Basic Bobath Course

Part IBergen March 1st-12th 2004

POSTURAL CONTROL

THE BOBATH CONCEPTMARY E LYNCH-ELLERINGTON.

POSTURAL CONTROL.

The ability to control our body’s position against and within the forces of gravity is fundamental to everything we do.

Almost every movement that an individual makes is made up of both postural components (which stabilise the body ) and prime mover components (which relate to a particular movement goal)

(Massion & Wooollacott 1996.)

AIMS

To define and discuss normal postural control.

To develop links between the development of postural control and the systems control model.

To analyse aspects of postural control in a no of postural alignments for the development of efficiency.

RELEVANCE

Postural Control emerges from a complex interaction of sensory and musculoskeletal systems, integrated and modified within the CNS and in response to changing environmental conditions.

The recovery of postural control post stroke is considered to be a critical component of the motor behaviour for achieving independence in ADL.

WHAT IS THE TASK OF POSTURAL CONTROL ?

To be able to control the body’s position in space for the purposes of both orientation and stability.

POSTURAL ORIENTATION.

This involves The ability to maintain the appropriate

alignment between body segments The appropriate relationship between the body

and the environment. Requires establishing a vertical orientation to

counteract the forces of gravity. Creates a reference frame for perception and

action with respect to the external world.

POSTURAL STABILITY

This involves

Maintaining the body’s centre of mass within boundaries of space, referred to as stability limits.

Stability limits are boundaries of an area of space in which the body can maintain it’s position without changing it’s base of support.

STABILITY LIMITS.

Stability limits are not fixed but may change according to

the taskthe individualthe environment.

Postural Action can be viewed as a motor skill that emerges from the interaction between the individual, the task and the environment.

POSTURAL STABILITY.

DIFFERENT TASKS WILL PUSH ASPECTS OF STABILITY TO BEYOND THE STABILITY LIMITS AND NECESSITATE A CHANGE IN THE BASE OF SUPPORT.

SOME TASKS SUCH AS DIVING TO SAVE A FOOTBALL WILL PLACE GREATER EMPHASIS ON ORIENTATION TO THE BALL THAN ON STABILITY AND A CONTROLLED FALL IS THEN ATTEMPTED.

POSTURAL CONTROL

Postural Control may be less automatic than previously thought. It has been suggested that maintaining postural stability does require some degree of attention…..research has similarly demonstrated that attentional demands increase as balance requirements of a task increase

(Hunter & Hoffman 2001) Cognitive demands associated with balance

may contribute to the incidence of falling among older adults.

(Brown et al 1999)

SYSTEMS CONTROL OF POSTURE .

DESCENDING

ASCENDING

PERIPHERAL

“Posture is safeguarded by multiple inputs and outputs. It reflects the care that evolution has bestowed on the capability to adjust the body to the direction of gravity, and parts of the body in relation to each other.” (Brooks 1986)

PLAN.

INTERNAL REPRESENTATION ROLE OF SENSORY INPUTS POSTURAL CONTROL STRATEGIES RECOVERY OF BALANCE CLINICAL TESTS OF BALANCE IMPROVING EFFICIENCY OF

POSTURAL CONTROL AND BALANCE.

INTERNAL REPRESENTATION

It is thought that an internal representation of body posture exists within the CNS.

This is often referred to as the “ Postural Body Schema”.

Body Schema incorporates body geometry, kinetics, orientation with respect to gravity.

BODY SCHEMA

DEFINITION

“ A POSTURAL MODEL ONE HAS OF ONESELF, HAVING TO DO WITH HOW ONE PERCEIVES THE POSITION OF THE BODY AND THE RELATIONSHIP OF BODY PARTS…………

BODY SCHEMA

………..IT IS BELIEVED TO BE THE BASIS OF ALL MOTIONS, FOR ONE NEEDS TO KNOW THE PARTS OF THE BODY AND THEIR RELATIONSHIP IN ORDER TO KNOW WHAT, WHERE, AND HOW TO MOVE ONESELF.

