Differential impairment of psychomotor efficiency and processing speed in patients with chronic kidney disease.
BACKGROUND
Cognitive impairment has been documented in patients with chronic kidney disease. In a recent paper, improvements in cognitive function were seen in hemodialysis (HD) patients switched from conventional HD to nocturnal HD, in two of three domains of cognitive function. Based on these findings, we hypothesized that functional decline may occur differentially in some domains more than others.


METHODS
Using a cross-sectional study design, patients optimized on medical treatment at a predialysis clinic were tested using a battery of neuropsychological (NP) tests measuring three domains of cognitive functioning-attention & working memory skills; psychomotor efficiency & processing speed; and learning efficiency. Clinical subjective symptoms for cognitive functioning and depression were measured using the Patient's Assessment of Own Functioning (PAOF) inventory and the Beck Depression Inventory (BDI).


RESULTS
One hundred and three patients aged 64.6+/-12.4 years were recruited. Of these, 40% were diabetic, with a mean Charlson comorbidity score of 4.4+/-2.1. Depression (defined as >16 on the BDI score) was seen in 11 patients. After adjustment for comorbid diseases, hemoglobin, the use of neurodepressor medication, and parathyroid hormone (PTH) values, renal function was negatively correlated with psychomotor efficiency & processing speed, but not with attention & working memory or learning efficiency scores.


CONCLUSIONS
Chronic kidney disease is associated with a decline in psychomotor efficiency & processing speed, but not with attention & working memory or learning efficiency.
Jassal
Sarbjit V
SV
Department of Medicine, University Health Network, 8N-857, 200 Elizabeth St., Toronto, ON, Canada M5G 2C4. Vanita.Jassal@uhn.on.ca
Roscoe
Janet
J
LeBlanc
Denise
D
Devins
Gerald M
GM
Rourke
Sean
S
D000203:Activities of Daily Living; D000368:Aged; D003072:Cognition Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*