i Mh 201 Lecture 8 Handouts

7/30/2019 i Mh 201 Lecture 8 Handouts

1/14

10/30/20

IMH 201

History of Motor andSensory Development

Rosemary White OTR/LSeptember - December 2008

WEEK VIII

Development of Posturalon ro

References for this Lecture

Lectures on Neurodevelopmantal Therapy and SensoryIntegration presented by Rosemary White, 1980 to present.

Motor Control Translating Research into Clinica l Practic e

Cha pte r 8; Develop me nt of Postural Cont rol; p.187 - 209

The Components of Normal Movement During the First Year

of Life and Abnormal Movement, Lois Bly 1983 Monograph,Neuro-Developmental Treatment Association; p. 1 - 40


2/14

10/30/20

Postural Control& Development

Research on early development has shown that

simultaneous development of the postural, locomotor,and manipulative system is essential to theemergence and refinement of skills in all areas.

Amiel Tison and Grenier, 1980 note that when aninfant is provided with stability in the head and neckmovements seen in more mature infants emerge.

Gesell, 1946 described movement development overthe first few years Proximal to distal control

Spiraling Hierachy

Characterized by alternating advancement and regression inthe ability to perform skills

Magnus - Reflexes & Righting

Static Reactions

Stiffen limbs for support of body weight againstgravity

Se mental Static Reactions

Involve more than one body segment (flexorwithdrawl and crossed extension.)

General Static Reactions (Attitudinal reflexes)

Involve change in position of body in response tochanges in head position.

Righting Reactions

Allow animal to assume or resume orientation ofbody with respect to environment.

Attitudinal Reflexes/Reactions(Static)

Assymetrical Tonic Neck Reflex - ATNR Rotation of the head -> Extension on the facial side, flexion

on the occipital side.

- Extension of the neck -> extension in the UE, and flexion in

the LE; Flexion of the neck -> flexion in the UE andextension in the LE

Tonic Labyrinthine Reflex (in a prone position) - TLR Flexion of the neck -> flexion throughout the extremities;

Extension of the neck -> extension throughout the body.

Elicited by stimulation to Proprioceptors in the neck, vestibular

To a lesser degree visual and auditory


3/14

10/30/20

Phasic Reflexes/Reactions

Moro Reflex -

When the child is displaced backwards in space there is an

increase in extensor tone in the extremities followed by a return toflexions (vestibular.)

Startle Reflex -

When there is a sudden sound the infant will have an increase ini i ill i iextensor tone in the extremities and then a return to flexion(auditory.)

Galant Reflex -

When there is tactile stimulation down the side of the spinal cordthe infant will have contractions of the muscles on that side of thetrunk leading to lateral flexion and then return to neutral (tactile.)

Stepping Reflex -

When an infant is held upright with his or her feet placed on asurface, he or she will lift their legs as if they are marching orstepping (touch pressure to the foot).

Righting Reactions

Orientation of head within space, and orientation of the headto the body and ground.

Neck Righting - Rotation of the head and neck and the body followswith no segmentation.

Labyrinthine - Orientation of the head within space to bring the noseinto a vertical ositon, mouth horizontal relative to ravit . Sensorsystem that influences this is the vestibular.

Body on Head - Body responds and re-aligns to movement of the head.Sensory system that influence this are somatosensory in neck, but alsovisual and auditory can influence.

Head on Body - Head and neck respond and re-align to movementinitiated by the body. Sensory system that influences this is primarily thesomatosensory (proprioception and tactile.)

Body on Body - Body parts respond to one another and with regard toorientation to the ground. Sensory system that influences this is the

primarily the somatosensory. Optical Righting - Orientation of the neck and body within space using

visual input.

NECK RIGHTING

Rotate head body moves in total

piece

Newborn in prone

None

Proprioceptive

Tactile

Vestibular

LABYRINTHINE

Adjust to right head in space (nosevertical/mouth horizontal)

0-4 months in prone

Neck -Vertical

- Lateral

- Rotational

Vestibular

Utricle

Saccule

BODY ON HEAD

Body adjusts on head movement

Neck -Vertical

- Lateral

Proprioceptive

Tactile

Automatic Postural MechanismsRighting Reactions - http://www.therapyedu.com/pedi/chapter9.htm

RIGHTING REACTIONS SEGMENTATIONSENSORY STIMULUS

(Lift head in prone body adapts)

HEAD ON BODY

Head adjusts on body movement(Lift bottom to change diaper headadjusts flexing)

3 months in prone

- Rotational Vestibular

S.C.C

Utricle and Saccule.

