THE QUANTIFICATION OF NEUROCOGNITIVE IMPAIRMENT ACROSS THE SPECTRUM OF KIDNEY DISEASE

Abstract

Over the last decade, it has become evident that patients with chronic kidney disease (CKD) are at high risk of developing neurocognitive impairment, which may influence medication/dietary adherence and quality of life. I therefore initiated a program of research that used cutting-edge robotic technology (Kinarm) to precisely and objectively quantify neurocognitive impairments in patients with CKD. To contextualize my work, a systematic review and meta-analysis was performed. Of the one-hundred and forty-eight studies identified, the vast majority used dementia screening tools to identify impairments in patients with CKD. It also demonstrated that patients who were pre-dialysis and dialysis-dependent CKD performed significantly worse than non-CKD controls.

I then performed a prospective observational study that quantified neurocognitive impairment in a cohort of patients with CKD. Forty-nine patients were recruited and assessed with the Kinarm and a traditional neurocognitive screening tool. Although, little impairment was detected by the neurocognitive screening tool, Kinarm detected impairments in up to ~50% of the cohort (task dependent). Additionally, this is the first study to demonstrate that perceptual-motor impairments are common in patients with CKD in addition to attention and executive function impairments.

Next, I characterized neurocognitive impairment in an understudied cohort: patients who experience acute kidney injury (AKI). Twenty-one patients with AKI were compared to healthy controls, and 21 active control patients matched for cardiovascular risk factors. Patients with AKI performed worse than healthy controls on attention, visuomotor, and executive function tasks. Additionally, patients with AKI performed significantly worse on attention and visuomotor domains when compared to active controls. This was the first study to prospectively investigate neurocognitive impairments after AKI.

Finally, to investigate a potential mechanism of accelerated neurocognitive impairment in patients with end-stage renal disease, I used near-infrared spectroscopy to serially measure cerebral oxygenation during hemodialysis sessions for 1 year. Ultimately, low recruitment rates deemed the study unfeasible, but interesting relationships between cerebral oxygenation, mean arterial pressure, and fluid removal rates were observed. In summary, neurocognitive impairments are common in patients with kidney disease, particularly in perceptual-motor, attention, and executive function domains. Future studies will need to address how these impairments affect quality of life.