VII- Neuron Dysfunction

Question 1

UMN lesions paralyze

Answer 1

movements
-single possible movements

Question 2

peripheral lesions paralyze

Answer 2

muscles
-so by destroying the nerve to the muscle the movements it does also deletes

Question 3

hallmarks of UMN damage

Answer 3

1. muscle weakness
2. spastic paralysis/weakness
3. inc muscle tone/hypertonia
4. exaggerated reflex/hyperreflexia

Question 4

clinical signs of UMN lesions

Answer 4

1. clonus
2. clasp knife effect
3. pos babinski sign

Question 5

hallmarks of LMN damage

Answer 5

1. muscle weakness
2. flaccid paralysis/weakness
3. muscle wasting/atrophy
4. hypotonia/dec tone
5. reduced or absent reflexes
6. fasciculations/spont muscle contractions

Question 6

hallmarks of peripheral damage

Answer 6

1. paralysis
2. atrophy
3. hypotonia
4. fibrillations
5. fasciculations
6. areflexia

distinguish from LMN by sensory involvement and fibrillations

Question 7

facial lesions

Answer 7

corticobulbar inputs bilaterally to upper half and contralat to lower
-UMN lesion contralat quarter lower face
-LMN lesion entire contralat half

Question 8

extensor flexor imbalance

Answer 8

arms xs flexor tone + legs xs extensor tone = altered gait

UMN lesion

Question 9

clonus

Answer 9

rapid, rhythmic contractions elicited by stretch of muscle
-over active stretch reflexes OR loss of inhibition from cortex = inc gamma neurons

Question 10

clasped knife phenomenon

Answer 10

inc resistance to passive stretch of elbow extensors as moved into flexion > sudden collapse of resistance = easy flexion

Question 11

hypertonicity/spasticity

Answer 11

inc resistance of flexors as extending esp with rapid attempts at passive movement
-from corticospinal tract disease

Question 12

spinal muscular atrophy

Answer 12

SMN1 dysfunction = motor neuron death of LMNs
-weakness in upper legs, arms, trunk

Question 13

myasthenia gravis

Answer 13

autoimmune so antibodies target acetylcholine receptors at NMJ
-weakness, rapid fatigue inc with exercise
-maybe respiratory failure, swallowing, breathing problems

Question 14

ALS

Answer 14

both LMN and UMN so
-weakness, twitching, atrophy + stiffness, cramping

Question 15

phases of spinal shock

Answer 15

1. 0-1 days- areflexia/hyporeflexia, loss of descending nervous stim
2. 1-3 days- initial return of reflexes from super sensitivity
3. 1-4 weeks- hyperreflexia from new synaptic growth
4. 1-12 months- hyperreflexia esp cutaneous from growth of long axons, mass reflex