Theoretical and methodological considerations in the measurement of spasticity

PURPOSE: To discuss the measurement of spasticity in the clinical and research environments, make recommendations based on the SPASM reviews of biomechanical, neurophysiological and clinical methods of measuring spasticity and indicate future developments of measurement tools. METHOD: Using the results of the systematic reviews of the biomechanical, neurophysiological and clinical approaches, methods were evaluated across three dimensions: (1) validity, reliability and sensitivity to change; (2) practical quality such as ease of use and (3) qualities specific to the measurement of spasticity, for example ability to be applied to different muscle groups. Methods were considered in terms of applicability to research and clinical applications. RESULTS: A hierarchy of measurement approaches was identified from highly controlled and more objective (but unrelated to function) to ecologically valid, but less objective and subject to contamination from other variables. The lack of a precise definition of spasticity may account for the problem of developing a valid, reliable and sensitive method of measurement. The reviews have identified that some tests measure spasticity per se, some phenomena associated with spasticity or consequential to it and others the effect of spasticity on activity and participation and independence. CONCLUSIONS: Methods appropriate for use in research, particularly into the mechanism of spasticity did not satisfy the needs of the clinician and the need for an objective but clinically applicable tool was identified. A clinical assessment may need to generate more than one 'value' and should include evaluation of other components of the upper motor neurone syndrome. There is therefore a need for standardized protocols for 'best practice' in application of spasticity measurement tools and scales.     

Theoretical and methodological considerations in the measurement of spasticity

Purpose: To discuss the measurement of spasticity in the clinical and research environments, make recommendations based on the SPASM reviews of biomechanical, neurophysiological and clinical methods of measuring spasticity and indicate future developments of measurement tools. Method: Using the results of the systematic reviews of the biomechanical, neurophysiological and clinical approaches, methods were evaluated across three dimensions: (1) validity, reliability and sensitivity to change; (2) practical quality such as ease of use and (3) qualities specific to the measurement of spasticity, for example ability to be applied to different muscle groups. Methods were considered in terms of applicability to research and clinical applications. Results: A hierarchy of measurement approaches was identified from highly controlled and more objective (but unrelated to function) to ecologically valid, but less objective and subject to contamination from other variables. The lack of a precise definition of spasticity may account for the problem of developing a valid, reliable and sensitive method of measurement. The reviews have identified that some tests measure spasticity per se, some phenomena associated with spasticity or consequential to it and others the effect of spasticity on activity and participation and independence. Conclusions: Methods appropriate for use in research, particularly into the mechanism of spasticity did not satisfy the needs of the clinician and the need for an objective but clinically applicable tool was identified. A clinical assessment may need to generate more than one 'value' and should include evaluation of other components of the upper motor neurone syndrome. There is therefore a need for standardized protocols for 'best practice' in application of spasticity measurement tools and scales.     

Neurophysiological methods for the assessment of spasticity: The Hoffmann reflex, the tendon reflex, and the stretch reflex

Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological - biomechanical assessment of spasticity during active, functional movement.     

Biomechanical approaches applied to the lower and upper limb for the measurement of spasticity: A systematic review of the literature

Purpose: To review and characterise biomechanical approaches for the measurement of spasticity as one component of the upper motor neurone syndrome. Method: Systematic literature searches based on defined constructs and a four-step review process of approaches used or described to measure spasticity, its association with function or associated phenomena. Most approaches were limited to individual joints and therefore, to reflect this trend, references were grouped according to which body joint(s) were investigated or whether it addressed a functional activity. For each joint, references were further sub-divided into the types of measurement method described. Results: A database of 335 references was established for the review process. The knee, ankle and elbow joints were the most popular, perhaps reflecting the assumption that they are mono-planar in movement and therefore simpler to assess. Seven measurement methods were identified: five involving passive movement (manual, controlled displacement, controlled torque, gravitational and tendon tap) and two involving active movement (voluntary and functional). Generally, the equipment described was in an experimental stage and there was a lack of information on system properties, such as accuracy or reliability. Patient testing was either by cohort or case studies. The review also conveyed the myriad of interpretations of the concept of spasticity. Conclusions: Though biomechanical approaches provide quantitative data, the review highlighted several limitations that have prevented them being established as an appropriate method for clinical application to measure spasticity.     

