title: Cognitive performance before and during hemodialysis: a randomized cross-over trial.
abstract: OBJECTIVE
  Hemodialysis (HD) patients are educated and counseled during the HD procedure. There are few studies assessing whether cognitive performance varies with dialysis.
  
  
  METHODS
  Using a randomized cross-over design, 40 patients were assigned to one of two sequences: testing 1 h before dialysis followed 1 month later by testing during the first hour of dialysis (n = 21) versus testing during the first hour of dialysis followed 1 month later by 1 h before dialysis (n = 19). Cognitive tests were administered at each testing period. Mixed regression models evaluated for a dialysis effect (difference between test performance before vs. during dialysis) while adjusting for potential learning (difference between first and second tests).
  
  
  RESULTS
  In models accounting for period of testing, there was no difference in test performance between 1 h before versus during the first hour of HD for all administered cognitive tests (p > 0.05). A learning effect was detected between first and second test administration in two tests, specifically, the Word List Learning and the Digit Symbol Substitution Test.
  
  
  CONCLUSIONS
  We found no difference in cognitive performance depending on the time of testing, suggesting that cognitive tests performed during the first hour of dialysis are a valid assessment of cognitive performance.
authors: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Mass., USA.
authors: David A
authors: DA
authors: Drew
authors: Hocine
authors: H
authors: Tighiouart
authors: Tammy M
authors: TM
authors: Scott
authors: Kristina V
authors: KV
authors: Lou
authors: Kamran
authors: K
authors: Shaffi
authors: Daniel E
authors: DE
authors: Weiner
authors: Mark J
authors: MJ
authors: Sarnak
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000523:psychology; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000523:psychology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D006435:Renal Dialysis / Q000009:adverse effects