Impact of Chronic Kidney Disease on Postural Stability in Children
Condition: Chronic Kidney Diseases
MeSH terms: Kidney Diseases; Renal Insufficiency, Chronic
Study type: Observational

Summary: 
      Background: Chronic kidney disease is associated with comorbid conditions that result in
      physical impairments.

      Objectives: Investigate the impact of chronic kidney disease (CKD) on postural stability in
      children compared with age matched typically developing children using Human Assessment
      Computer (HUMAC) balance system.

      Design: An observational design (cross-sectional study). Settings: The assessment procedures
      were conducted at the Nephrology Unit, Zagazig University Hospitals.

      Participants: Seventy-five children, age ranged from 8 to 15 years represented three groups
      of equal numbers; control group (typically developed), non-dialysis (stage 3 and 4) and
      hemodialysis group.

      Outcome measures: The HUMAC balance system was used to assess the limits of stability, center
      of pressure and sensory organization and balance.
    

Detailed description: 
      Methods Study design This study is an observational cross-sectional design (prospective
      database study).

      Participants and setting Participants included children with CKD extracted from a data set of
      731 individuals with CKD diagnoses, who receive regular medical follow-up/hemodialysis at
      Nephrology Unit, Zagazig University Hospitals. The study was conducted from January 2018 to
      January 2020 in accordance with the Declaration of Helsinki (Code of Ethics of the World
      Medical Association). The study protocol was approved by the Ethical committee of the Faculty
      of Physical Therapy, Cairo University, Egypt (No.P.T.REC/012/002169). Children's
      par-ticipation was authorized by a signed written consent form with parent's/legal guardian's
      acceptance for participation before starting the study procedures.

      Participants Fifty eligible volunteer children with CKD were recruited from Nephrology Unit,
      Zagazig University Hospitals to be enrolled in this study and allocated into either
      hemodialysis (on hemodialysis) or non-dialysis group (children at stage 3 and 4).

      Eligible criteria:

        -  Medically diagnosed with CKD (regardless of medical history),

        -  Age ranged from eight to fifteen years,

        -  Both genders

      Participants were excluded if they had:

        -  Communication problems such as intellectual disability, autism, Down syndrome, or
           cerebral palsy,

        -  Significant visual or hearing problems,

        -  Any neurological and/or musculoskeletal disorders which influence postural stability,

        -  Chronic cardiovascular or pulmonary disorders. Twenty-five volunteer typically developed
           age matched group were enrolled as control group.

      Basic demographic and clinical information Demographics and physical characteristics (age,
      sex, weight, height) and clinical data (renal function test, recent hematology and blood
      chemistry counts, co-morbidity, and medication) were recorded from medical reports to confirm
      diagnosis.

      Study power and sample size Sample size was predestined before conducting the study by
      G*POWER statistical software (Franz Faul, Universitat Kiel, Germany; version 3.1.9.2) [F
      tests- ANOVA: Fixed effects, one-way, α=0.05, β=0.2, and large effect size] with the number
      of groups=3, giving a total number of 66 participants to be recruited in this study.

      2.5. Outcome measures The Human Assessment Computer (HUMAC) Balance System, primarily being
      part of a video game appliance (Wii Balance Board), is a distinct technology used in
      assessment and rehabilitation of postural control. It is an affordable, portable and
      prevalent obtainable force plate provides the patient and tester with visual feedback as well
      as numerical data. The system displays several reporting options with objective datum
      providing clinicians with comprehensive case progression which is used for baseline and
      follow-up analysis with eight programs to choose from (HUMAC balance, 2017; Blosch et al.,
      2019). The HUMAC-type technology has been found to detect more imbalances than traditional
      tests (Merchant-Borna et al., 2017). In the current study limits of stability, COP and the
      Clinical Test of Sensory Organization and Balance (CTSIB) were assessed. Each child in the
      three study groups performed three trials and the mean value was estimated for each test.

      2.5.1. Limits of Stability test: Limits of stability are known as the furthest distance a
      subject is capable to shift his/her COP in different directions whilst keeping the
      configuration of the BOS and adjust the body position. This commonly requires the use of a
      force plate that records COP movement and a visual feedback that serves to maximize COP
      displacement in certain directions (Lemay et al., 2014). During this test, the participant is
      instructed to shift the round cursor on the screen (the COP) to the highlighted target. As
      he/she remains in the target for the hold time, this target point is deactivated and should
      move between the center targets to each surrounding target in a random order. A count-up
      timer displays the total test time. He/she must return to the center target after each outer
      target. The test was conducted at two levels 4 and 6. At level 4; this is considered as
      simple test compared with level 6; the distance between center targets to each surrounding
      target is relatively small. On the other hand, at level 6 the distance between center targets
      to each surrounding target is larger.

      2.5.2. Center of pressure test This test is used to measure the variation in a subject's COP
      and displays his/her Right/Left and Anterior/Posterior weight distribution. In the current
      study, the COP test variables recorded were the stability score and path length.

        -  Stability test: It measures the participant's ability to stabilize his/her balance at
           locations around their neutral position. Results are reported as the percent of time a
           subject holds his COP in each of the eight flashing targets in clockwise order
           (right/left and anterior/posterior weight distribution). These targets are eight
           specific points in which the current target flashes green when the participant is
           on-target and flashes yellow when he is off-target. The HUMAC system provides a
           counts-down of the hold time to inform the participant when he/she should move to the
           next target. In addition, the system provides variety of levels based on the distance
           from the center to the farthest target.

        -  Path length: The COP path length represents the COP displacement in which lower values
           indicate better performance (Ju-Hyeong et al., 2020).

      2.5.3. Clinical Test of Sensory Organization and Balance: It is sometimes referred as the
      Romberg or Foam and Dome test. It is used to test how a participant's vestibular,
      somatosensory and visual systems integrate in the conditions of open and closed eyes compared
      to a normal population. The CTSIB protocol typically uses four conditions including eyes
      closed soft surface (ECSS); eyes closed firm surface (ECFS); eyes open soft surface (EOSS);
      Eye open soft surface (EOSS) and eyes open firm surface (EOFS). The participant was
      instructed to stand in a neutral position with the arms at body sides. Each participant went
      through a series of the four tests, which were each 30 seconds long. As participants
      completed the test, the board monitored their COG to determine their stability and path
      length. The requirements of the assessment were clearly demonstrated to all children. The
      assessment procedures were administered following the HUMAC Balance System manual detailed
      instructions. All participants performed three trials of each test, each lasting 30 seconds
      to determine the stability score and path length.
    

Intervention name(s): assessment of postural stability
Intervention type(s): Other
Intervention description(s): assessment of postural stability
Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Fifty eligible volunteer children with CKD were recruited from Nephrology Unit, Zagazig
        University Hospitals to be enrolled in this study and allocated into either hemodialysis
        (on hemodialysis) or non-dialysis group (children at stage 3 and 4).
      
Keywords: Balance; Chronic kidney disease; HUMAC balance system; Postural stability