BAARS-IV) and 2) the association between SCT sub-factors and processing speed. Cross-sectional data were collected from 586 adults undergoing neuropsychological evaluation for suspected attention-deficit/hyperactivity disorder (ADHD) at an academic medical center. Patients were excluded if they failed two or more performance validity tests and/or had not completed all measures. Final sample included 155 patients (Mage = 28.52; Meducation = 16.26; 63.2% female; 38.1% White, 21.9% Hispanic, 20% Black, 12.9% Asian, 7.1% other race/ethnicity; 69% diagnosed with ADHD). Factor structure of the SCT sub-scale was investigated via exploratory factor analysis with Oblimin rotation. Hierarchical multiple regressions were used to assess the relationship between SCT sub-factors and processing speed (Wechsler Adult Intelligence Scale-4th Edition, Processing Speed Index), controlling for estimated intelligence (Test of Premorbid Functioning) and self-reported inattention (Clinical Assessment of Attention Deficit-Adult). Kaiser-Meyer-Olkin measure [KMO = 0.78] and Bartlett's test [χ2(36) = 469,p < 0.001] suggested the data were factorable. Parallel analysis scree plot suggested a two-factor solution: "Cognitive Complaints" and "Lethargy" accounting for 46.3% of SCT scale variance. Only Lethargy predicted processing speed in the first (beta = -0.221, p < 0.05) and final models (beta = -0.197, p < 0.05). The overall model including estimated intelligence and inattention accounted for 6.2% of the variance in processing speed (F(4,150) = 3.57, p < 0.05). Previous studies demonstrated mixed results of two or three sub-factors of SCT including daydreaming, lethargy, and/or cognitive complaints. Present findings support the more parsimonious two-factor solution in a clinical sample. Higher lethargy complaints are modestly associated with poorer processing speed.