The effects of chronic hemodialysis on verbal learning and memory

Date

1989-05

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

This study sought to determine whether significant changes occur in dialysands' ability to (a) immediately recall verbal information, (b) acquire verbal material to a criterion of one errorless trial, and (c) remember previously learned information after a 15-minute retention interval across the interdialytic cycle. Previous research indicates that memory functioning is mildly, to moderately impaired and fluctuates from one dialysis treatment to the next. However, no study reviewed to date was found to assess memory adequately. Investigators consistently failed to control for original learning. Instead, determinations about memory dysfunction have been made after presentation of information only once. An exploratory examination of organizational strategies also was undertaken in the present study. Since negative affective states are known to impact adversely on learning and memory performance, mood was also examined.

Eighteen dialysis patients with various types of renal disease were administered alternate forms of a free recall learning test (FRLT) and the Profile of Mood Scale on two consecutive days: immediately prior to their midweek dialysis treatment (predialysis) and approximately 24 hours after their dialysis treatment (postdialysis). To minimize the effects of practice, treatment order was completely counterbalanced. Order of test administration, however, was incompletely counterbalanced. Serum chemistries (blood urea nitrogen and creatinine) were obtained after each testing session.

Pre- to postdialysis performance differences in immediate memory, acquisition, retention, and subjective organization were not observed. Immediate memory span was within normal limits. All subjects learned the FRLTs to criterion and recalled an average of 87 percent of the previously learned material. Subjective organization had little effect on acquisition and recall of the FRLTs. Serum chemistries did not correlate with any of the performance measures. Despite significant daily changes in serum levels of toxic renal metabolites, there was no evidence to suggest that learning and memory functioning fluctuate across the interdialytic cycle. Significant intercorrelations between immediate memory and acquisition were observed. This finding cautions against making determinations about memory dysfunction in dialysis patients, especially if the material is presented only once and it exceeds their immediate memory span. Mood was not seen to play any role in dialysands' learning and memory performance.

Description

Citation