Clinical measurement of postural control in adults

Postural control is the ability to maintain equilibrium and orientation in a gravitational environment. Effective approaches for clinical measurement of postural control remain to be developed. This article summarizes important neurophysiological and clinical considerations for developing measurement tools to assess postural control in adults. The postural control system is divided into three basic functional components for assessment: 1) biomechanical components, 2) motor coordination components, and 3) sensory organization components.     

Pain outcomes: A brief review of instruments and techniques

Pain is a difficult outcome to measure due to its multifaceted and subjective nature. The need for selecting proper outcome measures is high because of the increasing demand for scientifically valid demonstrations of treatment efficacy. This article discusses some basic topics in the measurement of pain outcomes and addresses issues such as statistical versus clinical significance, daily home data collection, appropriate length of outcome measurement packets, and the possibility of objective pain measurements. This article also reviews some of the more commonly used tools for measuring pain and pain-related disability. By selecting the proper tools and employing them correctly, we can obtain highly reliable and valid measures of pain outcomes in research and clinical care.     

Neurophysiological methods for the assessment of spasticity: The Hoffmann reflex,the tendon reflex,and the stretch reflex

Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological?-?biomechanical assessment of spasticity during active, functional movement.     

Biomechanical approaches applied to the lower and upper limb for the measurement of spasticity: a systematic review of the literature

PURPOSE: To review and characterise biomechanical approaches for the measurement of spasticity as one component of the upper motor neurone syndrome. METHOD: Systematic literature searches based on defined constructs and a four-step review process of approaches used or described to measure spasticity, its association with function or associated phenomena. Most approaches were limited to individual joints and therefore, to reflect this trend, references were grouped according to which body joint(s) were investigated or whether it addressed a functional activity. For each joint, references were further sub-divided into the types of measurement method described. RESULTS: A database of 335 references was established for the review process. The knee, ankle and elbow joints were the most popular, perhaps reflecting the assumption that they are mono-planar in movement and therefore simpler to assess. Seven measurement methods were identified: five involving passive movement (manual, controlled displacement, controlled torque, gravitational and tendon tap) and two involving active movement (voluntary and functional). Generally, the equipment described was in an experimental stage and there was a lack of information on system properties, such as accuracy or reliability. Patient testing was either by cohort or case studies. The review also conveyed the myriad of interpretations of the concept of spasticity. CONCLUSIONS: Though biomechanical approaches provide quantitative data, the review highlighted several limitations that have prevented them being established as an appropriate method for clinical application to measure spasticity.     

Neurophysiological methods for the assessment of spasticity: the Hoffmann reflex, the tendon reflex, and the stretch reflex

PURPOSE: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). METHOD: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. RESULTS: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. CONCLUSIONS: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological-biomechanical assessment of spasticity during active, functional movement.     

Biomechanical approaches applied to the lower and upper limb for the measurement of spasticity: A systematic review of the literature

Purpose: To review and characterise biomechanical approaches for the measurement of spasticity as one component of the upper motor neurone syndrome. Method: Systematic literature searches based on defined constructs and a four-step review process of approaches used or described to measure spasticity, its association with function or associated phenomena. Most approaches were limited to individual joints and therefore, to reflect this trend, references were grouped according to which body joint(s) were investigated or whether it addressed a functional activity. For each joint, references were further sub-divided into the types of measurement method described. Results: A database of 335 references was established for the review process. The knee, ankle and elbow joints were the most popular, perhaps reflecting the assumption that they are mono-planar in movement and therefore simpler to assess. Seven measurement methods were identified: five involving passive movement (manual, controlled displacement, controlled torque, gravitational and tendon tap) and two involving active movement (voluntary and functional). Generally, the equipment described was in an experimental stage and there was a lack of information on system properties, such as accuracy or reliability. Patient testing was either by cohort or case studies. The review also conveyed the myriad of interpretations of the concept of spasticity. Conclusions: Though biomechanical approaches provide quantitative data, the review highlighted several limitations that have prevented them being established as an appropriate method for clinical application to measure spasticity.     

