The effect of Sudoku puzzle solving on memory and anxiety of hemodialysis patients: a randomized controlled clinical trial.

Introduction: Cognitive and psychological disorders are among the most important outcomes of the end stage of renal disease. Treatments have neither definitely prevented the disorders' progression nor cured them. This study aims at evaluating the effect of solving a Sudoku puzzle on memory and anxiety in hemodialysis (HD) patients.

Materials and methods: This randomized controlled clinical trial study was conducted on 64 HD patients. The samples were randomly assigned either to the control group (n = 32) or Sudoku (intervention) group (n = 32). The study lasted for four weeks. The anxiety and memory of the participants were measured by the Spielberger State Trait Anxiety Inventory (STAI-S) and Wechsler Memory Scale (WMS) at the beginning and end of the study. The intervention group solved the Sudoku puzzle within 20 min for four weeks, three times per week (12 times), 15 min after the HD onset, the control group received no intervention. To evaluate the effect of the Sudoku puzzle on momentary anxiety, the state anxiety of all samples was measured and recorded in the first session of the study, 40 min after the onset of the first HD session. The data were analyzed with SPSS software version 25.

Results: The mean and standard deviation of the anxiety score were 82.71 ± 5.1 and 70.93 ± 18.0 in the Sudoku group (p = 0.001) and 82.43 ± 5.77 and 82.06 ± 4.55 in the control group at the beginning and the end of the study, respectively (p = 0.778). Moreover, the mean and standard deviation of the state anxiety score in the first session were 41.37 ± 3.29 and 38.5 ± 2.9 in the intervention group (p = 0.001) and 39.5 ± 2.9 and 42.15 ± 2.73 in the control group (p = 0.001) before the HD onset and 40 min after the HD onset, respectively. There was no statistically significant difference in memory scores in the Sudoku group before and after the intervention. However, the covariance test showed that at the end of the study, there was a statistically significant difference between memory scores in the control and intervention groups(p = 0.048). The results showed that there is a statistically significant difference in the post tests between the two groups in terms of anxiety, state anxiety and memory (p ≤ 0.05).

Conclusion: Sudoku solving seems to play an effective role in reducing anxiety and state anxiety in HD patients, but it has little effect in improving memory. Therefore, it is recommended to use it as an adjunctive treatment to control anxiety and improve memory in hemodialysis patients.