# TRANSLATION, RELIABILITY, AND VALIDITY OF THE TRUNK IMPAIRMENT SCALE IN A POLISH POPULATION AFTER STROKE

## TL;DR

This study confirms that the Polish version of the Trunk Impairment Scale is reliable and moderately valid for assessing trunk function in stroke survivors.

## Contribution

The study provides a culturally adapted and validated Polish version of the Trunk Impairment Scale for post-stroke assessment.

## Key findings

- The Polish version of the Trunk Impairment Scale showed excellent internal consistency and almost perfect test–retest and inter-rater reliability.
- Construct validity was moderate, and a moderate correlation was found between trunk function and upper limb physical function.
- Trunk function is moderately related to gross and fine motor skills of the arm, hand, and fingers among individuals with stroke.

## Abstract

This study was conducted to estimate the reliability and validity of the translated and culturally adapted Polish version of the Trunk Impairment Scale in post-stroke patients and to determine the strength of the relationship between trunk and upper limb physical function after stroke.

The Polish version of the Trunk Impairment Scale was developed through cultural adaptation. Internal consistency, test–retest reliability, and inter-rater reliability were determined, and construct validity was evaluated by analysing the Polish version of the Trunk Impairment Scale, the Polish version of the Fugl-Meyer Assessment Scale, and the Polish version of the Action Research Arm Test.

Eighty patients with diagnosed stroke in the subacute and chronic stages.

The internal consistency for the Polish version of the Trunk Impairment Scale was excellent (α = 0.85–0.91). Test–retest and inter-rater reliability were almost perfect (ICC = 0.94–1.0, κ = 0.92–1.0). Construct validity was moderate (rho = 0.71–0.76). A moderate correlation was also found between the Polish version of the Trunk Impairment Scale and Polish version of the Action Research Arm Test total scores (rho = 0.60).

The Polish version of the Trunk Impairment Scale is a reliable and moderately valid outcome measure to assess trunk impairment in Polish stroke survivors. Trunk function is moderately related to gross and fine motor skills of the arm, hand, and fingers among individuals with stroke.

Two primary objectives were pursued in this study. The first aim was to evaluate the diagnostic utility of the newly developed Polish version of the Trunk Impairment Scale. The second was to examine the relationship between trunk and upper extremity function. A total of 80 post-stroke participants were enrolled. The Trunk Impairment Scale was translated into Polish, and subsequently, the reliability and validity of the Polish version of the Trunk Impairment Scale were calculated. Furthermore, the correlation between the Polish version of the Trunk Impairment Scale and the Polish version of the Action Research Arm Test was analysed. The results showed that the Polish version of the Trunk Impairment Scale is a highly reliable and moderately valid outcome measure for assessing individuals in the Polish population after stroke. Moreover, a moderate relationship between trunk function and upper extremity activity was demonstrated.