Effects of Intradialytic Cognitive and Physical Exercise Training on Functional Status of Hemodialysis Patients (DIAKOG)

Effects of Intradialytic Cognitive and Physical Exercise Training on Functional Status of Hemodialysis Patients

Effects of Intradialytic Cognitive and Physical Exercise Training on Functional Status of Hemodialysis Patients: Randomized Interventional Trial

The aim of this study is to investigate the effect of cognitive training combined with physical exercise on cognitive function, physical performance and frailty indicators in the hemodialysis population.

The prevalence of cognitive impairment in hemodialysis (HD) patients is extremely high. Despite the well-documented benefits of interventions on cognitive function, there is a widespread call for effective strategies that will show the long-term consequences in patients undergoing dialysis. A randomized controlled intervention trial to examine the effects of a combined non-pharmacological intervention in the form of intradialytic physical exercise and intradialytic cognitive training on cognitive function, indicators of frailty, and physical performance measures in HD patients will be conducted. The group of patients receiving the study intervention will be compared to the control group receiving standard HD care. The duration of the intervention will be 12 weeks (3 days a week). We will use sensitive instruments (cognitive domain tests) to assess cognitive functions. The primary outcome of the study at 12 weeks will be performance on the Alertness subtest of the computerized Test of Attentional Performance. Secondary study outcomes will be: Performance in other domains of cognitive function (executive function, psychomotor speed, information processing efficiency, working memory, attention), physical fitness (10 repetition sit-to-stand test, timed up and go test, handgrip strength test, spontaneous gait speed, Stork balance test), and assessment of frailty (Edmonton Frail Scale). Study outcomes will be assessed at baseline, immediately after the 12-week intervention, and six months after the end of the study without specific further intervention (retention effect assessment). This study will be among the first to test the synergistic effects of a uniquely designed physical exercise and cognitive training intervention on functional status in HD patients. It is believed that results will contribute to dementia prevention research by demonstrating the long-term efficacy of the presented combined intervention.

cognitive functions, hemodialysis, physical activity, intradialytic training, non-pharmacological interventions

This group will perform combined intradialytic cognitive and physical exercise training. First, they will exercise during dialysis (3 times a week; 12 weeks) for ~30 minutes on a customized ergometer. They will start with a 3-min warm-up, then the resistance will be implied to each individual according to the rate of perceived exertion of 4th to 5th grade on a 10-grade Borg scale. After a break, they will be given tablet computers in order to play "brain games" on a CogniFit platform (~30 - 45 min).

12 weeks (3 times a week): patients will cycle on an adapted ergometer during their dialysis procedure. The exercise program will be run by kinesiologists. Participants will start with 15 minutes of cycling and then gradually increase the time and intensity. After the physical exercise session, they will continue with cognitive training. This training will be done on a tablet computer on a CogniFit platform (~30 minutes). The "brain games" on mentioned platform automatically adapt to individual cognitive abilities.

The Test of Attentional Performance (TAP) is a software package that can be used primarily to examine attention functions. The rationale for the selection of the main outcome: low learning effect, most probably affected by physical exercise, attention is one of the most affected cognitive domains in dialysis patients. From the TAP test battery, subtests Alertness, Selective attention, Divided attention, and Sustained attention will be included.

Montreal Cognitive Assessment (MoCA) is a global cognitive function assessment tool covering eight cognitive domains and is used to screen patients for cognitive impairment.

Symbol Digit Modalities Test (SDMT) will be used to assess the psychomotor speed, efficiency of information processing, ability to switch between mental sets of the information and to maintain and manipulate information in working memory. It is a reliable and valid test for assessing information processing speed and efficiency and executive functioning domains.

Performance of the sit-to-stand test involves activation of the lower limb muscles; the test measures lower limb strength. Participants are required to 10 times stand up from and sit down on an armless chair as quickly as possible. Their arms should be folded across their chest.

Frailty indicator will be assessed by the Edmonton Frail Scale (EFS). The EFS score ranges from zero to 17 points. Severe Frailty is defined as a score of 12-17 possible points; apparent vulnerability is a score of 6-11 points; and non-frail is a score of 5 or less points.

The Timed Up and Go (TUG) test is a simple evaluative test used to measure functional mobility. It will be used to estimate risk of falling and ability to maintain balance while walking.

Inclusion Criteria: dialysis patients on renal replacement therapy with chronic hemodialysis duration of hemodialysis treatment for at least 3 months capable of independent walking and independent feeding Exclusion Criteria: the presence of chronic malignant or infectious disease uncontrolled arterial hypertension with an average of the last five pre-dialysis blood pressure values above 180/100 mm Hg, unstable angina pectoris or Canadian Cardiovascular Society class 2-4, heart failure New York Heart Association class 3 and 4, the presence of a psychotic illness or a mental disability, a condition with an amputated limb (more than 2 fingers on the lower limb and / or more than 2 fingers on the upper limb) any other condition that causes the clinical unstability of the patient (i.e. repetitive gastrointestinal hemorrhagies, liver cirrhosis with frequent exacerbations)

Bogataj S, Trajkovic N, Pajek M, Pajek J. Effects of Intradialytic Cognitive and Physical Exercise Training on Cognitive and Physical Abilities in Hemodialysis Patients: Study Protocol for a Randomized Controlled Trial. Front Psychol. 2022 Jan 25;13:835486. doi: 10.3389/fpsyg.2022.835486. eCollection 2022.