(Zoltan et al 1991)

BODY SCHEMA-GEOMETRY

Body geometry-is thought to depend upon proprioceptive 1a afferents from all parts of the body.

“Recent findings suggest that trunk or hip inputs may be more important in triggering human balance corrections and that proprioceptive input from the lower legs mainly helps with the final shaping and intermuscular coordination of postural and gait movements” (Allum 1998)

BODY SCHEMA-KINETICS

Body Kinetics-has two aspects of control

1. The nervous system’s evaluation of the support conditions

2. The calculation of the inertia of different body segments, used for providing an accurate estimation of the centre of gravity position.

LITERATURE REVIEW

When a subject supports their weight through their upper limbs the postural reactions involve mainly the arm extensor muscles in place of the leg muscles. (Massion & Woollacott 1996)

Cutaneous foot sole sensors and foot muscle proprioceptors monitor amplitude and direction of contact forces and are important in upright stance control.

(Kavounoudias et al 1998)

BODY SCHEMA-ORIENTATION

A top down orientation of the body is given by the labyrinthine sensors which allow detection of the head position in space, relative to gravity.

Visual information detects movement and monitors head and body displacement with respect to the external world.

Evidence exists for the presence of graviceptors.

LITERATURE REVIEW

“These graviceptors would monitor the force vector exerted at each joint to oppose gravity and this information would contribute to an internal representation of the vertical axis.A putative candidate for the monitoring of this sensory information is the Golgi tendon organ which measures the number of active motor units at a given time in each muscle used in postural control”

( Massion & Woollacott 1996 )

LITERATURE REVIEW

“ There is preliminary evidence to suggest that somatic gravity receptors, originating from viscera within the trunk exist in monkeys and in humans “

(Di Fabio & Emasithi 1997 )

Recent research has argued for a separate pathway in humans for sensing body orientation in relation to gravity.

( Karnath et al 2000 )

MODERN LITERATURE

‘ Internal models are considered a general neural process for resolving sensory ambiguities, synthesising information from disparate sensory modalities, and combining efferent and afferent information ’

(Perennou et al 2000)

POSTURAL CONTROL STRATEGIES.

REACTIVE ( Compensatory )

PREDICTIVE ( Anticipatory )

COMBINATION OF BOTH.

REACTIVE STRATEGIES

ANKLE STRATEGY HIP STRATEGY STEPPING REACTIONS GRASP WITH HAND PROTECTIVE EXTENSION OF THE

UPPER EXTREMITIES.

PREDICTIVE STRATEGIES

ANTICIPATORY POSTURAL ADJUSTMENTS DURING VOLUNTARY MOVEMENT

RIGHTING AND EQUILIBRIUM REACTIONS

POSTURAL ADJUSTMENTS

LIMBMOVEMENT

CENTRAL COMMAND

POSTURALDISTURBANCE

POSTURALADJUSTMENT

EQUILIBRIUM & RIGHTINGREACTIONS

Equilibrium reactions consist of minute postural adjustments which allow maintenance of a desired posture.

When greater perturbation necessitates visible activity is seen. The response of the body is to extend on the weight bearing side and flex on the other.

Rotation may be seen within the body axis. ( Mayston 2001)

EQUILIBRIUM & RIGHTINGREACTIONS

In the mature adult Righting Reactions cannot be separated from Equilibrium Reactions.

Righting & Equilibrium Reactions allow the loss and regaining of midline through appropriate head and trunk activity within the equilibrium response.

In efficient subjects these reactions are observed in all sequences of movement e.g. sitting to lying, walking etc.

RECOVERY OF BALANCE

Postural control strategies can become more efficient and effective with training and practice ( Horak et al 1997. )

Somatosensory cues are a powerful orientation reference for improved control of upright stance ( Jeka 1997. )

RECOVERY OF BALANCE

KEY QUESTIONS.

