Motor System Pain

Question 1

What is the vicious cycle theory of pain and motor control?

Answer 1

• muscle activity => increases in pain => ischaemia + accumulation of pain-producing agents

Question 2

What is another name for the viscous cycle theory

Answer 2

• pain-spasm-pain cycle

Question 3

What are the steps involved in the vicious cycle theory?

Answer 3

• pain stress
• muscle tension
• decrease in circulation
• increase in pain
• even more tension
• even less circulation
• more pain
• muscle tension etc.

Question 4

What are the limitation of the vicious cycle theory?

Answer 4

• overly simplistic
• doesn’t explain increase and decrease of tone in same muscles/groups
• myalgia (muscle pain) generally has no increase in algesic (pain-producing substances)

Question 5

What is the pain adaptation theory?

Answer 5

• activity of painful muscles reduces during voluntary efforts (hypotonic)
• antagonist muscles increase voluntary efforts (hypertonic)

Question 6

What effects pain-related inhibition?

Answer 6

• Hilton’s law
• joint effusion

Question 7

What is Hilton’s law?

Answer 7

• nerves that supply the joint, supply muscles that control the joint

Question 8

What happens when a joint has effusion?

Answer 8

• neuromuscular inhibition + altered joint mechanics

Question 9

What happens if the knee joint has effusion?

Answer 9

• neuromuscular inhibition of quads => reduced tone (hypotonic)
• hamstrings increased activity => increased tone (hypertonic)

Question 10

What happens to LBP and motor control in the TVA?

Answer 10

• LBP => deficit in motor control of TVA <= due to increased cortical inhibition
• LBP => TVA unable to increase in cross sectional size when in pain
• reduction in pain -> TVA fires again
• need to remove pain first before strengthening TVA

Question 11

What happens to muscles and proprioception during pain adaptative theory

Answer 11

• strain of small joints/muscles
• local protective ‘spasm’
• alters proprioception
• deep stabilising muscles become hypertonic, weak and flaccid
• superficial muscles become hyperactive, hypertonic and guarded
• leads to ischaemic pain

Question 12

What is Torticollis?

Answer 12

• head side bends + rotates => shortening neck

Question 13

Which muscles of the next are important for strength and proprioceptive movement?

Answer 13

• deep flexors => longus colli + longus capitus

Question 14

What happens when longus colli becomes hypotonic?

Answer 14

• neck pain

Question 15

What is the craniocervical flexion test?

Answer 15

• pt lines supine
• chin + forehead level
• uninflected pressure cuff under neck => inflate to 20mmHg
• PT nods to increase pressure by 2mmHg, holds for 5 sec
• repeat up to 30mmHg in 2mmHg increments
• observe/palpate use of superficial flexors => should be able to nod without using SCM, scalenes, traps
• good for primary HAs

Question 16

What is the relationship between neck pain and migraines?

Answer 16

• neck pain > with > frequency of HAs
• chronic migraine => tension type HAs
• increased activity of neck muscles during exercise and mental tasks
• hypertrophy of rectus capitus posterior minor
• migraineuse have altered motor control + greater Co activation of flexors

Question 17

When you have an injury, patients often describe feeling stiff, describe how this mechanism comes about and how it can be helpful

Answer 17

• pain injury (Nociception) or threat
• activity in muscles
• changes in levels of nervous system
• change in behaviour in area
• increase in stiffness (less prone to injury)
• short term benefit, however, long term consequences e.g. increases load, reduces movement and variability

Question 18

What is the difference between perceived stiffness and actual stiffness?

Answer 18

• LBP patients do not have increase tone of ES muscles
• LBP patients have increased perception of back muscles feeling stiff
• LBP patients over estimate pressure on spinal muscles + detect change better
• manipulation (creaking/grinding) increases perception of stiffness

Question 19

Describe the pathway of cortical pain-related inhibition

Answer 19

• descending cortical inhibition reduces ability of muscle to fire
• results in reduced muscle strength + motor control => insufficient capacity + control of muscle to perform task => pain + reduced performance

OR

• sufficient muscle strength but not enough control to perform task => pain + reduced performance or vice versa
• have to have strength + control to perform task

Question 20

What is the problem with rehabilitation and cortical pain-related inhibition?

Answer 20

• most rehab focuses on improving strength but not descending motor control for cortical inhibition

Question 21

How do you overcome descending motor cortical inhibition?

Answer 21

• external cues rather than counting e.g. metronome

Question 22

What is loss of demarcation in the sensory homunculus

Answer 22

• smudging occurs between cortical zones of the brain and the hand becomes less clear where it starts and ends

Question 23

Where else can smudging happen?

Answer 23

• motor cortex in patients with recurrent low back pain

Question 24

What happens in the cortex (sensory + motor) when playing sport?

Answer 24

• visual cortex identifies object, size, direction, velocity
• Pre motor cortex develops motor program that will allow approaching the ball and hitting back
• motor cortex sends signals to spinal cord to activate and inhibit arm+ leg muscles
• cerebellum fine tunes movements => proprioceptive information from peripheral sensory receptor

Question 25

What does the basal ganglia do during motor programs?

Answer 25

• initiates motor patterns + recalls learned movements

Question 26

What does the amygdala/hippocampus do during motor programs?

Answer 26

• amagydala => adjusts HR, breathing + homeostatic mechanisms
• amygdala => hypothalamus activated for motivation
• hippocampus => records details in long-term memory

Question 27

What happens to motor programs when a patient is in pain?

Answer 27

• motor programs = every day
• pain => alters deep + superficial muscles
• painful muscles ‘protected’ by agonists
• inhibited muscles become wasted, fatty and weak
• new motor-program becomes hard-wired
• movements pre-tempted by running ‘painful’ neuro tag

Question 28

How does manual therapy help motor control?

Answer 28

• pain => maladaption + reduced proprioception
• fear => influences recruitment, strength + endurance of muscles
• treatment aimed at restoration + control of movement
• MT improves proprioception + range of moment + graded exposure to previously painful stimuli

Question 29

How do you help patients in pain?

Answer 29

• set goals that are comfortable
• do not exacerbate pain
• address fears on exercise + movement
• set goals
• use imagery (mirrors)
• slowly increase load/duration
• muscle strengthening with isometric before eccentric ex
• use a metronome to avoid anticipation