Assessment of spasticity after stroke using clinical measures: a systematic review

Abstract

Purpose: To identify and appraise the literature on clinical measures of spasticity that has been investigated in people after stroke. Methods: The literature search involved four databases (PubMed, CINAHL, Embase and The Cochrane Library) up to February 2014. The selected studies included those that aimed to measure spasticity using a clinical assessment tool among adult patients post-stroke. Two independent raters reviewed the included articles using a critical appraisal scale and a structured data extraction form. Results: A total of 40 studies examining 15 spasticity assessment tools in patients post-stroke were reviewed. None of the reviewed measurement tools demonstrated satisfactory results for all psychometric properties evaluated, and the majority lacked evidence concerning validity and absolute reliability. Conclusion: This systematic review found limited evidence to support the use of most of clinical measures of spasticity for people post-stroke. Future research examining the application and psychometric properties of these measures is warranted.

• Implications for Rehabilitation

• There is a need for objective clinical tools for measuring spasticity that are clinically feasible and easily interpreted by clinicians.

• This review identified various clinical measures of spasticity that have been investigated in people after stroke.

• Insufficient evidence of psychometric properties precludes recommending one tool over the others.

• Future research should focus on investigating the psychometric properties of clinical measures of spasticity.

     

Clinometric properties of a clinical spasticity measurement tool

PURPOSE: To investigate clinometric properties of an Anglo-Dutch spasticity measurement tool (ADSMT), an objective tool providing information about both neurophysiological and biomechanical aspects of spasticity about the wrist joint in the clinical setting. METHOD: ADSMT measurements were performed with 12 healthy and 11 participants with post-stroke spasticity, and consisted of assessing the maximum range of passive wrist movement (pROM) and passive wrist extension at different cycle rates. Outcome measures were wrist angle, flexor and extensor activation, and resistance to movement. Intra-class Correlation Coefficients (ICCs) were calculated for inter-rater and test-retest reliability. Validity was investigated by calculating Spearman's rho between ADSMT outcome measures and the Modified Ashworth Scale (n=12), the Action Research Arm Test (n=6), and a validated wrist rig (n=6). RESULTS: Impaired participants had higher flexor activity and higher resistance to movement during passive wrist extension compared to unimpaired participants. For all outcome measures inter-rater and test-retest reliability were satisfactory to good and concurrent validity was sufficient. CONCLUSIONS: Outcome measures related to wrist flexor activity and resistance to movement during extension are promising for spasticity assessment using the ADSMT. Further knowledge on reference values and practicality is necessary for this tool to become incorporated in the clinical setting.     

Biomechanical examination of a commonly used measure of spasticity

Background. An increase in the prevalence of neurological disability puts pressure on service providers to restrict costs associated with rehabilitation. Spasticity is an important neurological impairment for which many novel and expensive treatment options now exist. The antispastic effects of these techniques remain unexplored due to a paucity of valid outcome measures.

Aim. To develop a biomechanical measure of resistance to passive movement, which could be used in routine clinical practice, and to examine the validity of the modified Ashworth scale.

Study design. Repeated measure cross-section study on 16 subjects who had a unilateral stroke one-week previously and had no elbow contractures.

Outcome measures. Simultaneous measurement of resistance to passive movement using a custom built measuring device and the modified Ashworth scale. Passive range of movement and velocity were also measured. The “catch”, a phenomenon associated with the modified Ashworth scale, was identified by the assessor using a horizontal visual analogue scale and biomechanically quantified using the residual calculated from a linear regression technique.

Results. Half the study population had a modified Ashworth score greater than zero. The association between the two measures was poor (κ=0.366). The speed and range of passive movement were greater in subjects with modified Ashworth score “0” (P<0.05). Resistance to passive movement was higher in the impaired arm (P<0.05) and tended to decrease with repeated measures and increasing speeds.

Conclusions. A device to measure resistance to passive movement at the elbow was developed. The modified Ashworth scale may not provide a valid measure of spasticity but a measure of resistance to passive movement in an acute stroke population.Relevance

Spasticity is an important neurological impairment for which many novel and expensive treatment options are being made available. There is a paucity of clinically usable outcomes to measure spasticity. A device to measure resistance to passive movement at the elbow, which was more reliable than the modified Ashworth scale was developed. This device may provide a much needed objective clinical measure to evaluate the efficacy of antispasticity treatment.     

Clinometric properties of a clinical spasticity measurement tool

Purpose. To investigate clinometric properties of an Anglo-Dutch spasticity measurement tool (ADSMT), an objective tool providing information about both neurophysiological and biomechanical aspects of spasticity about the wrist joint in the clinical setting.

