Assesment of Post-stroke Elbow Flexor Spasticity in Response to Passive Stretch in Different Forearm Positions
Conditions: Post-stroke Elbow Spasticity
Sponsor: Izmir Katip Celebi University

Assesment of Post-stroke Elbow Flexor Spasticity in Response to Passive 
Stretch in Different Forearm Positions  
 
 
Brief Title: Assesment of post-stroke elbow flexor spasticity in different forearm  
                    positions 
 
 
Protocol ID: 21.02.2018-84 
 
 
 
Date of the document: February 21, 2018 
 
 
 
 
 
 
 
 
 
 

Background 
Determination of which muscle is more spastic before injection of the botulinum toxin, and 
subsequently the application of the targeted treatment to that muscle is expected to result in more 
improvement in stroke patients with spasticity. From the view of point of post-stroke elbow 
flexor spasticity, there are three main muscles that contribute to spasticity; musculus biceps 
brachii, musculus brachialis and musculus brachioradialis (1). However, there are conflicting 
results regarding which muscle or muscles should be selected as treatment target in post-stroke 
elbow spasticity (2,3). Here the question is how to select the right muscle.The superficiality of 
the biceps brachii muscle makes it an easy target for botulinum toxin injection (2). In dynamic 
electromyography studies, it has been reported that brachioradialis muscle is the most common 
contributor one to elbow flexion spasticity, followed by biceps brachii muscle (3). In the 
diagnostic selective nerve blocks, the brachialis muscle has been reported to be foreground (2). 
It is known that the muscles that flex elbow in healthy individuals change according to forearm 
position (4). While the biceps brachii flexes the forearm in supination, the brachioradialis flexes 
the forearm in the neutral position. The brachialis muscle acts as a primary flexor muscle when 
the forearm is in pronation, but it flexes the elbow in all forearm positions (4). In the light of this 
anatomical and biomechanical knowledge, can the target muscle be selected by examination 
instead of other methods such as electromyography where equipment is required and the 
evaluation period is relatively long? Can semi-quantitative methods such as Modified Ashwort 
Scale (MAS) (5) and Modified Tardieu Scale (MTS) (6) be used to assess the severity of 
spasticity provide reliable information regarding the muscle or muscles that contribute to elbow 
flexor spasticity? In this study, hypothesis is that the severity of  the post-stroke elbow spasticity 

differs depending on the forearm position that is one of the determinants which elbow flexor 
muscle to be more active in healthy subjects. 
Aim 
The aim of this study is to investigate whether the severity of spasticity differs depending on the 
forearm position. 
Methods 
Study design 
This study is a single group, observational and cross-sectional study. Participants who meet the 
inclusion criteria and  give written informed consent will be included in the study. This study was 
approved by the non-interventional Ethics Committee of Faculty of Medicine of İzmir Katip 
Çelebi University with approval number of 21.02.2018-84.  
Setting 
Subjects will be recruited based on identification of stroke patients with elbow flexor spasticity 
who present to outpatient or inpatient clinics of Physical Medicine and Rehabilitation (PMR) 
Department of İzmir Katip Çelibi University Atatürk Training and Research Hospital. All 
assessments will also be performed at the department of PMR of İzmir Katip Çelibi University 
Atatürk Training and Research Hospital. 
Selection criteria 
First the physician will ask potential participants (patients affected by stroke whose elbow is in 
flexion position) if they are interested in including the study. If they are, physician will assess 
them in terms of  following inclusion and exclusion criteria: 

 Elbow flexor spasticity 
 Grade 1 to 3 spasticity measured with MAS (5) 
 To agree to participate in the study 
 
Exclusion Criteria 
 <18 years old 
 Pregnancy 
 Botulinum toxin injection within the last three months 
 Presence of elbow contracture 
 History of operation to spastic upper extremity 
 Spasticity due to other causes other than stroke 
 Do not agree to participate in the study 
In case of voluntary participation, patients will be asked to sign written informed consent. 
Immediately after, another study physican will perform the assessments.  
 
Randomization and blinding 
This study is a non-randomized and unblinded  study. 
 
Outcome assessment and data collection 
After recording general demographic information (age, gender) and clinical patient characteristics 
(stroke type and side, disease duration, spontaneous elbow angle in upright position and 
Brunnstrom stage of motor recovery (7), participants will be assessed in terms of elbow flexor 
spasticity with MTS (6).  

