PNF in hemiplegic gait

[gcoe]

PNF is a collection of techniques for facilitation a muscle contraction, strengthening and increasing flexibility. From what I understand Herman Kabat used it this way while Maggie Knott and Dorothy Voss popularised these ideas into a package that is how it is used today. For example Knott and Voss created the stylised spiro-diagonal patterns. It takes considerable skill to use the popularised method. And I don’t think you can learn it on your own from a book.

PNF is now 60 years old, so it has been around for a long time. Like the ideas of Berta Bobath, Margaret Rood, and Signe Brunnstrom recovery of the nervous system was thought to be achieved by the facilitation or suppression of certain reflexes. In the case of PNF techniques these are:

• The application of quick stretch (monosynaptic stretch reflex)
• Resistance (monosynaptic stretch reflex)
• Maximal contraction of antagonists (with subsequent facilitation of the antagonist and inhibition of agnonists)
• Proximal to distal facilitation (spinal cord irradiation)
• Kabat emphasised the use of mass patterns that had a primitive functional basis (eg using the flexor withdrawal reflex to facilitate flexion, positive supporting reaction to facilitate extension of the lower limb, feeding patterns to facilitate flexion in the upper limb and so on). Knott and Voss took this one step further an developed their spiro-diagonal dogma based on the way muscles tend to lie in oblique directions often with a rotational component.

These methods are therefore often described as belonging to the reflex-hierarchical model of motor control. This model arose from the foundations neurophysiology the beginning of the 20th century. While some of this was good science for the time, the model is a highly impoverished model of neuroscience; full over oversimplifications and conjecture about the relative importance of these phenomena.

There are some really big problems with these techniques which has a lot to do with the outdate nature of the reflex hierarchical model of motor control.

Limited understanding of how the nervous system, movement and motor learning works.
The problem with the using techniques from this model is that our understanding of motor control and motor learning has become so much more developed. Our understanding of biomechanics, motor learning theory and research, motor control, psychology of motivation, neuroscience particularly neuroplasticity has taken us a long way from these very simplistic notions of how the nervous system work and how we learn and relearn movement. For example the various uses of PNF provide a very poor examples of motor learning.

Evidence Base
There is very little in the way of adequate quality of research that supports the use of PNF. In contrast many other approaches such as the task-based approaches have now accumulated considerable evidence for their effectiveness.

Would I use it for gait training? No. If I want to get a muscle to contract in relation to a component of walking FES has a very good track record in terms of efficacy and if you have a hand control or a foot switch you can utilise in the practice of walking. If you want to strengthen a muscle group then used a science based strengthening protocol (eg ACSM protocols for nornal and special populations using Progressive resistance training) There are also a number of other task-based approaches that appear to have promise: component practice, body weight support treadmill training,

For further reading on These issues have a read of:

Carr, J. H., & Shepherd, R. (2000). Movement science : foundations for physical therapy in rehabilitation. Rockville, Md: Pro-Ed Incorporated.
Shumway-Cook, A., & Woollacott, M. H. (2007). Motor Control: Translating research into Clinical Practice (3 ed.). Philadelphia PA: Lippincott Williams & Watkins.

[estherderu]

A lot of years ago(25 or so)

I was part of a practicle clinical study into the differences in effect of using NDT/Bobath or PNF with hemiplegic patients.
Nothing was ever published but I can tell you that:
1. Patients all preferred PNF because it made them work harder, the "therapists language" was easier to understand. By this I mean, the licht "stearing touch" or the percievable "push against".
2. patients percieved themselves as becoming stronger
3. they also liked the fact that they were working hard and not being "steared/pushed" around.

I often think we tend to forget the patient themselves in our pursuit of quality treatment.

Esther

[gcoe]

Hi Esther

This sounds like an interesting study. If your recall of the findings is right and the findings are sound then it provides some valuable insights into patients experiences

I agree that research can downplay patients experiences. We don’t ask our patients enough about their views on therapy. Incorporation of patient participation in planning, carrying out and reviewing research as consumers and the inclusion of well conducted qualitative research can make clinical research more thorough.

