Pain: remember me? Significance of psychosocial factors in affecting motor skill training

  

I have discussed the idea that cortical reorganisation occurs among many pain states. The greater the chronicity of pain the greater the neuroplastic changes. Exercise; particular motor skill training in particular can assist in the reversal of such maladaptations.

Towards the end of my previous post I made a comment regarding the pyschosocial factors having have a comparable effect on learning like that of pain.in that under the influence of pain, novel skill acquisition is reduced.

Physiotherapy is moving to a much more psychosocial focused paradigm. I would like to end my blogging experience by touching on the role of pyschosocial factors within neuroplasticity.

It is well evidenced that the experience of pain is shaped by a whole host of cognitive and behavioural factors and that some factors such as fear, anxiety, beliefs regarding pain, avoidance of movement and mood are shown to be prognostic factors in the development of chronic pain (Linton & Shaw 2011).

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Image 1. A modern view of pain perception from a psychological perspective according to Linton (2005)

Out with the old in with the new

The body; a large widespread network of neurones that consists of loops between  the thalamus and cortex and cortex and the limbic system is an entire network, whose spatial distribution and synaptic links are determined initally by genetics but later sculptured by sensory inputs is termed a ‘neuromatrix’. The ongoing cycle of processing and synthesis of nerve impulses through the neuromatrix impart a characteristic pattern known as the neurosignature. The neuromatrix is genetically progammed to perform the specific function of producing the signature pattern. It is distributed throughout many areas of the brain and generates patterns and processes information that travels through it and ultimately produces a pattern reflecting the whole body.

Appreciatively this view is largely different to the previous notion that the pain experience is proportional to peripheral injury or pathology. Previous pain theories; pattern theory and the pain gate theory have paved the way for this neuromatrix concept. 

In persistent pain states there is an associated with overactivity of the pain neuromatrix increased activity is present in a number of cortical areas within the brain; insula, anterior cingulate cortex, prefrontal cortex (Seifort and Maihofner 2009). The amygdala is one key brain area involved in the pain neuromatrix often referred to as the  memory centre of fear. It plays a primary role in the processing of memory, decision making and emotional reactions. negative emotions and pain related memories. Evidence through neuroimaging suggests that the amygdala plays a key part in facilitating the development of chronic pain and the increase in sensitivity of the central nervous system pain pathways ( Simons et al 2012).

What does this mean in practice? The significance of this in practice is the recognition of the brain and in particular the amygdala’s role in pain memory. In particular memories of painful movement. The amygdala’s collaboration with the hippocampus and anterior cingulate cortex can explain the display of antalgic postures, gait and altered motor control in chronic pain patients (Nijs et al 2015). This understanding signifies how a patient who has had a previous painful experience that associate’s pain as being harmful can display maladaptive movement without the presence of nociceptive input.

Getting the best out of  exercise: changing pain memories

Cognition targeted exercise in patients with chronic pain can be effective in changing pain memories in patients with chronic musculoskeletal pain and centeral sensitisation (Nijis et al 2014). Cognition targeted exercise is an approach that focuses on addressing patients perceptions about exercise through thorough questioning and discussion before during and after exercise. It is an approach that is not time contingent like driving plasticity with icreased number of repetition but  symptom contingent (Nijis 2015).

I hope my blog has been purposeful in that when  you are next treating a patient with persistent pain you may question, what affect you are hoping to have and where. This may drive how you treat them and consequently facilitate your outcomes.

Thankyou for taking the time to read.