Primary outcome:  Dynamic component of spasticity measured with MTS 
The MTS is a spasticity scale that evaluates the velocity-dependent muscle reaction (6). Slow 
passive stretching (V1) evaluates passive range of motion (R2). To grade the quality of muscle 
reaction, passive stretch is performed by taking into account the falling speed of the limb segment 
under gravity (V2). The quality of muscle reaction ranges from 0 to 4. Grade 0 represents no 
spasticity and grade 4 represents severe spasticity. The angle of muscle reaction (R1) [the point 
of catch in response to spasticity in case of quality of muscle reaction to be score of 2 or higher] 
is evaluated by stretching the limb segment as fast as possible (V3). The difference between the 
R2 and R1 (R2-R1) represents the dynamic component of spasticity (spasticity angle). A big 
difference suggests spasticity while the low difference suggests muscular contracture.  
Procedure 
In this study, slow controlled motion, muscle reaction to fast stretching, quality of muscle 
reaction and dynamic component of spasticity will be assessed separately in the pronation, 
neutral and supination positions of forearm unlike the classical MTS assessment. Dynamic 
component of spasticity is selected as the primary outcome measure which best represents the 
spastic component of hypertonia. The MTS measurement will be performed while the patient is 
in sitting position on an examination bed, and his/her shoulder is adducted as described elsewhere 
(8), but differently, in three different forearm positions . Patients were asked to relax as much as 
possible. First, R2 will be measured with slow controlled maneouvre at the speed of V1, and than 
muscle reaction angle and quality of muscle reaction will be measured at the speed of  V2 which 
will be extrapolated from healthy side of the patient. R2 and R1 will be measured with a standard 
goniometer (Baseline®, Fabrication Enterprises Inc, Newyork, USA) by two physician. One of 
them (A) will first position the limb, and than A will ask other one (B) to hold the positioned 
limb. Immediately after, while the B is holding the positioned limb, A will measure the elbow 

angle. To measure the R1 and R2 in supination position of forearm; axis of goniometer will be 
placed in the lateral epicondyle of humerus, stationary arm will be aligned towars the center of 
acromion process and moving arm will be aligned towards the styloid process of radius (9). To 
measure the R1 and R2 in neutral position of forearm; axis and stationary arm placement will not 
change, but moving arm will be aligned towards the long finger by positioning the wrist in a 
neutral position. To measure the R1 and R2 in pronation position of forearm; axis and stationary 
arm placement will also not change, but moving arm will be aligned towards the styloid process 
of ulna. The end position is 180 degrees of full elbow extension. Because the R1 and quality of 
muscle reaction are evaluated at the same stretching speed (V2), these two measurements will be 
performed at the same time. In case of quality of muscle reaction to be score of 0 or 1,  R1 and 
R2 will be accepted equal.  
Sample size and power 
The primary outcome of this study is to detect the differences in dynamic component of 
poststroke elbow flexor spasticity in different forearm positions. As far as we know, no such 
study has been conducted to date.  Therefore, a priori sample size calculation for this study was 
based on some arbitrary assumptions including a moderate effect size (0.25) with correlation 
among repeated measures of 0.5 and epsilon of 1 for one way repeated measure ANOVA . Based 
on these assumptions with a Tip I error rate of 5.0 and 90% power, to reject the null hypothesis of 
no difference between dynamic components of elbow flexor spasticity in three different forearm 
positions, at least 36 patients were required. Sample size calculation was performed with 
G*Power software (G*Power, version 3.1.9.2, Germany).  
Statistical analyses 
Firstly a descriptive analyses of demographic and clinical characteristics of patients will be 
performed. For the primary hypothesis, a one way repeated measure analysis of variance will be 

performed to compare differences in dynamic component of elbow flexor spasticity within three 
forearm positions. However, if the assumptions for one way repeated measure ANOVA are not 
met, Friedman’s two way analysis of varience with Bonferroni correction  will be performed. A 
level of 0.05 for statistical significance will be fixed. 
Reporting of results 
The results of this study will be presented at national and/or international meetings and will be  
pulished in journals. 
Keywords: Stroke, elbow, muscle spasticity 
Funding: No 
Ethics approval: This study was approved by the non-interventional Ethics Committee of 
Faculty of Medicine of İzmir Katip Çelebi University with approval number of 21.02.2018-84. 
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