The Four Square Step Test (FSST) appears to be a valid and reliable instrument for measuring dynamic balance, falling risk, and functional levels in patients with Duchenne muscular dystrophy (DMD), according to a recently published study in the journal Developmental Neurorehabilitation.

Although the neuronal pathways responsible for sensory processing are intact in patients with DMD, in the majority of patients the musculoskeletal system is unable to produce balance-correcting forces, which makes them more likely to fall. 

“As a result, mobility, functionality, independence in activities are affected, and social participation decreases, along with the loss of balance due to muscle weakness and fear of falling,” the authors wrote.


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Therefore, there is a need for instruments that allow medical professionals to accurately assess the balance and functional levels of patients with DMD. Notably, currently available tools, such as the Pediatric Functional Reach Test, the Up and Go Test (TUG), the Pediatric Balance Scale, and the Biodex Balance System, have long implementation times, which can lead to fatigue and higher costs. 

The FSST is a time-efficient method for balance evaluation initially developed for assessing fall risk in persons who are at least 65 years of age. Since then, it has been successfully used in the assessment of balance in children with Down syndrome and cerebral palsy.

The test uses a 4-square area, in which the patient must move forward, to the right and backward, and to the left as fast as possible while facing forward and contracting both feet in each square before moving to the left. Completion time must be measured in each test.

In the present study, the performance of the FSST was compared to that of the TUG to establish its validity using the Spearman’s correlation coefficient in 50 patients with DMD. Of the 50, 44 successfully performed the FSST, giving it a feasibility of 88%. According to statistical analysis, there was a strong correlation between TUG and FSST scores.

“As a result, it was concluded that FSST is a valid, reliable, clinically safe, and feasible outcome measure in the evaluation and follow-up of dynamic balance in both clinical settings and clinical trials,” the authors concluded.

Reference

Aldirmaz E, Uğur F, Yilmaz Ö, et al. A new instrument to assess dynamic balance in children with Duchenne muscular dystrophy: Four ssquare step test and its validity, reliability, and feasibilityDev Neurorehabilit. Published online November 11, 2022. doi:10.1080/17518423.2022.2143924