References

Linton S and Shaw W. Impacet of Psychosocial Factors in the experience of Pain. Physical Therapy 2011;91:700-711

Nijis J, Meeus M, Cagnie B, Roussel NA, Dolphens M, Van Oosterwijck J. A modern  neuroscience approach to chronic spinal pain: combining pain neuroscience education with cognition-targeted motor control training. Phys Ther 2014;94(5):730-8

Nijis J, Girbes E, Lundberg M, Malfliet A and Sterling M. Exercise therapy for chronic musculoskeletal pain: Innovation by altering pain memories. Manual Therapy 2015;20:216-22

Seifart F and Maihofner C. Central mechanisms of experimental and chronic neuropathic pain: findings from neuropathic pain: findings from functional imaging studies. Cell Mol Life Sci: CMLS 2009;66:375-90

Simons LE, MoultonEA, Linnman C, Carpino E, Beccera L, Borsook D. The human amygdala and pain:evidence from neuroimaging. Hum Brain Mapp 2012;25:2199

Motor Learning in Musculoskeletal practice

   
As mentioned in my previous blog a common example of neural adaptation is learning.
In novel motor skill acquisition cortical neuroplastic changes are frequently associated with an advantageous change such as an increase in motor performance. Conversely, in persistent pain neuroplastic changes are often linked with unfavourable behaviour such as a decrease in motor performance.
As altered motor performance is thought to be a factor for the maintenance of pain, motor rehabilitation approaches that aim to re-establish normal motor strategies are an important factor to consider in the treatment of musculoskeletal pain disorders.

 

Image 1. New theory of Motor Adaptation to pain. (Hodges and Tucker 2011)

Learning from each other.  Collaboration between specialities

Much of the evidence that underpins the basis of neuroplasticity and the potential for re establishing normal motor strategies in musculoskeletal patients is based on evidence in patients with neurological disorders.

Recognising neuroplasticity as a component in patients with musculoskeletal dysfunction may lead to a greater understanding of neural mechanisms that influence musculoskeletal dysfunction. By addressing maladaptive neural organisation through the recognition of neuroplasticity the effectiveness of treatments that target motor behaviour such as movement quality and muscular strength could be improved.(Snodgrass et al 2014)
In stroke the best evidence based inventions that demonstrate a positive effect on neuroplasticity and motor learning are intensive repetitive practice and task specific training (Richards et al 2008, Van vliet 1993 and French et al 2007).
Although there is new found evidence in the role of neuroplasticity within musculoskeletal practice musculoskeletal Physiotherapists continue to be guided by exercise protocols justified through clinical trials (Bystrom et al 2013)

Shaping our practice

Prior to now I had not really considered the relation between pain and altered motor performance in the context of cortical reorganisation. I certainly never contemplated the principles of inducing plasticity when treating my patients.

Numerous studies have identified through the use of functional magnetic resonance imaging (fMRI) that during a painful experience there is an increase in activity in specific areas of the brain. These include the primary and secondary somatosensory cortex, insular, anterior cingulate cortex, prefrontal cornices and thalamus. (Peyron et al 2000, Henry 2000, Apkarian et al 2005)

Novel motor skill training in healthy individuals compared to passive assistance or repetitions of general exercise has been shown to improve task performance and provide an increase in representation of the trained muscle in the motor cortex (Karni et al 1995, Pascual-Leone et al 1995, Svensson et al 2003, Hlustik et al 2004).

 

Image 2. Primary motor cortex homunculous (Wikipedia)

Svensson et al 2003 showed during one week of novel tongue task training an increase in motor representation of the tongue muscle occurred and that there was an increase in cortical excitability of the tongue primary motor cortex. Increased cortical excitability was also demonstrated for the hand primary motor cortex following novel motor training in a study by Koeneke et al 2006.

Furthermore both studies suggest that neuroplastic changes in the motor cortex can occur over a short period. Improvements in motor performance and rapid changes in cortical excitability of the tongue primary motor cortex occurred immediately after just 15 minutes of novel tongue task training.

Based on the evidence that novel motor skill training is associated with rapid changes in cortical excitability and cortical reorganisation this training approach is considered relevant in the treatment of patients with musculoskeletal pain and movement dysfunction.          Image result for bOUDREAU 2010 MOTOR SKILL TRAINING

Figure 3. Cortical maps of the face primary motor cortex. Expansion of the tongue muscle representation following novel task training. (Svensson et al 2003)

