Typical Motor Development

Question 1

Why is motor behavior so important from a developmental perspective?

Answer 1

• Origins of complex thought and behavior lie in action)
–In order for a baby to learn they have to explore their world (motor drives so many other things)
–Active participation engages multiple sensory processes, more feedback provided

• Increased cognitive, social, communication opportunities
• Dynamic skilled movement required for primitive reflex integration
• Provides spatial and body awareness
• Self efficacy/peer relationships
• Later academic achievement

Question 2

Reflexes and what is the controversy

Answer 2

• Evolutionarily adaptive (motor programs you get for free)
• Automatic motor response to a stimulus - not so high to the cortal level

• Controversy:
Are these inhibited and integrated/disappear or are they early form of later PRESERVED movement patterns

• Stepping Reflex!

Question 3

Do all reflexes leave us as we get older?

Answer 3

No, there are some reflexes that remain. the withdrawal reflex we use as adults

Also when someone is older you might see primitive reflexes coming back. They did not just reappear, there was damage to where new skilled were learned and built. So, primitive reflexes might present again.

Question 4

Righting Reactions

Answer 4

–Ventral suspension
–Lateral suspension

tells you about vestibular system and muscle strength

Question 5

• Protective Reactions

Answer 5

–Parachute testing - baby puts arms down in front

Question 6

What are spontaneous movements?

Answer 6

• They are movements that happen in utero.

- CPG (central pattern generator) - movements that are stored and produce rhythmic patterns w/o cortical input

Question 7

Why are spontaneous movements important? What modulates them?

Answer 7

• Burst movements from motor neurons facilitate axonal migration
• Spontaneous movements facilitate neural organization!

• Modulated by spinal and supra-spinal neural circuits (CPGs)

Brain shaped by movement

Question 8

Name 3 important ages for spontaneous movements

Answer 8

• Head and trunk observed 7 weeks PCA (post conceptual age)
• General movements as early as 9 weeks PMA (postmenstrual age)
• Full fetal repertoire available by 16 weeks PMA

Question 9

What are GMs?

Answer 9

Generalized movements that you see in the first few months of life

2 types: Writhing and Fidgety

• Initially little variability, but after few days variability increases with spatial, temporal, body parts
–Coincides with synapse formation at cortical plate (early around 2 months)!
(head and trunk to all limbs)
-fidgety happens around 4-5 months

• GMs replaced by volitional movement
• Variation seen with co-occurrence of different developmental phases, ‘regression’
• By 18 months, all basic motor functions are in secondary variability phase –will be refining

Question 10

Fidgety movements are related to activity in what part of the brain?

Answer 10

• Fidgety movements related to activity in BG, cerebellum, parietal, temporal and occipital cortices

• happens around 4-5 months

Question 11

Why is rotation important?

Answer 11

You want to get transverse plane movement in very soon

Question 12

*Writhing characteristics

Answer 12

large amplitude

slow velocity

high complexity rotational
-passes through the body

with rotation through the trunk

has an eb and flow

(then transitions to next GM)

Question 13

*Fidgety characteristics

Answer 13

No eb and flow - constant

small amplitude

high velocity (fast)

Distal rotation
-feet on feet, hands on hands

hips and shoulders popping off

Question 14

If a baby is not fidgety what could this mean?

Answer 14

This is abnormal - this is important for screening. But if you are going to use it you have to be trained in it

Baby could have CP

People trained in GMs are highly able to predict if a baby might have CP and then services can be accessed early so you change the trajectory of babies outcome

Question 15

Why is generalized movement so important and what do GMs tell you?

Answer 15

Good for screening (highly predictive)

movement drives a lot of other systems

GMs drive axonal reorganization

Transition and different types of movements coincide with development of other parts of the brain (cortical vs brainstem development)

Directly relates to what is going on with brain development. Gives information about if baby is developing from a neurological standpoint in an appropriate manner

Question 16

How can we conceptualize primitive reflexes and their utility?

Answer 16

free motor program that we are born with until we develop more skills and build upon them.

ex: if ATNR is obligatory and baby is stuck this is a flag. Or persistant well after the time you expect to see it.