Method. ADSMT measurements were performed with 12 healthy and 11 participants with post-stroke spasticity, and consisted of assessing the maximum range of passive wrist movement (pROM) and passive wrist extension at different cycle rates. Outcome measures were wrist angle, flexor and extensor activation, and resistance to movement. Intra-class Correlation Coefficients (ICCs) were calculated for inter-rater and test-retest reliability. Validity was investigated by calculating Spearman's rho between ADSMT outcome measures and the Modified Ashworth Scale (n = 12), the Action Research Arm Test (n = 6), and a validated wrist rig (n = 6).

Results. Impaired participants had higher flexor activity and higher resistance to movement during passive wrist extension compared to unimpaired participants. For all outcome measures inter-rater and test-retest reliability were satisfactory to good and concurrent validity was sufficient.

Conclusions. Outcome measures related to wrist flexor activity and resistance to movement during extension are promising for spasticity assessment using the ADSMT. Further knowledge on reference values and practicality is necessary for this tool to become incorporated in the clinical setting.     

Clinical scales for the assessment of spasticity, associated phenomena, and function: a systematic review of the literature

Purpose: To characterise clinical assessment methods for spasticity and/or its functional consequences in clinical patient populations at risk to suffer from spasticity. Method: Systematic literature search and manual-based two-step review process of psychometric properties of clinical assessment scales for spasticity and associated phenomena, as well as of functional scales with an association with spasticity. Reviewed psychometric properties included internal consistency, interrater, intrarater as well as retest reliability, construct validity, ecological validity, and responsiveness. Results: Until May 2003 electronic database searches established a reference pool of 4151 references of which 90 references contributed to the review objectives. An additional 20 references were identified by an informal reference search. Twenty-four clinical scales that assess spasticity and/or related phenomena as well as 10 scales for 'active function' and three scales for 'passive function' with an association with spasticity could be identified. Some evidence signals that a high interrater reliability of the Ashworth and modified Ashworth scales can be achieved, however not in all circumstances. For many scales, reliability data is, however, missing. This is especially true for test retest reliability. Information about construct validity can promote our understanding of what individual scales are likely to assess. Many scales have been able to document changes after therapeutic intervention. Conclusions: The collated evidence can guide our clinical decision about when to use which scale and can promote evidence-based assessment of spasticity and related clinical phenomena.     

Dorsal rhizotomy for children with cerebral palsy: support for concepts of motor control

The results from selective dorsal rhizotomy research suggest that therapists need to question some common clinical assumptions about movement dysfunction. The rationale for performing a selective dorsal rhizotomy is based on the clinical assumptions that spasticity is the underlying cause of disordered movement and that reducing or eliminating the spasticity will improve movement. This article reviews the literature related to movement dysfunction, the effects of selective dorsal rhizotomy, and the evidence for disordered motor control in children with spastic cerebral palsy. Selective dorsal rhizotomy appears to reduce spasticity and increase joint range of motion. Abnormal movement patterns, however, persist after the spasticity is reduced. Well-coordinated movement patterns are acquired slowly and appear to be related to an intense period of physical therapy. I argue that these results provide evidence that the presence of spasticity alone is an insufficient explanation for abnormal movement patterns. I propose that physical therapists redirect their efforts from developing methods for reducing spasticity to developing adequate assessment, treatment, and measurement techniques for assessing motor control in children with cerebral palsy. I believe we can maximize the functional potential of children with cerebral palsy by identifying problems related to motor control and applying sound principles of motor learning to treatment.     

Biomechanics of reaching: clinical implications for individuals with acquired brain injury

Purpose : Outline the biomechanics of reaching both in healthy individuals and in individuals with acquired brain injury (ABI), and to discuss the clinical implications for using valid biomechanical models to assess reaching.

Methods : A review of current literature, including a MEDLINE search using keywords of reaching, ABI, stroke, biomechanics and motor control.

Results : Current assessments of the upper extremity in ABI are focused on single-joint characteristics of range of motion, strength and spasticity. However, reaching is a functional multijoint task requiring interjoint coordination in addition to feedback and feedforward control to position the hand optimally at a desired location so that it may interact with the environment. From the literature, biomechanical measures of reaching such as movement time, movement distance and interjoint coordination have been shown to discriminate changes to hand path quality following brain injury. These measures have also been shown to correlate with measures of sensorimotor function (e.g. Fugl-Meyer) in the upper extremity.