Cerebellum

BODY ON BODY

One part of body moves and rest ofbody adjusts to that initiatingmovement

4-5 months prone

Trunk -Vertical

- Lateral

- Rotational

Proprioceptive and Tactile

Vestibular

S.C.C.

Utricle and Saccule

Cerebellum

OPTICAL

Using visual cues to influencepostural responses in body

Newborn

All the above are foundations forOptical Righting

Visual

Optical System

? Vestibular


4/14

10/30/20

EQUILIBRIUM REACTIONS

Reactions that serve to maintain or regain balance once the

center of gravity has been displaced.

Develop in a plane, or during a movement pattern, after all theri htin react ions havedevelo ed asan e uil ibrium react ioni i i l , ili i iis made up of all of the righting reactions working together inthe presence of normal muscle tone.

There are two types of equilibrium reactions:

i. When you move on a stable surface- walking, climbing stairs or

really any movement pattern in which you maintain control.

ii. When you are stable, but the surface upon which you aresupported moves- in a bus, or car, or boat.

Balance and Protective Reactions

Reflex-hierarchical theory - Balance emerges inassociation with a sequentially organized series ofequilibrium reactions, of which there are three types -

Tilting Reactions Control the center of gravity when tilted (emerge in prone,

then sitting, then in stance.)

Parachute or Protective Reactions Protect body from injury during a fall (emerges forward, then

sideways, then backwards.)

Staggering Reactions (sideways stepping) Occur in response to instability in a lateral direction.

(Wollacott & Shumway Cook, 2007)

EQUILIBRIUM REACTIONS

STATIC

Support Surface moves (carry, car,Rx Ball)

Align center gravity overbase ofsupport

Proximal/Distal kinesiological

aspect of control

All levels as all righting reactionsworking together

Proprioceptive

Tactile

Vestibular

Visual

Initiating sensory stimulus is fromexternal source

Equilibrium Reaction Segmentation Sensory System

Begin 6 months prone continues todevelop in all positions to 6-7 years

DYNAMIC

Support surface stable but bodymoves (roll, crawl, walk, climb, inRx facilitate thru transitions)

Bring base of support undercenter of gravity

Distal/proximal kinesiologicalaspects of control

Begin 6 mths prone continues todevelop in all positions to 6-7 years

All levels as all righting reactionsworking together

Proprioceptive

Tactile

Vestibular

Visual

Initiating sensory stimulus is frominternal source


5/14

10/30/20

Adequate Sensory Integration

Postural Adaptation

Midline Stability Equilibrium

(Static Balance) (Dynamic Balance)

Vertical Righting Rotational Righting

Labyrinthine Body on BodyHead on Body Optical

Bod onHead

Phasic Reactions Tonic Reactions

(Movement Reactions) (Holding Reactions)

Moro ATNR

Rooting TLR

Muscle Development

Visual

Tactile

Proprioceptive

Vestibular

IMH 201 Week VIIIPart 2

Development ofPostural Control

* On pa ges in the Lecture for Week VII Video

Full Sec tion is for your rea ding s and for referenc e forFull Video with Slides.

*Theories of DevelopingPostural Control

Classic Theories (reflex hierarchy substrate) Posture and movement control is dependent on

appearance and subsequent integration of

reflexes. More recent theories (systems, ecological, &

dynamic actions theories) Postural control emerges from a complex

interaction of musculoskeletal and neural systems -postural control system with organization ofelements determined by task and environment withreflexes being only one of the many influences onposture and movement.


6/14

10/30/20

*Role of Reflexes

Controversial

Some researchers believe that reflexes arethe substrates for motor control. e s e as s or eye an co-or na on

while others disagree.

Righting reactions are the basis for rolling ininfants.

Are these postural patterns a reflection ofneurological maturation - hence as movementemerges they reflect the integration of sensory,affective, emotion maturation?

*Systems Theory

Interaction of the child with the environment Changes in the musculoskeletal system.

Balance of neuromuscular structures.

Development of sensory systems.

Integration of sensory systems.

Internal representations -> mapping of perceptions to action.Considered essential for comparisons, interpret self motionand calibrate motor actions.

Adaptive and anticipatory mechanisms -> child modifies theway they sense and move.

