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.