Training the activation of a delayed or inhibited muscle through the use of repeated isolated voluntary contraction is an effective clinical approach commonly used in the management of musculoskeletal pain disorders.
Tsao et al, 2010 observed that maladaptive changes in the motor cortex reverted towards that of a healthy individual with task specific exercises in persons with low back pain.
Transcranial Magnetic Stimulation (TMS) revealed that deep abdominal muscle training consisting of voluntary activation of the Transverse Abdominals (TrA) independently from other trunk muscles induced an anterior and medial shift in motor cortical representation of the trained muscle towards that of healthy asymptomatic individuals in persons with low back pain compared to that of walking as a control intervention.
Subjects were positioned in crook lying and were instructed to activate their TrA. Electromyographic activity recorded the contraction once patients could activate with little use from their abdominals, contractions were held for 10 seconds whilst continuing to breath . 3 sets of 10 were performed twice a day.
Those in the control group were required to walk at their own pace for 10 minutes twice a day for 2 weeks.
Although the basis of using this approach is based on the principle of novel motor skill training, further key components in motor skill strategies have emerged that could advance  rehabilitation outcomes.

Skill or Strength

Motor skill training requires great skill and a high level of attention and precision in comparison to the mere contraction of a group of muscles such as strength training. A study by Remple et al 2001, identified that motor skill training coupled with strength training did not promote any greater cortical neuroplastic changes in the motor cortex compared to motor skill training alone. These findings are in keeping with the study by Tsao et al 2010, that showed an increase in reorganisation of the motor cortex following skilled training compared to that of just walking. The observation of improvements in the amplitude and speed of activation of the deep cervical flexor muscles through isolated training of these muscles as opposed to strengthening exercise in patients with neck pain further support the importance of motor skill training over strength training (Jull et al 2009).

Role of pain

Many studies that have examined the effects of acute experimental pain have found that pain can alter the excitability of the motor cortex.
Compared to the rapid changes that are associated with motor skill acquisition, the changes in cortical excitability that occur in association with experimental pain or persistent pain do not necessarily correspond to the muscle groups represented in the motor cortex. For example induced pain at the finger in a study by Koflet et al 1998, revealed an induced increase in excitability of the hand primary motor cortex but at the same time a decrease in excitability of the upper arm muscles. These pain related changes in excitability of the motor cortex may suggest why patients move differently when in pain. The findings would help to explain why maladaptive movements occur but not necessarily at the location of where we would expect.

Incremental gains in task performance have been shown not to occur when pain is present this is thought to be due to the effect that pain has on suppressing the rapid increase in cortical excitability (Boudreau et al 2007).
The belief that pain hinders novel skill acquisition is in keeping with other factors that are well known to hinder learning unfortunately such are commonly found in chronic pain patients. These include increased stress, reduced cognition, reduced quality of sleep and attention deficit.

What is the purpose?

A goal orientated sequential finger tapping task was associated with a significant increase in representation of the trained muscle in the motor cortex compared to a protocol that required mental rehearsal of the finger tapping task and even more so than the random performing of the finger tapping task.
Altering the complexity of the task was noted to further enhance cortical neuroplastic changes. A complex finger tapping task compared to a simple finger tapping task showed additional areas of cortical activation under fMRI (Pascual-Leone et al 1995). These findings suggest that purposful meaningful tasks that require cognitive effort contribute significantly to the extent of cortical neuroplastic changes.

How many repetitions? Quality versus Quantity

Hundreds of repetitions of movement in varying contexts are necessary for inducing cortical change (van Vliet et al 2012). However, it is important to remember that this is not always achievable without the presence of pain. As mentioned earlier pain does not support novel motor skill acquisition. There has been studies that suggest the use of imagery when pain prevents a patient from performing the task. Boudreau et al 2010, suggested that if rapid changes in cortical excitability are apparent following short training sessions (approx 60 within-session task repetitions over the course doc 10-15 minutes) such a high number of repetitions isn’t actually required and therefore the number of task repetitions should be based upon all of the principles discussed through the course of this post in order to improve the performance of a motor task.