Thus the path from sensation to motor actionsproceeds via an internal representationstructure or body schema (Gurfinkel & Levik,1978, Hirschfield, 1992)

*Emerging Head ControlMotor Co-ordination

Prechtl, Harborne, Hedberg, Hirschfield & Frossberg,Woolocott and others have designed research

paradigms to understand motor development -

Lack of head control in infants was the result of lack ofstrength as well as lack of organized muscle activity.

Muscle contractions in the neck and trunk were assessed inresponse to postural displacement in infants as young as 1month through 10 months. Results indicated the emergenceof directions specific postural responses in the neck flexorsbegins as young as one month but responses occur only athird of the time, and by 5 months half to time. In contrastneck extension was more consistent at one month occurring70% of the time and remaining that way through five months

It was pure science.


7/14

10/30/20

*Emerging Head ControlSensory Contributions

Research to assess capacities based onresponse to sensory input.

Infants as young as 3 days old responded posturally to isolatedvisual -motor action (back and forth of a moving dot - evenwithout affect!)

This indicates that the subneural networks that contribute tovisual proprioceptive control of posture is present at birth.

Learning is not required for the emergence of optic flowsensitivity, although experience and self-producedmovement may be important for visual/posturalcoupling. (Jouen et al 2000)

*Emerging Head ControlRelating Reflex to Systems Theory

Reflex/hierachical theory suggest that visual co-ordinationappears at approximately 2 months as optical righting matures.

Body righting and labyrinthine emerge between birth and 2months.

Landau emerges between 4 and 6 months when all rightingii

Systems theory suggests that certain basic visual/posturalmapping is present at birth and with movement the infantdevelops refined rules for mapping visual information for action.

Sensory motor mapping occurring in first 2 months.

Mapping between visual and vestibular system for posturalaction present between 2.5 and 5 months.

Both theories are consistent suggesting that mapping of

individual senses to action may precede the mapping ofmultiple senses of action reflecting the internal neuralrepresentation necessary for co-ordination.

Emergence of Independent Sitting(6 to 8 months of age)

To sit independently the infant must learn tomaster control of both spontaneousbackground sway of the head and trunk and

. This requires co-ordination of sensory/motor

information relating two body segments (head andtrunk) together for postural control.

Research indicates that there may be both innatecomponents of control in the newborn as well asemergent aspects of control resulting from theinfant interacting dynamically with the environment.


8/14

10/30/20

Emergence of Independent SittingMotor Co-ordination & Balance

Three Stages reflect the dynamic process in which the infantgradually learns to control the degrees of freedom involved inhead/trunk control.

Infant able to hold up head and trunk when positioned insitting but not independently.

i il i n an si s momen arily - secon s or props wi arms(a time if decreased freedom.)

Sits independently but not yet crawl .

Infants exhibit the precursors for balance in sitting prior toindependent sitting.

Reactions are stronger in response to backward movementsthan forwards.

Reactions are present in the first month, less frequentbetween 3 and 4 months, then reappear with greaterfrequency and refinement at 5 months and as the childlearns to sit independently.

Emergence of Independent SittingSensory Contributions

Studies have looked at the role of the visual sense inemergence of sitting. Infants who had little experience sitting independently had

complete loss of balance in response to visual stimulation ofi i i i i ii i i i i i

less influenced and their response declined. This suggeststhat early sitters use vision to provide stability but withexperience they rely more on somatosensory input.(Butterworth et al, 1977 & 1983)

Studies with continuous oscillation of visual cues led tocontinuous postural adaptation in the pelvis. This suggeststhat in the process of developing independent sitting infantslearn to scale or map visual sensory information to their

postural activity. (Bertenthal et al, 1997)

Emergence of Independent SittingSensory Considerations

Studies have looked at the role of the other senses inemergence of sitting.

Balance was challenged in sitting, with and without vision,indicating that there was no difference in muscle activationpatterns. This indicates that somatosensory and vestibular

systems are capable of eliciting postural actions in isolationi i i i l i i li i i i l i i . l ,

Head orientation was systematically varied while seatedinfants balance was disturbed -> Finding that coordinatedmuscle activity in the trunk did not change regardless ofhead position. This indicates that in sitting motor responsesare largely controlled by somatosensory input at the hips, notvestibular or visual. (Hirschfeld and Forssberg, 1994)

Infants who were not yet sitting independently were trainedover a three month period with toy presentation to the side orsemibackwards to the limit of their stability. Trained infantsbalance responses were more efficient when compared tonon trained infants. (Hadders-Algra, 1996)


9/14

10/30/20

Emergence of Independent SittingRelating Reflex to Systems Theory

Reflex-hierachical theory highlights orientation of the body

emerging at around 6 months with maturation of neck-on-bodyand body-on-body righting and relates it to the dynamicemergence of rolling. Magnus described their actions to affectbody orientation of the head and neck (neck-on-body) andsupporting surface (body-on-body)

Systems theory research indicates the childs ability to orient thehead and trunk with respect to the support surface is present ina crude form shortly after birth, it then goes through furthermaturation from 4 through 9 or 10 months which coincides withemergence and maturation of independent sitting.