2. patients percieved themselves as becoming stronger

It doesn’t surprise me that patients perceive themselves as becoming stronger. Maybe they were becoming stronger! The Bobath approach doesn’t really address strengthening – in fact traditionally Bobath therapists are quite averse to strengthening and believe bad things come from such activity. In contrast PNF is primarily used in hemiplegia to strengthen. After much research and debate it appears that weakness is may well be the most important impairment in hemispheric stroke. So that is one up for techniques that employ strengthening. However does that mean PNF is the most effective form of strengthening? There is an absence of evidence here. In contrast there is a wealth of support for progressive resistance training and some evidence for FES and also for biofeedback (Ada, Dorsch, & Canning, 2006).

3. they also liked the fact that they were working hard and not being "steared/pushed" around.

This seems a really important psychological issue. Working hard may feel empowering and in my experience PNF oriented therapists tended to be less concerned with controlling functional movement but letting the patient practice this following performing PNF. In contrast the Bobath experience is of having one’s movement controlled in which only the therapist knows how to facilitate this. This shifts the locus of control off the patient and on to the all powerful therapist. Patients are not really permitted to experience practicing their own movement and learning to improve performance through the usual experiences such as self initiated repetition and learning from ones mistakes. This has always struck me as one of the more unfortunate aspects of the Bobath approach, and is contrary to good motor learning theory.

In the end we need to be aware of what are the most important outcomes for patients. This can be debated but a common desirable considered now is being able to walk at sufficient speed, endurance, and dexterity to safely and confidently walk in the community. Does PNF have any supporting evidence for this or any other walking outcome? I could only find one rather old study of rather dubious quality (Dickstein, Hocherman et al. 1986). The outcomes of that study showed no real superiority or inferiority of PNF to traditional approach and Bobath.

A number of more recent approaches appear to help (Dickstein 2008). However I think on the whole we need to be mindful that our effect on improving functional outcomes in stroke is quite modest. Finding treatments that are effective enough to improve participation in the community is proving to be difficult. Personally I don’t think the long term direction is going to be to clinging to past techniques based on simplistic models of movement science and lacking evidence of effectiveness.


Ada, L., Dorsch, S., & Canning, C. G. (2006). Strengthening interventions increase strength and improve activity after stroke: a systematic review. Aust J Physiother, 52(4), 241-248.
Dickstein, R. (2008). Review article: Rehabilitation of gait speed after stroke: A critical review of intervention approaches. Neurorehabilitation and Neural Repair, 22(6), 649-660.
Dickstein, R., Hocherman, S., Pillar, T., & Shaham, R. (1986). Stroke Rehabilitation: Three Exercise Therapy Approaches (Vol. 66, pp. 1233-1238).

[neurospast]

Quote:
These methods are therefore often described as belonging to the reflex-hierarchical model of motor control. This model arose from the foundations neurophysiology the beginning of the 20th century. While some of this was good science for the time, the model is a highly impoverished model of neuroscience; full over oversimplifications and conjecture about the relative importance of these phenomena.

There are some really big problems with these techniques which has a lot to do with the outdate nature of the reflex hierarchical model of motor control.

Limited understanding of how the nervous system, movement and motor learning works.
The problem with the using techniques from this model is that our understanding of motor control and motor learning has become so much more developed. Our understanding of biomechanics, motor learning theory and research, motor control, psychology of motivation, neuroscience particularly neuroplasticity has taken us a long way from these very simplistic notions of how the nervous system work and how we learn and relearn movement. For example the various uses of PNF provide a very poor examples of motor learning.
end quote.

I have taken (hopefully not out of context) a quote from gcoe. What surprises me, maybe I misunderstand gcoe, that simply because the theory behind the system is outdated, PNF seems to be outdated. How come? Wouldn't it be better to see if a system works and if it works to proclaim (in case PNF does work) that the theory behind it is outdated but that PNF does work. I am not sure but I feel this sort of assault could be on every principle within physiotherapy treatment. e.g. Bobath, spinal manipulation and so on. In stead of looking if there is some practical use for these treatment systems should we be blinded by the theory behind it which seems to be outdated? I am wondering...
I assume you, gcoe have done PNF courses and found them completely a waste of time and have come therefor to your statement. So it is not entirely based on theory (which will most likely be outdated next year).

[gcoe]

Thank you for your response.