Trained separately or as part of the taskor goal ?

Practiced simultaneously ?

RETICULOSPINAL SYSTEM

MEDIAL

LATERAL

CORE STABILITY

THE CO-ACTIVATION OF THE ABDOMINALS AND MULTIFIDUS TO STABILISE THE TRUNK AND HEAD DURING SELF INITIATED OR FACILITATED LIMB ACTIVITIES

VESTIBULOSPINAL SYSTEM

Vestibular

Somatosensory

Visual

Midline Position and motion of the

head Control of posture and tone

Automatic postural responses

Cutaneous-amplitude and direction of contact forces important for locomotion.

Control stance Signals position and movt of

head with respect to surrounding objects

VESTIBULOSPINAL SYSTEM

CONTRIBUTES TO HEAD ON BODY STABILISATION.

EXCITES THE ANTIGRAVITY MUSCULATURE – POSTURE SPECIFIC.

AUGMENTS EXTENSION IN LOCOMOTION.

MEASUREMENT

CLINICAL SCALES The Berg Balance Scale The Functional Reach Test Timed Tasks (e.g. single leg stance) The Postural Assessment Scale for Stroke

(PASS)

PHYSIOLOGICAL ASSESSMENT Posturography Force platforms.

SUMMARY

“Control of posture and movemnt requires initiation and planning at the highest level, control and updating from the middle level, and execution and regulation of the task at the lowest level.

However it must be stressed that interaction between these levels is constant and ongoing, providing information in both directions. “

(Edwards 1996)

PRACTICAL

POSTURAL ORIENTATION CONTROL OF STABILITY LIMITS ALIGNMENT & STRENGTH

REFERENCES

Allum J, Bloem B, Carpenter M, Verschuuren J, & Honegger F (2002) “ Triggering of balance corrections and compensatory strategies in a patient with total leg proprioceptive loss “ Experimental Brain Research, Vol. 142,No 1, p 91-107.

Di Fabio R & Emisithi A (1997) “ Aging and the mechanisms underlying head and postural control during voluntary motion” Physical Therapy, Vol. 77, No 5, p458-475.

Edwards S (1996) “ Neurological Physiotherapy: A Problem Solving Approach, Churchill Livingstone, London.

Horak F, Henry S, & Shumway-Cook A (1997) “ Postural Perturbations: New Insights for Treatment of Balance Disorders” Physical Therapy, Vol.77, No.5,p 517.

Hunter M and Hoffmann M (2001) “Postural Control, Visual and Cognitive manipulations” Gait and Posture, Vol.13, No. 1, p 41-48.

Jeka J (1997) “ Light touch contact as a balance aid” Physical Therapy, Vol.77, No. 5, p 476-487.

Karnath H, Ferber S & Dichgans J (2001) “ The neural representation of postural control in humans “ Proceedings of the National Academy of Sciences of the United States of America, Vol.97 No.25, p13931-132936.

Kavounoudias A, Roll R & Roll J (1998) “ The plantar sole is a dynamometric map for human balance control” Neuro Report, Vol. 9, No. 14, p 3247-3252.

Mayston M (2001) “Problem solving in Neurological Physiotherapy: setting the scene in Edwards S (Ed) Neurological Physiotherapy: A Problem solving approach. Churchill Livingstone London.

Perennoiu A, Leblond C, Amblard B, Micallef J, Rouget E, Pelissier J (2000) “The polymodal sensory cortex is crucial for controlling lateral stability “ Evidence from Stroke. Brain Research Bulletin April

Shumway-Cook A & Woollacott M (1995) Motor controlIsbn 0683077570.Zoltan,Siev & Freishtat (1991) The Adult stroke Patient A

Manual for Evaluation and Treatment of Perceptual and Cognitive Dysfunction. 2nd Edition N.Jersey Slack INC.