Lecture 3: Control of gait across life span

Question 1

Neural control of gait

Answer 1

•	Spinal cord
•	Cortical control
•	Basal ganglia and thalamus
•	Cerebellum
•	Sensory systems
o	Vision
o	Vestibular
o	Somatosensory
•	Cognitive input

Question 2

Spinal cord

Answer 2

• Contains central pattern generator (CPG)
• CPG responsible for motor pattern- rhythmical sequence
• When threshold is met, CPG triggered, automatic gait activated

Question 3

Cortical control

Answer 3

• Enables variations in gait to adapt to goals, obstacles and environment
• Sup motor area, pre-motor cortex, cingulate motor area
• Via descending corticospinal tract (85% crossover to lateral CST)
• Activates voluntary muscles

Question 4

Basal ganglia and thalamus

Answer 4

• Automatic modulation to sensory input
• Via brainstem, reticulospinal tract, vestibulospinal tract
• Activates voluntary muscles

Question 5

Cerebellum

Answer 5

• Receives and interprets sensory info via afferent spinocerebellar and vestibulocerebellar tracts
• Modulates activity in thalamus, brainstem nuclei and vestibular nuclei
• = subconscious modulation of motor neurons and coordination

Question 6

Vision

Answer 6

• Info transmitted via optic nerve to thalamus and visual cortex
• Dominant sensation to maintaining posture
• Aligns body
• Speed of movement
• Identify potential obstacles

Question 7

Vestibular

Answer 7

• Vestibular apparatus detects head movement via vestibulocochlear N
• Maintain balance and gaze stabilisation

Question 8

Somatosensory

Answer 8

• Cutaneous input from feet
• Spindle fibres and GTO
• Via spinothalamic tract to sensory cortex and spinocerebellar tract to cerebellum

Question 9

Cognitive input

Answer 9

• Frontal, prefrontal and parietal cortices
• Intention and initiation
• Self-awareness
• Planning and dual-tasking
• Response inhibition/response monitoring

Question 10

Effect of cognitive deficits

Answer 10

• Impulsivity
• Difficulty with obstacles
• Reduced ability to talk and walk
• Struggle carrying objects while walking

Question 11

Normal gait cycle

Answer 11

• Bipedal with alternating, symmetrical limb movement
• Begins initial contact of one foot and ends with contact of same foot again
• Two phases: stance phase (60%) and swing phase (40%)

Question 12

Stance phase

Answer 12

1. Initial contact- heel strike (~2%)
2. Loading response- double support until contralateral toe-off (~8%)
3. Mid stance- single support (~40% with 4.)
4. Terminal stance- single support (~40% with 3.)
5. Pre swing- toe-off including double support (~10%)

Question 13

Swing phase

Answer 13

1. Initial swing
2. Mid swing
3. Terminal swing

Question 14

Clinical gait measures

Answer 14

• Velocity- average speed
• Cadence- steps/minute
• Step length
• Stride length

Question 15

Age on gait

Answer 15

• Reduced gait velocity and cadence
• Shorter step length and stride length
• Reduced single support phase and swing phase
• Greater step width (wider BOS)
• Reduced strength of push off
• Reduced dual-tasking

Question 16

Pain on gait

Answer 16

• Asymmetry
• Altered ROM
• Altered stance times
• Altered BOS

Question 17

Functional impact of gait pain

Answer 17

• Muscle inhibition
• Impact on balance = falls risk
• Use of medications and gait aids
• Reduced participation