Life Span Mobility Pediatrics

Prenatal Development

◦ Alternating leg movements by 16 weeks in utero

◦ Development in utero:

• Cephalocaudal sequence of development

◦ At birth:

• Neural circuitry for gait is present but the postural system is too immature for normal gai

Newborn to 2 months

◦ Thrusting arms and legs

◦ Turning from side to back

◦ Weight bearing (2 months)

◦ Stepping reflex present at birth to 2 months

• It stops…. based on the different theory, there’s a different explanation for why. Evidence to suggest that this immature stepping is organized below the brainstem

◦ With maturation, the pattern comes under more control from higher centers in the brain (modulation of the Central Pattern Generators)

4 Months

◦ Props on forearms

◦ Rolling from prone to supine

6 Months

◦ Pushing head and abdomen up

7 Months

◦ Rolling from back to stomach: Starts with a log-roll.. Will shift to segmental rolling later

8 Months

Pulls forward with arms (crawling)

9 Months

◦ Creeping (on all 4’s)

◦ Begins to raise to standing (pulling up)

◦ Segmental rolling

10 Months

Cruising and stepping with trunk support

11 Months

Up to 4 steps forward with one hand-held

12 motnhs

Begin walking alone (really ~9-12 months)

◦ Wide BOS

◦ Slow velocity

◦ Short swing phase

◦ Long double-support phase

◦ Start with arms held high (high arm guard)

◦ Lean forward for momentum

◦ Muscle in limbs co-contracted (stiffening effect)

◦ Short steps

◦ Flat-foot initial contact

◦ Toes turned out

All descriptors point towards what area of weakness?

Poor balance and inadequate postural (trunk and hip) stability.

What Keeps Babies from Walking Until 9-12 Months?

◦ Answer: Postural control

◦ Primary limiting factors: **balance control and strength

14 Months

◦ Narrowing base of support

◦ Heel-toe gait pattern

◦ Emerging reciprocal pattern

Other General Descriptors of First Year of Walking

◦ High step frequency

◦ Absent reciprocal arm/leg swing

◦ Flexed knees during stance

◦ Increased hip flexion

◦ Pelvic tilt

◦ Hip abduction during swing phase

◦ Ankle pf at foot strike

◦ Decreased df during swing

Maturation of Independent Walking - 2 stages

Stage 1:

◦ 3 to 6 months after onset of walking

◦ Learning to control balance

Stage 2:

◦ 7 months to 5 years of independent walking

◦ Refining locomotor pattern

15-16 Months

Walking up stairs with support from wall or rail

17-18 Months

◦ Walking backwards

◦ Walking down the stairs with support

19-20 Months

Running (flight phase)

◦ Developed by 2nd year of age

23-24 Months

◦ Jumping forward

◦ Jumping down

◦ Walks up 4 steps without support

Other Descriptors of Gait in 2nd Year

◦ Diminished pelvic tilt and hip abduction

◦ At initial contact, a knee-flexion wave appears (with heel-toe contact)

◦ Arms down

◦ Reciprocal swing emerging

◦ Decreasing BOS

◦ By the end of the 2nd year: push-off in stance

25 Months

Walking down the steps without support

30-35 Months (**based on PDMS)

Hopping on one limb

36-41 Months (actual age depends on source***)

Galloping

57-58 Months (actual age depends on source***)

Skipping

Developmental Milestones

Walk, run, hop, gallop, skip are good indicators of balance development

7 Years of Age

◦ Most muscle and movement patterns during gait are similar to adults

◦ This means:

• Increasing single limb stance time

• Walking velocity and cadence decrease

• Step length increases

◦ This maturity appears to hinge on controlling the COM within the BOS = stability

Reactive Strategies

◦ New walkers: use feedback

◦ Co-contraction of muscles

◦ Up to 2 Years:

• Mix: automatic postural response and monosynaptic reflex response

• As they age: less monosynaptic reflex and quicker postural response

◦ By 4 Years:

• No monosynaptic reflex, only mature automatic postural responses

• Less co-activation of musculature

Compensatory stepping with balance challenge

◦ Develops 1-3 months after walking

◦ Refined by 6 months of walking experience

Proactive Strategies

◦ Feedforward is present although not mature by at least 3 1/2 y/o.

◦ By 7 years children are using mostly adult-like limb placements

Obstacle Avoidance:

◦ Children:

• adjust head and trunk first

• stride and step second (just before reaching obstacle)

◦ Adults:

• Smooth

• Change everything sooner and simultaneously

How Do We Hold that Head Up?

◦ Maintaining a steady gaze is very important to gait

◦ Up to 6 years of age:

◦ Control head en bloc (head moves with trunk)

◦ There may be an element of gaze stabilization issues with new walkers???

◦ This reduces degrees of freedom to be controlled during gait

◦ Learn to stabilize hips, shoulders, then head

◦ Bottom-up control – using somatosensory cues from the support surface

7 Years of Age

◦ Top-down organization of control

• Stabilize the head using vision and vestibular information which controls balance

◦ Head is controlled in articulated mode (more freedom from trunk)

• More mature VOR????

◦ There may be a transient dominance of vestibular processing in locomotor balance at this age of transition

Gait Initiation

◦ Younger children: anticipatory lateral tilt of the pelvis and of the stance leg present soon after start walking

◦ Older children: use less hip and knee muscles and greater ankle muscles during gait initiation

Cognition and Gait

◦ Dual-task walking:

◦ Carrying Objects - Not too difficult, even for new walkers

◦ Cognitive Tasks (memory work etc.) - Decline in quality of gait if task was too difficult

◦ Cognitive Task (executive function) -Deficits in those <7 years

• What declined? Motor, NOT cognitive performance

Cognition and Gait

Obstacle walking (executive function)

◦ Deficits in those <16 years

• What declined? Motor + cognitive performance

• They chose to do the motor task, then the cog. task

  • Young adults did the tasks simultaneously

Supine to Standing

◦ Starts with rolling to prone, up on all 4’s, pulling up on surface

◦ Transitions to pushing up through plantigrade from the floor without support

◦ By 2 to 3 years, transition from supine to partial roll to sit

◦ By 4-5 years, symmetrical sit-up pattern (this is the mature adult- like pattern)

Note: Supine to sit pattern by 4-5 years of age: considered adult-like

Sit to Stand

Quite early on children have same basic intersegmental pattern as adults

◦ Not as efficient

◦ Immediate standing balance not as good (i.e. step forward, up onto toes)

◦ Slower, less amplitude, smaller peak angular velocity of trunk flexion

Clinical Relevance of Motor Milestones?

◦ Missing motor milestone might be the first evidence that something is not right with a child

◦ This evidence often prompts further investigation

◦ Missed milestones have prompted diagnoses:

◦ i.e. CP, Arthrogryposis, genetic mutations, muscular dystrophy, autism, etc……

Based on system theories of development:

◦ “Differing motor patterns of development affect cognitive, social, and emotional patterns which then affect future developmental patterns.