Event- and time-based prospective memory in hemodialysis patients

Objective The present study investigated whether hemodialysis (HD) patients exhibit future memory impairment (PM; the capability of remembering to perform expected future actions) and exploring relevant factors of PM task performance. Methods Sixty HD patients and 60 healthy controls matched by age are enrolled in the Mini-Mental State Examination (MMSE), Finger Span Test (DST), Oral Fluency Test (VFT), Ray Auditory Oral Learning Test (RAVLT), Received Stroop Color Word Interference Test (SCWT), and event-based PM (EBPM) and time-based PM (TBPM). Results There were no significant difference between the patients and controls in the DST-Forward digit span (9.00 +/- 1.25 versus 8.97 +/- 1.33, p = 0.96), the DST-Backward digit span (5.23 +/- 1.98 versus. 4.60 +/- 1.65, p = 0.11), the RAVLT of delayed recall (7.28 +/- 2.36 versus 6.87 +/- 3.33, p = 0.09) and the VFT for animals (16.70 +/- 3.50 versus 17.68 +/- 5.45, p = 0.56). By comparison, patients had a much worse performance than controls on the MMSE (29.10 +/- 0.84 versus 28.33 +/- 0.77, p < 0.001), the RAVLT of total recall (44.47 +/- 5.82 versus 40.03 +/- 10.46, p < 0.001) and delayed recognition (6.93 +/- 1.49 versus 5.4 +/- 1.33, p < 0.001), the SCWT reaction time in reading (6.47 +/- 1.05 versus 7.47 +/- 1.86, p < 0.001), color naming (9.07 +/- 1.29 versus 11.43 +/- 2.34, p < 0.001), interference (8.78 +/- 1.92 versus 10.22 +/- 2.91, p < 0.001) and inhibition/switching (14.53 +/- 2.90 versus 19.85 +/- 4.69, p < 0.001), the VFT for fruit (17.47 +/- 3.18 versus 15.92 +/- 4.56, p < 0.001), the EBPM task (7.85 +/- 0.40 versus 7.08 +/- 1.43, p = 0.01), and the TBPM task (3.30 +/- 1.31 versus 2.26 +/- 1.82, p < 0.001). Conclusions Our results suggest that EBPM and TBPM are impaired in HD patients and that PM may be applied to help evaluate cognitive dysfunction in HD patients.