Test-retest reliability of static and dynamic motor fatigability protocols using grip and pinch strength in typically developing children.

Upper limb motor fatigability is an important debilitating factor for activities of daily living in clinical pediatric populations. However, the reliability of fatigability protocols in these populations is currently unknown. Therefore, the current study investigates test-retest reliability of a static and dynamic motor fatigability protocol for grip and pinch strength in typically developing children (TDC). Eighty-nine TDC (35 boys, 54 girls; mean age 10 years 11 months) used a grip and pinch dynamometer for static (sustained) and dynamic (repeated) contractions during 30s. For static motor fatigability (SFI), mean (Fmean) and SD (Fvar) of force were calculated, and for dynamic motor fatigability, F mean and number of peaks (Npeaks) were calculated. Intraclass correlation coefficients (ICC) were calculated. ICCs of F mean in static and dynamic motor fatigability were high (ICC: 0.94-0.96 and 0.91-0.98). ICCs were moderate to high for F var (ICC: 0.67-0.85). The SFI showed moderate ICCs (ICC: 0.69-0.77). ICCs were moderate to high for N peaks (ICC: 0.78-0.91).Conclusion: The results suggest that static and dynamic motor fatigability in for grip and pinch can be used reliably in TD children aged 6-18 years. What is Known: •Psychometric properties of motor fatigability protocols using grip and pinch in children are lacking. •Motor fatigability in grip and pinch is an important debilitating symptom in multiple neurologic populations. What is New: •Static fatigability can be investigated using a 30-s maximum sustained grip strength protocol in children. •Dynamic fatigability can be investigated using a 30-s maximum repeated grip strength protocol in children.

Measuring Motor Fatigability in the Upper Limbs in Individuals With Neurologic Disorders: A Systematic Review.

OBJECTIVE: To summarize the literature on definitions, assessment protocols, and outcome measures for motor fatigability in patients with neurologic problems and investigates the known clinimetric properties according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria. DATA SOURCES: Two databases were consulted for studies published between January 2003 and November 2018 using the terms "motor fatigability," "nervous system disease," and "upper limb." STUDY SELECTION: Studies were included if they were (1) not older than 15 years; (2) written in English, German, or Dutch; (3) involved upper limbs of patients with neurologic disease; and (4) adequately described protocols using maximum voluntary contractions. DATA EXTRACTION: Thirty-three studies were included, describing 14 definitions, 37 assessment protocols, and 9 outcome measures. The following data were obtained: (1) author and publication year; (2) aim; (3) fatigability definition; (4) sample characteristics; (5) fatigability protocol; (8) measurement system; and (9) outcome measure. DATA SYNTHESIS: Protocols relating to body function level of the International Classification of Functioning (ICF) were most often performed in patients with multiple sclerosis (MS) including maximal or submaximal, isometric or concentric, and eccentric contractions of variable duration. For ICF activities level, most protocols included wheelchair-related tasks. Clinimetric properties were known in 2 included protocols. Test-retest reliability in patients with MS were moderate to excellent for the static fatigue index and moderate for the dynamic fatigue index. CONCLUSIONS: Based on physiology, recommendations are made for protocols and outcome measures for motor fatigability at the ICF body function level. For the ICF activities level, too little is known to make sound statements on the use of protocols in populations with neurologic disease. Clinimetric properties should be further investigated for populations with neurologic problems.

Children With Cerebral Palsy Show Higher Static-But Not Higher Dynamic-Motor Fatigability in Grip and Pinch Tasks Than Children With Typical Development Do.

OBJECTIVE: The purpose of this study was to investigate differences in static and dynamic motor fatigability during grip and pinch tasks between children with unilateral spastic cerebral palsy (USCP) and children with typical development (TD) and between preferred and nonpreferred hands. METHODS: Fifty-three children with USCP and 53 age-matched children with TD (mean = 11 years 1 month; SD = 3 years 8 months) participated in 30-second maximum exertion sustained and repeated grip and pinch tasks. For sustained tasks, the Static Fatigue Index and the ratio of mean force between the first and last thirds of the curve were calculated. For repeated tasks, the ratio of mean force and the ratio of numbers of peaks between the first and last thirds of the curve were calculated. RESULTS: Higher Static Fatigue Index scores for grip and pinch were found with USCP in both hands and between hands in both groups. Dynamic motor fatigability showed inconsistent results, with higher levels of fatigability in children with TD than in children with USCP for grip in the ratio of mean force between the first and last thirds of the curve in nonpreferred hands and in the ratio of number of peaks between the first and last thirds of the curve in preferred hands. CONCLUSION: Higher motor fatigability in children with USCP than in children with TD was found for static but not dynamic grip and pinch. Underlying mechanisms may play different roles in static and dynamic motor fatigability. IMPACT: These results highlight that static motor fatigability in grip and pinch tasks should be part of a comprehensive upper limb assessment and that this could be the target of individualized interventions.

Test-Retest Reliability of a Static and Dynamic Motor Fatigability Protocol Using Grip and Pinch Strength in Children With Cerebral Palsy.

OBJECTIVE: The purpose of this study was to investigate the test-retest reliability, measurement error, and interpretability of new motor fatigability outcomes of grip and pinch strength for children with unilateral cerebral palsy (UCP). METHODS: Motor fatigability during grip and pinch strength was measured twice (within 48 hours) in both hands of 50 children (mean age = 11 years 2 months; 14, 31, and 5 children with Manual Ability Classification System levels I, II, and III, respectively) using a 30-second static and dynamic maximum exertion protocol. For static motor fatigability, the Static Fatigue Index (SFI) and mean force (Fmean) in the first (Fmean1) and last (Fmean3) 10 seconds were calculated. For dynamic motor fatigability, Fmean1, Fmean3, and the number of peaks in the first and last 10 seconds were calculated. RESULTS: For static motor fatigability, the intraclass correlation coefficients (ICCs) were moderate to high for Fmean1 and Fmean3 (0.56-0.88), and the SFI showed low to moderate reliability (ICC = 0.32-0.72). For dynamic motor fatigability, the ICCs were moderate to high for all outcomes (0.54-0.91). The standard error of measurement agreement and the smallest detectable difference agreement were large in all outcomes, except for the SFI in static motor fatigability. Details per age group are provided. In general, younger children (6-11 years old) showed lower reliability than older children (12-18 years old). CONCLUSION: Most outcome measures for static and dynamic motor fatigability of grip and pinch strength show moderate to high reliability in children with UCP, indicating that these tests can be used reliably to investigate the presence of motor fatigability in UCP, especially in older children. Standard error of measurement agreement and smallest detectable difference agreement indicated that these outcome measures should be interpreted with caution when evaluating change. IMPACT: Most of the proposed outcome measures for static and dynamic motor fatigability of grip and pinch are reliable in children with UCP and can be used for discriminative purposes.