The Movement Project - Part 1: Is Altered Movement Really the Underlying Mechanism for Mechanical Pain?

 If you rehabilitate movement you should know this

Do not take for granted that everyone can learn or benefit from cognitively altering or controlling movement

Background

There are several schools of thought which aim to cognitively alter and / or control movement patterns for the treatment of mechanical pain. The underlying premise linking this rehab concept to musculoskeletal symptoms is based on some simple concepts:

• The way that the central nervous system (CSN) coordinates movement can influence tissue loading
• The CNS has numerous motor control options when producing a movement
• End range movements are needed and required for normal function
• Frequent use of end range movements can increase tissue loading
• Some people habitually use their end range movements
• Subjects with low back pain (LBP) move their hips more than their lumbar spine during trunk flexion and extension, therefore loading tissues

These points provide the biological plausibility for the intervention but it does raise a more important question:

Why does the CNS chose to move the spine in a manner that will potentially increase tissue loading and harm the spine?

Therefore prescribing exercises to cognitively alter or control movement of the spine is analogous to empiric therapy. Clearly the underlying mechanism(s) are required and treatment should specifically target them. No other school of thought specifically targets the functional mechanism as to why the CNS chooses a potentially harmful movement pattern.

This question facilitated the Movement Project with the goals to:

• Identify and understand the functional mechanisms of altered movement. Since there may be genetic influences, the goal was to consider modifiable factors.
• Develop intervention strategies that specifically target the functional mechanisms
• Test these interventions clinically
• Predict who will respond to this type of intervention

We are happy to say that the Movement Project is completed. The projects that were completed to get here include:

• Narrative review and systematic review of mechanisms of altered trunk movement patterns
• Development and testing (laboratory and clinical) of an underlying hypothesis
• Development of a preliminary clinical prediction rule as to who will respond to this therapy
• Clinical trial on cognitively altering movement patterns
• Systematic review of interventions that cognitively alter movement patterns

This project brought about The Learning Project because we learned from the Movement Project that one of the functional mechanisms was related to learning difficulties and the neurodevelopmental process.

We know how to rule in and rule out who will respond to this therapy. Approximately 20% of people cannot learn these exercises. We have interventions for those who do not learn and targeted interventions for the functional mechanisms of altered movement. 

Sean GT Gibbons BSc (Hons) PT, MSc Ergonomics, PhD (c), MCPA

Is Idiopathic Toe Walking Caused by Retained Primitive Reflexes?

Toe walking, also referred to as "tip toe behavior", entails walking on the toes or forefoot, with a lack of heel strike upon initiation of the stance phase of gait. It is believed to occur normally during development of tandem heel-toe gait, but should resolve by 3–7 years of age. Toe walking may occur in three modalities: class 1(in standing, walking and running); class 2 (in walking and running) and class 3 (only during running). The prevalence of toe walking at age 5.5 is 2% in normally developing children, and up to 41% in children with neuropsychiatric diagnosis or developmental delays, with a slight male predominance. The prevalence may be up to one-third in autism spectrum disorders (Valagussa et al 2015). The biomechanical effects of toe walking overlaps with those described in another article on functional hallus limitus.

The exact etiology of ITW remains unknown. Although the majority of toe walkers are otherwise healthy children, it is important to assess each case with a high index of suspicion as toe walking can be due to a structural problem such as a contracted tendon, compensation for a short limb, or a manifestation of autism spectrum disorders, cerebral palsy, muscular dystrophies, or other neurologic or neuromuscular conditions. Toe walking has been associated with speech/language delays, abnormalities in executive functions, social skills, learning, and memory, with differences in motor control, sensory processing, and vibration perception thresholds when compared with adolescents with normal gait. At the cellular level there is an increased concentration of type 1 muscle fibers among toe walkers. Ten to 88% of idiopathic toe walkers have a family history of toe walking with an autosomal dominant inheritance with incomplete expression observed in some families.

Causes of Toe Walking

·         Cerebral palsy

·         Congenital muscular dystrophy

·         Tethered cord syndrome

·         Diastematomyelia

·         Autism

·         Schizophrenia

·         Global developmental delay

·         Charcot-Marie-Tooth disease

·         Spina bifida

·         Transient dystonic reaction

·         Venous malformation of the posterior calf muscle

·         Ankylosing spondylitis

·         Congenital or posttraumatic limb-length discrepancy

Treatments for toe walking include physiotherapy, orthotics, serial casting, chemical denervation, and surgical lengthening of the gastroc– soleus–achilles complex. Recent systematic reviews show good evidence for the use of casting and surgery, with surgical interventions showing the most promising long term results.

