Hypothesis Linking To The OSCE Cases

Question 1

Hypothesis linked to stroke: tone/ spasticity

Answer 1

Lack of descending inhibition
Velocity dependent
Spasticity due to increased stretch response and co-activity
Inappropriate muscle actibity
Secondary changes - contractures, collagen build up
Lower limb - extensor synergy
Positive neural component

Question 2

Hypothesis linked to stroke: length

Answer 2

Sarcomere had shortened
No or little action potential to activate them
Constant firing of the muscle means the sarcomere contract meaning a decreased muscle length
Affect - range of movement and force generated

Question 3

Hypothesis linked to stroke: strength

Answer 3

Weakness - disuse atrophy
The muscles aren’t being used they get smaller as there is now less motor units being recruited
Lost sarcomere, less action potential
Brain is nor sending messages to the muscles so over time secondary changes occur as there is no action potential
Negative neural component

Question 4

Hypothesis linked to stroke: sensation

Answer 4

Loss of sensation more distally
Due to somatosensory cortex and/or thalamus in the brain is damages so cant integrate the sensory information
> 60% patients present with sensory deficits

Question 5

Hypothesis linked to stroke: Proprioception

Answer 5

Due to the somatosensory and/ or thalamus in the brain is damaged so cant integrate the proprioceptive information
Impaired Proprioception in 34-64% of stroke patients

Question 6

Hypothesis linked to stroke: coordination

Answer 6

Due to the cerebellum in the brain is damaged causing ataxia
Ataxia - cerebella dysfunction
Common features of ataxia - postural unsteadiness, low tone proximally, tremor, gait abnormalities, visual changes

Question 7

Hypothesis linked to multiple sclerosis: tone/ spasticity

Answer 7

Lack of descending inhibition
Velocity dependent
Spasticity due to increased stretch response and co-activity
Inappropriate muscle actibity
Secondary changes - contractures, collagen build up
Upper limb - flexor synergy
Positive neural component

Question 8

Hypothesis linked to multiple sclerosis: length

Answer 8

Sarcomere had shortened
No or little action potential to activate them
Constant firing of the muscle means the sarcomere contract meaning a decreased muscle length
Affect - range of movement and force generated

Question 9

Hypothesis linked to multiple sclerosis: strength

Answer 9

Weakness - disuse atrophy
The muscles aren’t being used they get smaller as there is now less motor units being recruited
Lost sarcomere, less action potential
Brain is nor sending messages to the muscles so over time secondary changes occur as there is no action potential
Negative neural component

Question 10

Hypothesis linked to multiple sclerosis: sensation

Answer 10

Loss of sensation is patchy - can affect one limb, one side of the body or all four limbs
Dependent on the location of plaques in the CNS
Ascending tracts to the somatosensory cortex and/or thalamus are damaged
Less sensory information is transported to the brain

Question 11

Hypothesis linked to multiple sclerosis: Proprioception

Answer 11

Ascending tracts to the somatosensory cortex and/or thalamus are damaged
Less proprioceptive information is transported to the brain

Question 12

Hypothesis linked to multiple sclerosis: coordination

Answer 12

Ascending tracts to the cerebellum are damaged
Less coordination information is transported to the brain
Cerebella dysfunction causes ataxia
Common features of ataxia - postural unsteadiness, low tone proximally, intentional tremor; exaggerated with movements, gait abnormalities, visual changes