Evaluation of Neurocognition in Youth with CKD Using a Novel Computerized Neurocognitive Battery

Background And Objectives: Neurocognitive problems in CKD are well documented; time-efficient methods are needed to assess neurocognition in this population. We performed the first study of the efficient 1-hour Penn Computerized Neurocognitive Battery (CNB) in children and young adults with CKD.

Design, Setting, Participants, & Measurements: We administered the Penn CNB cross-sectionally to individuals aged 8-25 years with stage 2-5 CKD (n=92, enrolled from three academic nephrology practices from 2011 to 2014) and matched healthy controls (n=69). We analyzed results from 12 tests in four domains: executive control, episodic memory, complex cognition, and social cognition. All tests measure accuracy and speed; we converted raw scores to age-specific z-scores on the basis of Philadelphia Neurodevelopmental Cohort (n=1790) norms. We analyzed each test in a linear regression with accuracy and speed z-scores as dependent variables and with (1) CKD versus control or (2) eGFR as explanatory variables, adjusted for race, sex, and maternal education.

Results: Patients with CKD (mean±SD eGFR, 48±25 ml/min per 1.73 m(2); mean age, 16.3±3.9 years) and controls (mean eGFR, 98±20 ml/min per 1.73 m(2); mean age, 16.0±4.0 years) were similar demographically. CKD participants had lower accuracy than controls in tests of complex cognition, with moderate to large effect sizes: -0.53 (95% confidence interval [95% CI], -0.87 to -0.19) for verbal reasoning, -0.52 (95% CI, -0.83 to -0.22) for nonverbal reasoning, and -0.64 (95% CI, -0.99 to -0.29) for spatial processing. For attention, patients with CKD had lower accuracy (effect size, -0.35 [95% CI, -0.67 to -0.03]) but faster response times (effect size, 0.44 [95% CI, 0.04 to 0.83]) than controls, perhaps reflecting greater impulsivity. Lower eGFR was associated with lower accuracy for complex cognition, facial and visual memory, and emotion identification tests.

Conclusions: CKD is associated with lower accuracy in tests of complex cognition, attention, memory, and emotion identification, which related to eGFR. These findings are consistent with traditional neurocognitive testing in previous studies.