Following a stroke, patients may present with abnormal muscle tone which will interfere with movement. It may be decreased which can be referred to as Flaccidity (Hypotonus), increased which can be referred to as Spasticity (Hypertonus) or a combination of the two. A combination of the two occurs where there is increased tone in one muscle group and decreased tone in another.
Tone may be increased temporarily by pain, discomfort, anxiety, effort and certain body positions.
Here are some simple clinical signs to differentiate low tone (Hypotonus) from high tone (Hypertonus):
- Hypotonus: Low toned muscles are floppy and sag away from their bony connections leaving the associated joints unsupported and unstable. Low toned limbs feel heavy and drop against gravity when handled if insufficient support is given. The muscle groups will feel flabby to handle and little or no resistance will be felt through the range of the movement. Great care must be taken to ensure adequate support of joints throughout their range of movement to prevent trauma injuries, particularly to the shoulder.
- Hypertonus: High toned muscles are tense and bulky, with tendons visible beneath the skin. Joints which are spanned by high tone muscles will assume a shortened position rendering the patient unable to relax. High toned muscles will resist movement and feel tight.
Stroke affects the mechanism which controls the resting levels of muscle activity. There are 2 components to hypertonia:
- Neurological
- Non neurological (musculoskeletal)
Spasticity and hypertonia are not interchangeable terms but principles for treatment are similar.
Video notes
0:07 This film shows Allan. He has a right hemiplegia. He is being assessed by Mark his physiotherapist.
As you are watching this assessment, look at the difference in tone patterns between Allan’s affected right side and his unaffected left side as he moves.
5:37 Notice what happens to Allan’s body and limbs when he is asked to raise his affected arm.
10:14 Velocity catch. Observe how the biceps muscle is affected during sudden movement.
Video transcript
Assessment of muscle tone after stroke
M. Morning Allan. I’m Mark I am your physio.
A. Hi Mark
M. How are you doing? I’m very good.
A. I’m good.
M. Nice to see you. I’m here today just to have a look at how you are moving.
A. OK
M. I’d like to get a sense of your control of your movement and we are particularly interested today in muscle tone. That is, if you like the amount of tension or relaxation in your muscles and how the stroke has affected you in that respect.
A. OK
M. Do you have any pain or injuries or anything I need to know about?
A. No
M. Any operations or what not that might affect the way you move?
A. I have had tendon err (points to right arm)
M. Transfer I think you said and a release I think?
A. I had my. My err, in there, just a release the tendon to stop the tightness.
M. So you have had some surgery on this wrist and hand. We will bear that in mind. OK.
First of all I’d just like to have a wee look at you if that’s OK. So just you relax. I’d like just to put my hands on and help you to move if that’s all right?
A. Of course.
M. If you want me to stop at any time just let me know. OK.
A. I will.
M. So just observing you at the moment you are looking good there. I can see and you have shown me that in this arm (right) there is a bit more difficulty moving than in the left. You elected to shake hands with your left hand. So this one has been affected by the stroke to some extent.
A. Yes I lost part from the stroke in the arm.
M. Ok that’s helpful. Thank you. So I’m just going to move around to your left side here. And the reason I’m moving to the left side is that I just want to feel what the muscles feel like on the side that the stroke hasn’t affected. So I’m just thinking about the amount of tension in these muscles. I’m just feeling how much tone is in them if you like and I can establish that by giving them a squeeze. So I can feel these muscles have got some activity there, but not excessive. It is quite soft and I can move the leg at the hip OK. I can lift the leg up. I can feel you following me when I move this leg. In fact you have got good control of that leg and you can move it in space. Now that tells me that on this left side in the leg you can both feel where I am putting it but you can also adjust the amount of activity in your muscles as I move it. OK. Alright.
And if I come up to your left hand here, again it feels like a very light arm. You are able to move it yourself and I can put it anywhere in space and you have got control of it. That means that you are adjusting the amount of tension in your muscles according to the position it is in space against the force of gravity. So gravity is trying to drop this arm, drop this leg through the bed. Your muscles are able to counteract that and allow this to move in space nice and smoothly and freely. That’s good. It is also telling me that in this position you are quite relaxed. OK great.
So I’d just like to come round and just have a wee comparison on this side if I may. Again, so if I come to this leg here. It is allowing me to move into medial and lateral rotation at the hip. It also feels quite low toned we would say. There’s no resistance to that movement. I am just going to come in under the heel here. Just bend your leg up a little bit. The difference here is that I’m not feeling this leg following me so much. So for example if I let this leg go. This leg is just tending to fall down to the bed. If I feel the muscles themselves, they are softer than they are on this side (left). So the muscles here are more relaxed if you like. So there’s less tension. I look as well there is more bulk in the muscle on your left than there is on the right. So the stroke has caused this muscle to get a bit smaller as well. I’ll just check the range of motion here. I feel you have got a lot of movement into lateral rotation at the hip. A bit tight into medial rotation OK. That’s quite common as the leg tends to fall out to the side especially if it’s got quite low muscle tone.
