Emergence walking

Question 1

Walking: History

Answer 1

Taub & Berman (1968):
* constraint induced or forced use. “forced use” of a sensory deprived animal by constraining the other limb.
* Conclusion: rehabilitate by engaging the limb in activities

Fossberg (1977):
* muscles of cats with transected spinal cords have the same muscle activity in normal cats. Cats are recruiting motor units.
* conclusion: lower limb activity can be activated under cetain situations.

Late 1800s: Sherrington Neural Control of Walking
* severed SC: hind limbs continued alternating movements
* conclusion: do not need influence of higher brain centers to walk
* monkeys: eliminated sensory info and resulted in rhythmic walking pattern
* Conclusion: removing sensory input on both sides resulting in pattern remains

Question 2

*Motor task that involves…

Answer 2

1. strength sufficient for the support of body weight: GRF. Stability before mobility.
2. Stable enough to compensate for balance shifts. Maturation of the balance system.
3. Adaptations to uneven surfaces.

Question 3

Prenatal to postnatal stepping

Answer 3

• infants kick or step in utero
• at birth, elicit stepping pattern
• disappears at 2 months
  -reappers at the start of walking
  -continue kicking in supine
  -same pattern in standing

Question 4

Progression from stability to mobility

Answer 4

1. standing with assistance
2. standing alone
3. mobility with 2 hands
4. independent mobility

Question 5

Gait is there an average time frame for emergence?

Answer 5

On average, infants begin to walk w/o assistance from 9-15 mo
* large time frame
* motor delay in gait is at 18 mo

Myelination occurs from caudal (head) to distal (legs)-at 9 months reaches the lower legs
* critical factor in gait emergence

Question 6

Development of gait factors 1st yr

Answer 6

Components are developed from birth to 12 mo
* locomotion pattern (CPG): innate
* postural control in standing (at tabletop)
* motivation and navigation toward a distant object
* standing on one leg: stance phase stability (cruising)
* high guard posture

Question 7

Components necessary for gait emergence

Answer 7

Motor production
* Stabilization
* Force or power

Sensory Apparatus
* vision
* vestibular
* somatosensory: tacile/pressure & proprioception

Question 8

Sensory Contributions

Answer 8

Need all 3 to walk independently w/o thinking

Vision
* balance, steering, and avoiding obstacles
* visial optic flow
* stabilizing head: vision vertical

Vestibular system
* stabilization of head
* postural control

Somatosensory/proprioception
* feedback of body awareness
* tacile feedback from ground

Question 9

First steps

Answer 9

• high step pattern
• wide BOS
• no push off
• knees flexed at stance
• upper limbs: no arm swing and high guard
• short steps
• synchronized patterns in legs
• waddling pattern

Question 10

Walking Development

Answer 10

Development from the immature pattern of primary stepping

Gradual emergency of normal gait
* the joints demonstate increasinf complexity
* “synchronization”=moving simultaneously
* to “dissociation”=moving joints individually
* Syncrhonization (4.5 mo before first steps) –>dissociation (4.5 mo later after first steps)

Controlled fall: infants are leaning forward when walking, forward COM

Question 11

Progression of gait

Answer 11

Ability to control equilibrium responses (postural control)
* falls forward with hands extended
* falls backwards on bottom

Ability to control single limb stance (32% at one year)
* able to change directions 15-18 mo
* heel strike at 2 years of age
* mature at 3 years of age with small improvements until 7 years if age
* COM stabalizes 7 year years of age

Question 12

Other skills associated with walking

Answer 12

• Avoiding obstacles: stepping over objects, walking around objects, vision (downward gaze)
• protective responses: parachute and protective extension
• distance: knowing how far one travels
• navigation: moving from place to place using memory and landmarks
• cognitive processing: dual task emerging

Question 13

Sensory contributions part 2

Answer 13

• stretching of hip flexors
• step length, appropriate frequency
• contributions of loading the limbs
  -pressure sensors
  -practice standing for long periods

Question 14

The aging human: muscular system

Answer 14

• loss of muscle mass after age 60
• especially type II fibers
• may lead to sarcopenia (loss of muscle mass) in the elderly (increased protein breakdown, decrease protein synthesis)
• muscle changes to fat when there is disuse
• USE IT OR LOSE IT

Question 15

*Skeletal system in older adult

Answer 15

• loss of vertebral body height (especially T/S with forward flexed posture)
• increased risk of fracture

Question 16

The loss of tactile or cutaneous receptors

Answer 16

Disease
* type II diabetes with sensory nerve fiber loss: loss of tactile sensation
* peripheral nerve damage
* stroke

Aging
* loss of fine touch sensation
* loss of heat and cold sensation
* loss of pain perception

Question 17

Loss of visual system

Answer 17

Loss of visual acuity:
* reading: accommodation or the lens does not bend to accommodste light
* distance

Diseases
* type II diabetes: retinal damage
* macular degeneration
* glaucoma

Question 18

Vestibular System disuse in the elderly

Answer 18

Vestibular system is a use it or lose it system
Purpose:
* Acceleration (forward/up/down)
* head rotation: speed and movement

Elderly show a loss of:
* quick acceleration in movement (constant speed: no variation)
* cervical rotation

Maintain:
* forward head posture
* forward trunk posture

Question 19

*Dulled response to protect their head

Answer 19

Protective responses
* reducsed ankle and hip strategy
* reduced speed of protective arm extension–parachute response (infant
* 20-30% lead injuries to the head

Question 20

*Gait speed & associated with dementia

Answer 20

• gait can slow down cognitive decline (O2 & glucose)
• dementia causes decreased gait speed
• ppl with cognitive decline have decreased gait speed
• with dementia you lose the feeling of wanting to go for a walk