Question 17

what is the the importance of sub-skills components

Answer 17

All the pre-skills we want to make sure that they are in the appropriate alignment and recruiting the appropriate musculature because we need strength and alignment for the actual skill.

ex: in order for a baby to go from supine to prone they need to develop abdominal strength and transverse plane strength

Question 18

Stages of Early Motor Development: what functional head control skills happen at birth, 2 months, 3 months, and 3-4 months

Answer 18

Birth:
• can right head from full flexion or extension when held in vertical upright, sustain 1-2 seconds

2months:
• Supported sitting can sustain head in frontal plane midline, but gaze is downward

3 months:
• Sustained upright head control in supported vertical • Start to rotate head in this position
• Prone –will bring arms beneath chest for propped on forearms for head elevation

• 3-4 months: stable head in prone allows for development of binocular vision for depth perception

Question 19

Stages of Early Motor Development: what functional UE control skills happen at birth, 2-3 months, and 6

Answer 19

• Birth:
–spontaneous movements = writhing

• 2-3 months:
–Spontaneous movements = fidgety, ballistic swipes and swats
• These reciprocal and large range movements herald goal directed reaching

• 6 months:
–Independent sitting
• Learned to shift weight caudally and
• Developed anticipatory stabilization control of pelvis and LEs when moving head and UEs in supine

–More extension in prone • More freedom for mobility and play

Question 20

Why is it improtant for a baby to have time in prone

Answer 20

time in prone is important in visual function (relationship bw vision and motor)

Builds strength

Question 21

Why is is important for a baby to have fine LE control

Answer 21

• When pelvis and trunk are more reliable stabilizers, LEs have more freedom to move for independent locomotion

Question 22

What is the amount of time that a baby needs to work on their walking? And how does their walking improve?

Answer 22

At least 6 months

more DOF
heel strike
arm swing
inc step length and speed

Question 23

Upright Trunk Control
Birth
2-3 months
6 months

Answer 23

• Birth: –spontaneous movements = writhing–Prone and side lying –hand to mouth
• 2-3 months:–Spontaneous movements = fidgety, ballistic swipes and swats • These reciprocal and large range movements herald goal directed reaching

• 6 months:–Independent sitting
•–Learned to shift weight caudally and
– Developed anticipatory stabilization control of pelvis and LEs when moving head and UEs in supine (so they can use hips and legs as a base of support )

–More extension in prone • More freedom for mobility and play

Question 24

Development of locomotion - prenatal

Answer 24

–Limb movements emerge cephalocaudal forelimbs prior to hindlimbs

–Intralimb coordination and then interlimb coordination

Question 25

What are some pre-locomotion stages

Answer 25

• Baby is placed in standing
–AP oscillations
• Baby pulls to stand - want baby to use flexors (8-10 months)
–Varied play
–COM posterior to heels with vertical tibia (important for gait cycle)
• Baby cruises (lateral plane movement)
–UE support should be for balance vs WB
• Independent stance
• Stepping

Question 26

Early walking characteristics are?

Answer 26

• WBOS
• Increased hip and knee flexion
• Full foot IC in PF
• Short stride
• Increased cadence
• Relative foot drop in swing
• Co-contraction (freezing DOF)

Question 27

What is the amount of time that you see the greatest change in baby’s gait?

Answer 27

6 months

Question 28

Determinants of Walking: What separates the mature from immature walkers

Answer 28

1. Duration of single limb stance
2. Walking velocity
   - - Cadence
   - - Step length
3. Ratio of pelvic span to ankle spread (Base of Support starts to narrow)

Question 29

*Maximum Time for Practice Required for a Consistent Heel Strike

Answer 29

1 year

Question 30

*Maximum Time for Practice Required for a NBOS

Answer 30

11 months

Question 31

*Maximum Time for Practice Required for a Reciprocal Arm Swing

Answer 31

11 months

Question 32

Some Atypical Development Characteristics

Answer 32

• Lack of variation/variability in GMs
• Don’t achieve milestones
• Stereotypical movement
• Postural dysfunction –limited repertoire of adjustments!

Question 33

Refinement of Gait from Birth to 9 months

Answer 33

• Increasing contribution of fat to body mass
• Changing body proportions: legs growing at faster rate than head-rump gravitational and inertial forces
• Hip flexion ‘contractures’, hip ER>IR
• Femoral anteversion and antetorsion present •
Knees in genu varum

Question 34

Refinement of Gait from 9-15 months

Answer 34

• WBOS
• Hip Abduction, flexion, slight ER
• Walking by falling –have more control in lateral than anterior-posterior planes

Question 35

Refinement of Gait from 18 to 24 months

Answer 35

• Varum resolved
• Improved hip strength –decreased BOS • Ankle PF and knee flexion moments –More control in anterior-posterior plane
• Descending COM
• Heel strike: neurological maturation, change in body structure, improved motor control, base of support, stability, strength
• Decreasing co-contraction • Ability to control forces with eccentric control (decelerate!)

Question 36

With Practicing walking babies gain

Answer 36

• Extensor strength to support single limb stance
• Dynamic balance
• Postural control