I just want to compare with the left hip. Again, just very carefully hold here. Support you here. So it’s a bit tighter at the left hip. You feel that? It’s a bit tighter.
A. Should that be slacker then?
M. It shouldn’t be anything. I think what it is showing that this right hip is very relaxed. OK, that’s fine. So if I come up to your arm now. Bearing in mind what you were able to do with the left. I’m going to lift this very carefully so we don’t cause any pain. Again, this one doesn’t quite follow in the same way. It is tending to feel quite heavy to move. Tell me if there is any discomfort associated with this.
A. I will.
M. OK so that’s good range of movement at the shoulder here. Now are you able to lift this arm in the air? OK, that’s excellent. So what we are seeing here is you are having to generate a lot of activity on the left side in order to activate the right. And we can see that we are getting quite a bit of extension activity in the right leg as well. Excellent, have a wee rest. So in this position your arm is tending to come into abduction and medial rotation as it flexes. So the elbow tends to come away from the side as opposed to up in this position.
Before I take the shoulder beyond ninety degrees I just want to check whether we have got a bit of mobility at the scapula here. So if you just relax for me a wee minute. Just let everything go. Just see what the shoulder is like here. Does that feel OK?
A. Yes.
M. When I am moving the shoulder here I am thinking of keeping the shoulder blade or the scapula and the humerus well aligned. So we are not causing any potential trauma to the gleno-humeral joint, that’s the shoulder joint. Does that feel OK?
A. Yes
M. And then as we come up into flexion. I just want to make sure that the scapula is following here so I am just feeling the spine of the scapula. That’s perfect thank you. Down to the inferior angle and just make sure the scapula comes up as well. Any pain there?
A. No
M. Excellent. And relax again. Have a wee look at your hand. Have a wee stretch. Reach up towards the ceiling. There you go. So we can get up to ninety degrees combined shoulder flexion with protraction and rotation of the scapula. Then we can just bring the arm gently back. So maintaining the alignment of the shoulder girdle as we bring it up into flexion. Just have a look at your hand again there. Perfect. A wee bit of restricted range of motion there but not too bad.
As we look at the muscles we can see here that there is increased flexor activity going on. I am just checking here at pectoralis major and minor. There is a little bit of increased activity there but you see most of the increased activity is in biceps and in brachioradialis here at the elbow. We can see there is a resistance to passive stretch. So these flexors are active when it comes to relaxing into extension we can see there is a resistance to that. You can see the muscle activity here which is different to this side here (left) where there is more relaxation. Now this is typical of an upper motor neurone spasticity where we have got a “clasped knife” phenomenon where it feels tighter in the middle range of the motion then as we go towards the end of range that releases. “Clasped knife “phenomenon is what it is called. There is no rigidity or tremor associated with this. This is a classical picture of spasticity. We can confirm this just by palpating the muscles and we can feel that there is much more activity in these flexors than really there ought to be in this position. Because it should be able to relax down just on to the bed. If I come, and bearing in mind. You OK there?
A. Yes
M. Bearing in mind the surgery as well. I’ll be careful here.
A. There a lot of pain that I get in this arm.
M. OK. How is the sensation on this side when I am touching you?
A. A dull, dull feel.
M. You can feel it is duller than this side?
A. Yes
M. Is there any pain or burning or tingling or pins and needles?
A. No.
M. Again we can see we have got a restriction in extension at the wrist here. I can just get beyond neutral. I don’t want to overcome this because we have obviously got some surgical involvement there. We also lack a bit of supination.
A. Totally.
M. And again that’s the sort of position it would have been in and we have released in to this. Again we can feel that there’s a little bit of a tension to extending the fingers. But again, in relation to the surgery, I’m not going to push this too far. But obviously we would be looking to get the hand into a more extended position.
If I. Because this is what’s called “velocity dependent”. You find that if I stretch slowly then the muscle releases quite easily. If I stretch quickly we can see that the muscle “catches”. So we have a “catch” if you like in mid-range here. And as we keep extending it, so the muscle generates more activity. So in terms of controlling this muscle tone or releasing it, slow is best. So a nice slow stretch. We can lay our hand on the muscle as well which actually causes the muscle to relax locally in order to then extend. Then we can extend the wrist and fingers distally as well. So we can block the wrist with the lateral border of the hand. Steady the thumb, steady the fingers and just gradually put extension on the wrist. But I wouldn’t. Had you not had the surgery we could have worked this a little bit further. The alternative is to flex at the elbow. Put the extension on the wrist and fingers and then extend the elbow. There’s a couple of ways to do it. So whenever people are working with you Allan, it’s probably a good idea to discuss as a team the way we manage this.
A. Aha. OK
M. So the long wrist flexors in the forearm. The flexors in the fingers. The elbow, the shoulder are all the areas which can tighten up we want to try and control. Let’s just relax this arm down on to the bed again. That’s good. OK.
Page last reviewed: 04 May 2020