Both theories have agreement concerning emergence oftrunk control but different underlying explanations

Transition to StanceMotor Co-ordination

Requires maintenance of balance on a smaller base of supportand co-ordination of leg and thigh segments with those of thetrunk and head.

Strength - Infants have strength in LE to produce force greater thantheir body weight at 6 months. This suggests that the infant has theabilit to su ort wei ht a ainst ravit well before inde endentlstanding, hence strength is not a major factor.

Development of Muscle Synergies - Studies infants 2 months to 18months revealed postural response synergies in response to threats tobalance in fall backwards disturbance.

2-6 months infants (no pull to stand behavior) no co-ordinatedmuscle response organization.

7-9 months infants (emerging pull to stand behavior) haddirectionally appropriate response in ankles. As pull to standincreased thigh segment emerged (distal to proximal sequence)

9-11 months trunk muscles were activated - a complete synergywith gradual addition of muscles to synergy with experience anddevelopment.

Transition to Independent StanceSensory Contributions

Vision maps to muscles controlling stance postureappear to be present by 5-6 months of age, beforesomatosensory mapping, and long before the infant is

standing, suggesting that the infant has to reassemblet e synerg es w en somatosensory nputs aremapped for stance postural control.

5 month olds swayed in response to roommovement, this increased during the pull to standphase and peaked with independent walkers, thendropped with experiences walkers. This suggeststhat somatosensory system develops synergiesseparately in association with somatosensoryinput.


10/14

10/30/20

Transition to Independent StanceAdaptive Capability

Postural adaptation to changing support surface was assessed in

infants 13 - 14 months. They were assessed on varying surfacesthat had elements of instability (resistive, slick and narrowsurfaces). They had better balance on the resistive and no abilityon the narrow surface which requires hip adaptation. Thissuggests that adaptation in the hips is not mastered in the firstyear of walking. (Stoffregen, 1997)

When the size of the balance threat was increased passivelynew walkers with 3-6 months of walking had hip determinedresponses (Wollacott, 1998; Roncesvalles, 2003)

When adaptation was actively assessed in new walkers (10-17mths); hopper (2-3yrs); gallopers (4-6yrs); skippers (7-10yrs) -it was not until 7-10yrs that children began to show consistentactive control of strategy with high levels of abdominal muscleactivity.

Transition to Independent StanceRelating Reflex to Systems Theory

The divergence of focus of the theories makecomparison difficult.

Reflex/hierachical theory distinguishes the rightingreactions underlying orientation from the tilting andpostural fixation reactions essential to the emergenceof balance. Thus suggesting different neural mechanisms are involved.

Systems theory suggests that the time course foremerging stability is different in each of the sensorysystems. Visual inputs relating the bodys position in space map to

muscular action controlling the bodys position during stance

emerges earlier than the somatosensory, and the vestibularis not yet known.

Refinement of StanceMusculoskeletal System

The center of gravity in a child is higherthan that of an adult due to the fact that

the head is heavier. This fact and theact t at a c s s orter -> c rensway at a faster rate that adults makingstatic balance more difficult. This persists until 7 years of age

(Lebiedowsha & Syczewska, 2000; Zeller,1964)


11/14

10/30/20

Refinement of Stance

Motor Coordination

Younger children make large fast correction as they adapt over

their base of support. By 8-9 years they show shorter excursionsand more accurate control .(Riach & Starkes, 1994)

Variance in sway amplitude becomes systematically lower withage and improved balance.

