Test-retest Reliability and Precision of the Rotterdam Intrinsic Hand Myometer.

PURPOSE: The purpose of this study was to determine the test-retest reliability and precision of Rotterdam Intrinsic Hand Myometer (RIHM) in healthy adults. METHODS: Twenty-nine participants originally recruited via convenience sampling at a Midwestern state fair returned approximately 8 days later for retest. An average of three trials for each of the five intrinsic hand strength measurements were collected using the same technique that was used during initial testing. Test-retest reliability was assessed using the intraclass correlation coefficient or ICC(2,3) and precision was evaluated using the standard error of measurement (SEM), and the minimal detectable change (MDC90)/MDC%. RESULTS: Across all measures of intrinsic strength, the RIHM and its standardized procedures had excellent test-retest reliability. Index finger metacarpophalangeal flexion demonstrated the lowest reliability, and right small finger abduction, left thumb carpometacarpal abduction, and index finger metacarpophalangeal abduction tests had the highest reliability. Precision, as evidenced by SEM and MDC values, was excellent for tests of left index and bilateral small finger abduction strength and acceptable for all other measurements. CONCLUSIONS: Test-retest reliability and precision of RIHM across all measurements was excellent. CLINICAL RELEVANCE: These findings indicate that RIHM is a reliable and precise tool in measuring intrinsic strength of hands of healthy adults, although further research is needed in clinical populations.

Age- and gender-stratified adult myometric reference values of isometric intrinsic hand strength.

STUDY DESIGN: Descriptive normative. INTRODUCTION: Intrinsic hand strength can be impacted by hand arthritis, peripheral nerve injuries, and spinal cord injuries. Grip dynamometry does not isolate intrinsic strength, and manual muscle testing is not sensitive to change in grades 4 and 5. The Rotterdam Intrinsic Hand Myometer is a reliable and valid test of intrinsic hand strength; however, no adult normative data are available. PURPOSE OF THE STUDY: To describe age- and gender-stratified intrinsic hand strength norms in subjects aged 21 years and above and to determine if factors known to predict grip dynamometry also predict measures of intrinsic hand strength. METHODS: Three trials of 5 measures of maximal isometric intrinsic strength were performed bilaterally by 607 "healthy-handed" adult males and females. Average strength values were stratified by age and gender. Data were analyzed to determine the influence of demographic and anthropometric variables on intrinsic strength. RESULTS: Intrinsic strength generally followed age and gender trends similar to grip dynamometry. Age, gender, body mass index, and the interaction between gender and body mass index were predictors of intrinsic strength, whereas in most cases, the hand being tested did not predict the intrinsic strength. DISCUSSION: With the addition of these findings, age- and gender-stratified hand intrinsic strength norms now span from age 4 through late adulthood. Many factors known to predict grip dynamometry also predict intrinsic myometry. Additional research is needed to evaluate the impact of vocational and avocational demands on intrinsic strength. CONCLUSIONS: These norms can be referenced to evaluate and plan hand therapy and surgical interventions for intrinsic weakness.