Spasticity, an impairment that is poorly defined and poorly measured

Area of Science:

• Neurology
• Rehabilitation Medicine
• Biomedical Research

Background:

• Spasticity is a common motor disorder following neurological injury, characterized by velocity-dependent muscle tone increase.
• Existing literature reveals a lack of consensus regarding the definition and assessment of spasticity.
• This ambiguity impacts the reliability and comparability of research findings in the field.

Purpose of the Study:

• To systematically review the literature and identify a consistent definition of spasticity.
• To determine if a unified assessment framework for spasticity exists.
• To explore the congruence between spasticity definitions and measurement methods.

Main Methods:

• A systematic literature search was conducted across major electronic databases (Web of Science, Science Direct, MEDLINE).
• Publications in English from 1980 to 2006 were reviewed using keywords: spasticity, tone, stroke, hemiplegia, upper, hand, and arm.
• A total of 250 references, including clinical trials, literature reviews, and case reports, were analyzed.

Main Results:

• The term 'spasticity' was inconsistently defined, with 78 studies using the Lance definition, 88 equating it with increased muscle tone, and 78 providing no definition.
• Measurement methods often lacked congruence with the defined clinical features of spasticity, compromising internal validity.
• A variety of assessment methods were employed, including neurophysiological, biomechanical, and clinical measures, with limited explicit description in some studies.

Conclusions:

• The definition and assessment of spasticity are inconsistent across the scientific literature.
• There is a critical need to resolve definitional ambiguities and establish a unified framework for spasticity assessment.
• Future research must ensure congruence between spasticity definitions and measurement techniques to improve study validity and clinical relevance.