Functional Test of the Hemiparetic Upper Extremity: A Rasch Analysis With Theoretical Implications

Abstract

Objective: To investigate the measurement properties of the Functional Test of the Hemiparetic Upper Extremity (FTHUE) and examine how its score may or may not inform design of a rehabilitation program.

Design: The FTHUE was recently used in the Interdisciplinary Comprehensive Arm Rehabilitation Evaluation randomized controlled trial. This circumstance provided the opportunity to examine the psychometric properties of the FTHUE as it pertains to contemporary poststroke rehabilitation and recovery models.

Setting: Outpatient rehabilitation clinic.

Participants: Participants (N=109; mean age, 61.2±13.5y; mean days poststroke, 46±20.3) with resultant hemiparesis in the upper extremity.

Interventions: Not applicable.

Main outcome measures: Dimensionality was examined with confirmatory factor analysis (CFA), and person and item measures were derived with Rasch item response analysis. Therapists' notes were also reviewed.

Results: The CFA results support unidimensionality, and 16 of 17 items fit the Rasch model. The Rasch person separation (2.17) and item separation (4.50) indices, ability strata (3.22), person reliability (.82), and item reliability (.95) indicate good measurement properties. Item difficulties ranked from -6.46 to 3.43 logits; however, there was a substantial ceiling effect of person measures. Post hoc examination of therapists' written observations indicated that the scoring criteria are not sensitive to the movement strategy used for task completion.

Conclusions: The FTHUE's item difficulty hierarchy indicated that scores adequately distinguished the ability to perform simple versus complex motor movements of functional tasks. However, the FTHUE scoring method did not allow inclusion of the type of movement strategy used to accomplish task items. Therefore, we suggest modifications to the FTHUE that would allow it to be used for collaborative treatment planning and align well with more contemporary perspectives on treatment theory.

Trial registration: ClinicalTrials.gov NCT00871715.

Keywords: Rehabilitation; Stroke; Upper Extremity.

Figure 1. Rasch Analysis Wright Person-Item Map

The center vertical column is the measurement metric in logit units ranging from −6.00 to 5.00. Relative to this column, people are to the left and items are to the right. People are located along the metric according to their measures of person ability so that lower ability people (low person measures) are at the bottom of the map, and higher ability people (high person measures) are at the top of the map. Each item is located along the metric according to its measure of item difficulty. The easiest items are located at the bottom of the map and the more difficult items are located at the top of the map.