Relative and absolute reliability of the new “Step-Ex” step-execution test in elderly people with and without balance problems

Abstract

Purpose: To evaluate the relative and absolute test–re-test reliability of a new step-execution test, “Step-Ex”, for clinical use in elderly with and without balance problems. Method: Test–re-test design to assess intrarater reliability. Thirty-four healthy community-dwelling elderly (65–87 years), 16 with balance problems, were tested twice two weeks apart. Step-Ex consists of two portable force platforms that register vertical ground reaction forces connected to a computer for easy detection of temporal events and phases (reaction-, preparation-, stepping- and step execution phase). Standing with one foot on each platform, the subjects were given a tactile stimulus on the heel to initiate rapid steps forward. Results: Test–re-test agreement was good to very good: ICC_2.6 0.83–0.87 (without balance problems) and 0.71–0.83 (with balance problems) with no apparent systematic differences between the tests. The SEM, i.e. the smallest detectable change that may indicate a real clinical improvement for a group of individuals was small, 4.6–8.6%. The smallest real difference, representing the smallest change that reveals clinical improvement for a single individual, was 13–24%. Conclusion: Step-Ex is a highly reliable instrument and can be recommended as an outcome measure evaluating the effects of balance training in elderly people with and without balance deficits.

Implications for Rehabilitation

• Balance deficits are common in the elderly population.

• To evaluate the effects of treatment or changes over time it is of great importance to have reliable instruments.

• Step-Ex is a highly reliable instrument and can be recommended as an outcome measure evaluating the effects of treatment or changes over time in elderly people with and without balance deficits.

Keywords::

• Aging
• balance control
• falls
• Step-Ex
• stepping

Acknowledgement

The authors thank all the participants in the study and give special thanks to Lisbet Broman at Karolinska Institutet for help and guidance with data collection and statistical analysis.

Declaration of Interest: The study was supported by grants from the Regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet, School of doctoral education in Health Care Science Stockholm, Sweden, and from the Swedish Research Council, the Torsten and Ragnar Söderberg Foundation and the Swedish Order of St. John (Johanniterorden). We certify that no party having a direct interest in the results of the research supporting this article has or will confer a benefit on us or on any organization with which we are associated AND, if applicable, we certify that all financial and material support for this research (e.g. NIH or NHS grants) and work are clearly identified in the title page of the manuscript.