Conclusions : Further development of reliable and valid multi-joint biomechanical evaluations is required, particularly for natural and goal-oriented reaching movements. The biomechanical assessment of reaching in ABI can provide an understanding of the specific deficits in physiological structures or motor planning underlying altered reaching ability, assist in the evaluation of new therapies, and characterize the recovery process following ABI.     

Predictors of upper limb spasticity after stroke? A systematic review and meta-analysis

ObjectiveTo determine the predictive markers for the occurrence of upper limb spasticity in the first 12 months after stroke.Data sourcesA systematic review was undertaken of the databases MEDLINE, EMBASE, CINAHL and PEDRO to 31st December 2017.Study selectionNon-experimental or experimental studies that included a control group with spasticity who did not receive an experimental intervention which investigated at least one variable (explanatory variable) measured at baseline against the development (or not) of spasticity at a future time point within 12 months post stroke were selected independently by two reviewers. Eleven papers met the selection criteria.Study appraisalData were extracted into tabular format using predefined data fields by two reviewers. Study quality was evaluated using the modified Downs and Black tool. Data were analysed using a meta-analysis or narrative review.ResultsTen studies, including 856 participants were analysed. The predictive markers of upper limb spasticity at one month post stroke were: motor 11.25 (odds ratio, OR); [95% CI:2.48, 51.04] and sensory impairments 4.91 (OR); [1.24, 19.46]; haemorrhagic stroke 3.70 (OR); [1.05, 12.98] and age 0.01 (OR) [0.00, 69.89]. Only motor impairment was found as a significant predictor at six months post stroke 30.68 (OR); [1.60, 587.06].LimitationsLow number of studies exploring biomechanical and neurophysiological in addition to behavioural predictors of spasticity were included.Conclusion and implications of key findingsUsing the results, the identified predictive markers have potential to better inform clinical decision-making and to plan specific rehabilitation interventions by physiotherapists for stroke survivors with upper limb spasticity.
Systematic Review Registration Number PROSPERO (ID: CRD42016027642).     

The gap between clinical gaze and systematic assessment of movement disorder after stroke

ABSTRACT: BACKGROUND: Movement disorders after stroke are still captured by clinical gaze and translated to ordinal scores of low resolution. There is a clear need for objective quantification, with outcome measures related to pathophysiological background. Neural and non-neural contributors to joint behavior should be separated using different measurement conditions (tasks) and standardized input signals (force, position and velocity). METHODS: We reviewed recent literature for the application of biomechanical and/or elektromyographical (EMG) outcome measures under various measurement conditions in clinical research. RESULTS: Since 2005, 36 articles described the use of biomechanical and/or EMG outcome measures to quantify post-stroke movement disorder. Nineteen of the articles strived to separate neural and non-neural components. Only 6 of the articles measured biomechanical and EMG outcome measures simultaneously, while applying active and passive tasks and multiple velocities. CONCLUSION: The distinction between neural and non-neural components to separately assess paresis, stiffness and muscle overactivity is not commonplace yet, while a large gap is to be bridged to attain reproducible and comparable results. Pathophysiologically clear concepts, substantiated with a comprehensive and concise measuring protocol will help professionals to identify and treat limiting factors in movement capabilities of post-stroke patients.     

A systematic review of the Tardieu Scale for the measurement of spasticity

Background. The Tardieu Scale has been suggested a more appropriate clinical measure of spasticity than the Ashworth or modified Ashworth Scales. It appears to adhere more closely to Lance's definition of spasticity as it involves assessment of resistance to passive movement at both slow and fast speeds.

Objective. To review the available literature in which the Tardieu Scale has been used or discussed as a measure of spasticity, with a view to determining its validity and reliability.

Study design. A systematic review of all literature found related to the Tardieu Scale (keywords: Tardieu scale, spasticity) from Pubmed and Ovid databases, including medline, CINAHL, EMBASE, Journals at Ovid full text, EBM reviews and Cochrane database of systematic reviews. Hand searching was also used to track the source literature.

Conclusions. In theory, we can acknowledge that the Tardieu Scale does, in fact, adhere more closely to Lance's definition of spasticity. However, there is a dearth of literature investigating validity and reliability of the scale. Some studies have identified the Tardieu Scale to be more sensitive than other measures, to change following treatment with botulinum toxin. Further studies need to be undertaken to clarify the validity and reliability of the scale for a variety of muscle groups in adult neurological patients.