So Is Idiopathic Toe Walking Caused by Retained Primitive Reflexes?

Primitive reflexes are a type of neurological soft sign and are associated with many of the conditions noted above to be potential causes of toe walking. There are a family of foot primitive reflexes which have a motor response of plantar flexion. As well, plantar flexion is a motor response of other trunk extension reflexes. The foot tendon guard, plantar grasp and heel grasp are the foot reflexes which most closely reproduce the toe walking pattern.

Although evidence based treatments are noted above, there are always non responders and the treatments can be very inconvenient and / or invasive.

All toe walkers have these reflexes. It is unknown for sure if the reflexes are the cause of toe walking or a secondary manifestation. In any case, the reflexes are easily treated in most infants and children. In some children, the extensor reflexes will need to be treated as well as sensory motor deficits.

Primitive reflex inhibition can provide a conservative option for the treatment of toe walking in children. Parents or caregivers can easily be taught the techniques with monitoring and progression guided by the therapist. 

 Sean GT Gibbons BSc (Hons) PT, MSc Ergonomics, PhD (c), MCPA

References

Babb A, Carlson WO 2008 Idiopathic toe-walking. S D Med. 61(2):53, 55-7.

Dietz F, Khunsree S 2012 Idiopathic toe walking: to treat or not to treat, that is the question. Iowa Orthop J.32:184-8.

Durrant B, Chockalingam N 2009 Functional Hallux Limitus: A Review. Journal of the American Podiatric Medical Association. May/June, Vol 99, No 3. 236-243

Engström P, Tedroff K 2012 The prevalence and course of idiopathic toe-walking in 5-year-old children. Pediatrics. 130(2):279-84. doi: 10.1542/peds.2012-0225. Epub 2012 Jul 23.

Eiff MP, Steiner E, Judkins DZ, Winkler-Prins V 2006 Clinical inquiries. What is the appropriate evaluation and treatment of children who are "toe walkers"? J Fam Pract. 55(5):447, 450.

Oetgen ME, Peden S 2012 Idiopathic toe walking. J Am Acad Orthop Surg. 20(5):292-300. doi: 10.5435/JAAOS-20-05-292.

Ruzbarsky JJ, Scher D, Dodwell E 2016 Toe walking: causes, epidemiology, assessment, and treatment. Curr Opin Pediatr. 28(1):40-6. doi: 10.1097/MOP.0000000000000302.

Sivaramakrishnan S, Seal A 2015 Fifteen-minute consultation: A child with toe walking. Arch Dis Child Educ Pract Ed. 100(5):238-41. doi: 10.1136/archdischild-2014-307852. Epub 2015 Apr 8.

Valagussa G, V. Balatti, L. Trentin, V. Terruzzi and E. Grossi 2015 The Hardness of Standing Support Surfaces Influences Tip-Toe Behavior of Autistic Children: Evidence from a Pilot Study. International society for Autism Research. Salt Lake City, UT, USA May 13-16

Valagussa G, V. Balatti, L. Trentin, S. Melli, M. Norsi and E. Grossi, 2015 Toe Walking and Autism: Cross-Sectional Study on Presentation Patterns and Correlation with Autism Severity. International society for Autism Research. Salt Lake City, UT, USA May 13-16

Why Does Replicating a Primitive Reflex Inhibit the Reflex?

The replication of primitive reflexes is growing in evidence. It has been used effectively in several intervention and laboratory studies in children and adults. At first glance, this is in conflict to various therapies that use normal movement such as the Bobath or NDT approach.

First it is important to understand the difference between the "replication" and the "reproduction" of the primitive reflex (PR).

Replication of the Primitive Reflex

(1) Where appropriate, the sensory stimulus is slowly and passively replicated.

(2) The movement pattern of the PR is cognitively and actively replicated. There is no automatic response of the reflex

Reproduction of the Primitive Reflex

During either the stimulation of the sensory reflex or during the replication of the movement pattern, there is an unconscious reproduction of the primitive reflex. This is non therapeutic and can be harmful to the motor control pattern. It happens more often with reflexes that have a tactile sensory stimulus, during the stimulation of the tactile stimulus (e.g. Babinski, Foot Tendon Guard, Sucking Reflexes). Note: in neurological patients, the reproduction of the PR is frequently seen during functional movements or while using normal movement or postural responses to inhibit the reflex.