You seem quite scornful of scientific theory. In my opinion physiotherapy is a health science. Sound theories don’t arise out of a vacuum but out of a need to better explain the results of experimental research. Theories don’t change with the wind. Occasionally they may start with a sudden insight, sweeping away what went before but more often theories evolve slowly. Changes don’t happen overnight. And theories do need to be updated as new research comes to light. I think this is a good thing. Far from making such theories unreliable keeping up to date with such theory can provide you with a much firmer foundation on which to base your clinical reasoning.

quote: "Wouldn't it be better to see if a system works and if it works to proclaim (in case PNF does work) that the theory behind it is outdated but that PNF does work."

In these days of evidence-based practice an intervention to be considered effective must meet two criteria:

1. To start with it must have a sound biomedical basis. If there isn’t a sound basis that is rooted in such things as movement science then we are not even off to square one. It is quite possible for techniques that have no understood basis or a poor basis to be effective. But the likelihood that it will turn out to be effective is greatly decreased. Rather then shooting in the wind and hoping we might hit the target by some random chance, why not choose interventions that are more likely to hit the target based on good science. Having a sound basis for an intervention improves our ability to reason through the use of the intervention and how better apply the technique.

2. It must be backed by sound research that provides evidence for its effectiveness. Now days we expect that interventions have a good track record with replicated randomised clinical trials, and hopefully we can someone has pooled these trials into a systematic review of the intervention. Anecdotal evidence provided by a physio is not an adequate standard for evidence that a technique works.

My point here is that PNF fails on both these counts. Relying on a biomedical concept that dates back to the beginning of the 20th century and that has been hugely surpassed by an enormous amount of science is not a sound justification for evaluating a technique. PNF has some evidence for stretching in sports and orthopaedic settings but that is not why we are using it in neuro. We are interested in strengthening for improved function. There is also little evidence for employing the technique. I found two trials that examined PNF, both of poor quality (3-4/10 PEDro scale) One study supported its use and one study showed it was no better than other methods. This is not good evidence for PNF. 60 years after its appearance; I think we could have a bit more evidence than two weakly designed studies:

PEDro - Selected Search Results

Quote: “I am not sure but I feel this sort of assault could be on every principle within physiotherapy treatment. e.g. Bobath, spinal manipulation and so on”

This is exactly right! I am not singling out PNF. For example Bobath comes in for exactly the same limitations as PNF. – except in the case of Bobath there is more evidence but the evidence discourages adopting it. As health science professionals we should be questioning what we do and we should be coming up with better interventions as our knowledge of what works gets better.

A few years ago there was not that much evidence for neurological physiotherapy. That has now changed and it is getting better.

Strengthening techniques such as FES, biofeedback, progressive resistance training, component practice in walking, to a limited extent body weight support treadmill training, distributed practice and summated feedback on gait are just to name some techniques for improving gait.

Likewise our scientific understanding of what we are doing has greatly improved. So rather than getting stuck on techniques with little scientific merit why not make use of what is out there.

[neurospast]

I don't think you get my point at all. I am just saying that an outdated theory does not allow you to say that a treatment is rubbish. To my opinion that is foolish. To find 2 researches on PEDRO which are obvious below parr does not even make the point (it does just tell us that research is needed which is upto scratch!).
Furthermore to assume that the way research is done at the moment is the state of art is pure arrogance and does not allow us to reflect and to improve.
As Esterderu points out patient involvement was greater in the PNF group, which will effect the emotional state of mind e.g increase amount of endorfines which will effect the aptients well being and thus promote recovery e.g. effect on the cerebellum.
Scornful of scientific science? No just sceptic which is actualy a scientific way of outlook.
Until several years ago it was assumed recovery after a stroke was lets say 90% first 3 months after a stroke. We know now that actually nerve cells can recover, can be renewed (we still have no clue how I suppose) but unfortunately our healthcare and thus our science is still in the middle age thinking we put an effort in 1st 3 months. So actually the research might outdated...I suppose

[estherderu]

dear both,

I would very much like to take part of this discussion but I am on holidays at the moment, I just couldn't resist reacting.
Will get back to you both on this subject in a few weeks time.

One thing is for sure....
Most physiotherapists had their PNF education during their PT training. How many have done the official PNF courses I do not know. All of the therapists I have met, in various countries, had never been to one of the official PNF courses and were just doing what they had been taught at the time. And to make matters worse, NON of all these people had ever even heard of the trunk patterns.

I do know that very few people are members of the IPNFA and that you can only become a member after having followed the standard training.
I will see if I can get one of the other IPNFA members(instructors) to react as well.

kind regards

Esther