References

Apkarian AV, Bushnell MC, Treede RD and Zubieta JK. Human brain mechanisms of pain perception and regulation in health and disease. Eur J Pain 2005;9:463-84 doi:10.1016/j.ejpain.2004.11.001

Boudreau S, Farina D and Falla D. The role of motor learning and neuroplasticity in designing rehabilitation approaches for musculoskeletal pain disorders. Manual Therapy 2010;15:410-414

Bystrom M, Rasmussen-Barr R and Grooten W. Motor control exercises reduces pain and disability in chronic and recurrent low back pain a matter analysis. Spin 2013; 38(6):E350-8

Figure 2. Cortical homonculous available at: http://en.wikipedia.org/wiki/Cortical_homunculus. last accessed 23/11/15

French B, Thomas LH, Leathley MJ, Sutton CJ, McAdam J and Forster A et al. Repetitive task training for improving functional ability after stroke. Cochrane database Syst Rev 2007 (4):CD006073

Hlustik P, Solodkin A, Noll DC and Small SL. Cortical plasticity during three-week motor skill learning. Journal of Clinical Neurophysiology 2004;21(3):180-91

Henry P, Creac’h C, Caille JM, and Allard M. Functional magnetic resonance imaging analysis of pain related brain activity after acute mechanical stimulation. American Journal of neuroradiology 2000;21:1402-1406

Hodges P and Tucker K. Moving differently in pain: A new theory to explain the adaptation to pain. Pain 2011;152:90-98

Jull GA, Falla D, Vicenzino B and Hodges PW. The effect of therapeutic exercise on activation of the deep cervical flexor muscles in people with chronic neck pain. Manual Therapy 2009;14(6):696-701

Koeneke S, Lutz K, Herwig U, Ziemann U and Jancke L. Extensive training of elementary finger tapping movements changes the pattern of motor cortex excitability. Experimental Brain Research 2006;174(2):199-209

Karni A, Meyer G, Jezzard P, Adams MM, Turner R and Ungerleider LG. Functional MRI evidence for adult motor cortex plasticity during motor skill learning. Nature 1995;377(6545):155-8

Kofler M, Glocker FX, Leis AA, Seifert C, Wissel J, Kronenberg MF and Fuhr P. Modulation of upper extremity motoneurone excitability following noxious finge tip stimulation in man: a study with transcranial magnetic stimulation. Neurosci Lett 1998;246:97-100

Pascual-Leone A, Nguyet D, Cohen LG, Brasil-Neto JP, Cammarota A, and Hallett M. Modulation of muscle responses evoked by transcranial magnetic stimulation during the acquisition of new fine motor skills. Journal of Neurophysiology 1995;74(3):1037-45

Peyron R, Laurent B and Garcia-Larrea L. Functional imaging brain responses to pain: a review and meta analysis. Neurophysiol Clin 2000;30:263-88

Remple MS, Bruneau RM, Vandenberg PM, Goertzen C and Kleim JA. Sensitivity of cortical movement representations to motor experience: evidence that skill learning but not strength training induces cortical reorganization. Behavioral Brain Research 2001;123(2):133-41

Richards LG, Stewert KC, Woodbury ML, Sensec C and Cauraugh  JH. Movement dependent stroke recovery: a systematic review and meta-analysis of TMS and fMRI evidence. Neurophy 2008;46:3-11

Snodgrass S Heneghan N, Tsao H, Stanwell P, Rivett D  and Van Vliet P. Recognising neuroplasticity in musculoskeletal rehabilitation: a basis for greater collaboration between musculoskeletal and neurological physiotherapists. Manual Therapy 2014; 19:614-617

Svenson P, Romaniello A, Arendt-Nielson L and Sessle BJ. Plasticity in corticomotor control of the human tongue musculature induced by tongue-task training. Experimental Brain Research 2003;152(1):42-51

Tsao H, Galae M and Hodges P. Driving plasticity in the motor cortex in the current low back pain European Journal of pain 2010

Van Vliet PM, Matyas T and Carey LM. Training principles to enhance learning-based rehabilitation and neuroplasticity. In: Carey LM, editor. Stroke Rehabilitation: insights from neurosciences and imaging. Oxford: University Press: 2012. pp. 115-26. ch. 9