These observations likely have contributed to the misconceptions of PR Replication to inhibit the reflexes. It is critical to the therapeutic effect that the PR is not reproduced replicated while it is cognitively being replicated.

The Neurodevelopmental Process

There is a belief that the neurodevelopmental process is a sequential development:

Primitive Reflexes » Sensory Motor » Postural Reflexes » Goal Orientated Movement

Although this is a nice way to explain the process in textbooks, development doesn't occur as simple as this. Development uses each of these processes to "feed off" of each other.  In general terms it could be said that in early development the former may be more dominant (primitive reflexes and sensory motor) and in later development the latter may be more dominant (postural reflexes and goal orientated movement).

For example, an infant is prone and hears a sound. This auditory stimulus  (sensory) facilitates an extensor response and the head and trunk move into extension (primitive reflex). When the head is up (and during) oculomotor is used (sensory) and the vestibular system and kinesthetic system (sensory) is stimulated. The infant may then decide to move (goal orientated movement).  If it is a roll (postural reflex, but can be primitive depending on the time frame), there is lower limb, upper limb and neck "coordination", the vestibular system and kinesthetic systems are stimulated (sensory) and the tactility system is stimulated (sensory).

In gross terms, as the neurodevelopmental process and primitive reflexes are going through their normal developmental timeframe, higher cognitive centers (frontal lobe) are facilitated. The appreciation of this neurodevelopmental principle has helped us understand and develop a hypothesis of why the replication of PR helps inhibit the PR. 

We have now observed three cases in infants which have helped develop and support our hypothesis that it is the cognitive and active replication of the reflex which inhibits the PR.This in turn facilitates specific higher centers which then inhibit the reflex.

The observations were:

1.    In the same setting the infant's reflexes were checked and the infant had a grasp reflex

2.    The infant made a conscious decision to reach for a toy and grasped it fully and then brought it back to their body

3.    The infant's primitive reflex was absent immediately following the activity of making a cognitive decision to reach for the object and achieve the goal of grasping it and bringing it back to their body.

In infants or in adults it may be possible that passively replicating the PR can also have a clinical benefit. This may be through the mirror neuron system. If our hypothesis is correct, we need to take advantage of the cognitive aspect of the process during our clinical application of PR inhibition.

Although we need further clarification and understanding of the central mechanisms, these cases and hypothesis provide a plausible hypothesis to pursue. 

Sean GT Gibbons BSc (Hons) PT, MSc Ergonomics, PhD (c), MCPA

References

Edwards S, Sarwark JF 2005 Infant and Child Motor Development. Clinical Orthopaedics and Related Research. Number 434: 33–39

Gibbons SGT 2009 Neurological soft signs are present more often and to a greater extent in adults with chronic low back pain with cognitive learning deficits. Manual Therapy. 14 (S1): S20

Gibbons SGT 2009 Primitive reflex inhibition and sensory motor training improves cognitive learning function and symptoms in chronic disabling low back pain: A case series. Manual Therapy. 14 (S1): S24

Gibbons SGT 2011 Neurocognitive and sensorimotor deficits represent an important sub-group for whiplash associated disorders. Fifth International Whiplash Trauma Congress. Aug 24-28; Lund, Sweden. J Rehabil Med 2011; Suppl 50: 23

Gilfoyle EM Grady AP Moore JC 1990 Children Adapt. A Theory of Sensoirmotor-Sensory Development. 2nd Ed. SLACK Incorporated, Thorofare

Goddard S 2005 Reflexes, Learning and Behavior. Fern Ridge Press. Eugene, Oregon. USA

Jordan-Black JA 2005 The effects of the Primary Movement programme on the academic performance of children attending ordinary primary school. Journal of Research in Special Educational Needs. 5 (3): 101–111

McPhillips M, et al 2000 Effects of replicating primary-reflex movements on specific reading difficulties in children: a randomized, double-blind, controlled trial. The Lancet 355: 537-340

Parfrey K, Gibbons SGT, Drinkwater EJ, Behm DG 2014 Head and limb position influence superficial EMG of abdominals during an abdominal hollowing exercise. BMC Musculoskeletal Disorders. http://www.biomedcentral.com/1471-2474/15/52