Evaluation of Internal Construct Validity and Unidimensionality of the Brachial Assessment Tool, A Patient-Reported Outcome Measure for Brachial Plexus Injury

Abstract

This preliminary analysis supports the internal construct validity of the Brachial Assessment Tool, a unidimensional targeted 4-response patient-reported outcome measure designed to solely assess activity after traumatic BPI regardless of level of injury, age at recruitment, premorbid limb dominance, and time postinjury. Further examination is required to determine test-retest reliability and responsiveness.

Development of a Questionnaire to Measure Impact and Outcomes of Brachial Plexus Injury

“…Several other upper-extremity questionnaires (none specific to BPI) and various general health questionnaires also have been used 1,3,8,9,20,22 . Recently, a 31-item survey was developed for BPI to measure mechanical function of the affected limb for daily activities (e.g., put toothpaste on a toothbrush) and will be useful to track performance of these activities longitudinally 6 . Our questionnaire, in contrast, measures the impact of BPI on psychosocial life, activities of daily living, emotional aspects of recovery, and pain.…”

“…Capturing these psychological elements within a BPI disease-specific context is necessary in order to thoroughly understand disability and recovery from this complex condition. For BPI, outcomes historically have been reported on the basis of surgeon-graded muscle function; more recent efforts have incorporated functional and generic psychological questionnaires [1][2][3][4][5][6][7][8][9][10] . However, these outcomes do not simultaneously include broad perspectives of, and attention to, multiple physical and emotional aspects of life impacted by BPI over time.…”

Preliminary Psychometric Evaluation of the Brachial Assessment Tool Part 2: Construct Validity and Responsiveness

“…Data were collected concurrently for the Rasch analysis, a reliability project and this project. (12) The primary inclusion criteria for all three projects was a diagnosis of traumatic BPI confirmed by MRI, nerve conduction studies, clinical assessment or intraoperative findings, and were over 18 years of age. In contrast to the reliability arm participants were only recruited if they had undergone microsurgery to reanimate the upper limb within the previous two years.…”

“…(11) Items are important to people with BPI, regularly performed and appear to represent the spectrum of ability of this population. (8,12) The BrAT is comprised of 3 subscales: i) M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 eight 'Dressing and grooming' items, ii) 17 'Whole arm and hand' items, iii) six 'No hand' items; or alternatively all 31-items may be added to produce a summed score.…”

“…Content validity and unidimensionality of the BrAT has been established using Rasch analysis. (12) Reliability has been evaluated and a minimal detectable change score calculated for each subscale and the summed score. Further evaluation of construct validity and responsiveness is required to complete the initial psychometric testing.…”