Contribution of vision to balance during stance. Children of 4years swayed more with eyes open; 9-12 year o lds reach adultlevels with eyes open, and 12-15 year olds reach adult levelswith eyes closed. Sway velocity also decreases with age.(Taguchi & Tada, 1988)

3 year olds have restricted degrees of freedom over base ofsupport in quiet stance balance; 5 year olds have more controlover and adaptability over their base of support (center ofpressure.) (Newell, 1997)

Refinement of StanceCompensatory Posture

Compensatory postural responses in 15 month olds are morevariable and slower than adults, with bigger sway amplitudes andmore oscillations. (Fossberg and Nashner, 1982)

Children 18 months to 3 years produce well organized muscleresponse when balance is threatened , but they are larger anddelay of response and duration are longer.(Shumway Cook andWollacott, 1985)

Children 4 to 6 year olds have a regression of postural response

organization.

The body is growing and previous motor programs are no longerhighly effective -> period of transition with marked instability andvariability and then a new plateau of stability. Kugler et al, 1982)

Developmental changes in the nervous system.

Children 7 to 10 years old have responses similar toadults.

Refinement of StanceSensory Adaptation

Postural control is characterized by the ability to adapthow we use sensory information about the positionand movement of the body in space to changing task

and environmental conditions. Visual inputs reporting the bodys position in space

appear to be mapped to muscular actions earlier thaninputs from other sensory systems.

The invariant use of visual inputs from postural controlcan sometimes mask the capability of other senses toactivate postural reactions. At times when vision isoccluded postural actions activated by other sensoryinputs can be better organized.


12/14

10/30/20

Refinement of Stance

Sensory Adaptation

Predominance of visual control of balance gives way tosomatosensory control of balance by age 3 but is not adult like

until after 7. 4-6 year olds had more sway than older children when balance

was challenged even when they all sensory input available.

When vision was occluded the had reater swa but did noti i l ifall.

When somatosensory was reduced they had reduced stabilityand half the group lost balance.

When the children had to maintain balance using primarilyvestibular input all but one lost their balance.

Thus, children under 7 are unable to maintain efficient balancewhen both somatosensory and visual cues are removed.

In addition when one or more sensory cue is inaccuratelyreported (hence there is conflict) children under the age of 7have reduces ability to posturally adapt.

Refinement of StanceAnticipatory Control

Skilled movement has both postural (stabilizing framework) andvoluntary components (primary movement.)

Studies show that prior to an action there is an anticipatorypreparation in muscles.

When reaching in sitting (3-6 months) it was found that asi l i ii l i i ,

amount of postural activity decreased due to posturalstablity.

When 10 to 17 month olds opened a cabinet draw instanding it was found that anticipatory muscle activityoccurred in the leg prior to action in the arm.

10 to 11 month anticipatory activity was present but notconsistent.

13 months had consistent anticipatory posture.

Experienced walkers showed more rapid anticipatory posture inhalf the children but if there was resistance they did not haveadaptational abilities until 15 months. (Witherington, 2002)

*Cognitive Systems inDevelopment

Postural control requires attentional resources withadditional resources required with increasing posturaltask complexity.

While performing a postural or a cognitive task orboth a childs performance will deteriorate ifattentional capacities are exceeded. Studies show that postural demands of younger

children tax their attentional resources more thanolder children during dual tasking (maintainingbalance while doing a visual memory task. (Reilly,unpublished)


13/14

10/30/20

*Development of Postural Control

Changes in motor components of postural control

involve Body morphology - body is shorter and head isheavier and influences balance up until 6 years. After6 bod balance is more that of an adult. .

Refinement of muscular response synergies when

balance is threatened

Decrease in onset latency,

Improvement in timing and amplitude of muscleresponse,

Decrease in variability of muscle response

-> Decrease in sway velocity and reduction ofoscillatory sway.

*Development of Postural Control

Refinement in the sensory aspects of posturalcontrol include -

A shift from predominance of visual control of balanceto a somatosensory control of balance by age 3.

The ability to adapt senses for postural controlappropriately is reduced, in children under 7, whenone or more of these senses (visual, somatosensory,vestibular) is inaccurately reporting body orientationinformation.

The ability to perform both postural and cognitive

tasks in dual task situation is reduced in childrenunder 7.

*Sensory, Affective, Emotional Contribution

Was there something missing in thisresearch when we compare the results of

natural environment ?

What are the contributors to infantsamazing capacities?


14/14

10/30/20

Reflection for the Week

Review Video of movement.

Consider postural control and the integrationof movement relating to the body - reflex to

.

Do you see one theory or the otherinfluencing your observations. What are thethe major influencing your observations.

Remember function, neurobiology, integrationand emotion as you consider this reflection.

i Mh 201 Lecture 8 Handouts

Documents

Transcript of i Mh 201 Lecture 8 Handouts