Abnormal muscle tone/spasticity

Question 1

flaccidity

Answer 1

complete lack of resistance to passive stretch

Question 2

hypotonia

Answer 2

abnormally low/less than normal resistance to passive stretch

Question 3

hypertonia subtypes

Answer 3

spasticity + rigidity

Question 4

spasticity vs rigidity

Answer 4

spasticity is velocity dependent and rigidity is velocity independent

Question 5

LMNL typically present as hyper or hypotonia

Answer 5

hypotonia or flaccidity

Question 6

myasthenia gravis presents as hyper or hypotonia

Answer 6

hypotonia

Question 7

when can UMNL present with flaccidity or hypotonia

Answer 7

during spinal shock (temporary state)

however, it then presents as hypertonic after a few months

Question 8

UMNL typically present as hyper or hypotonia?

Answer 8

hypertonia

Question 9

is cogwheel part of spasticity or rigidity

Answer 9

rigidity

Question 10

cogwheel

Answer 10

start-stop resistance to movement as limb is passively moved through ROM

Question 11

lead-pipe

Answer 11

constant resistance to movement throughout ROM

Question 12

gegenhalten (and where is it most seen)

Answer 12

involuntary resistance to passive movement

seen in dyspraxia, apraxia, dementia

Question 13

decerebrate rigidity positioning vs decorticate

Answer 13

decerebrate: elbow EXTENSION
decorticate: elbow FLEXION

Question 14

decerebrate rigidity cause

Answer 14

damage of brainstem between midbrain and pons

Question 15

decorticate rigidity cause

Answer 15

damage of superior midbrain
or
severe bilateral lesions of cerebral cortex

Question 16

how does an EMG look in spasticity

Answer 16

it INCREASES linearly with speed of movement

Question 17

clonus

Answer 17

involuntary, repetitive rhythmic reflex contraction of a single muscle group

Question 18

clasp knife phenomenon with catch/give

Answer 18

initial resistance to passive stretch/movement followed by decreased resistance as movement continues

Question 19

is all spasticity bad?

Answer 19

no, can help with posture, muscle mass, gait, etc.

Question 20

what type of neurophysiological contribution of spasticity involves pyramidal tracts and extrapyramidal tracts?

Answer 20

supra-segmental contribution

Question 21

how do pyramidal tracts contribute to spasticity

Answer 21

inhibition not working on the corticospinal tract causes exaggerated movement and tone

Question 22

how do extrapyramidal tracts like DRT, VMRST, and VST contribute to spasticity

Answer 22

DRT = inhibitory center
VMRST + VST = excitatory centers

Question 23

what 2 areas of the cortex must simultaneously have a legion to produce spasticity

Answer 23

primary motor cortex
premotor cortex

Question 24

what happens when a pt has a legion only in the primary motor cortex

Answer 24

weakness and decreased reflexes

Question 25

a legion to what part of the internal capsule can cause spasticity

Answer 25

ANTERIOR limb

Question 26

the ventromedial reticular formation is also known as the....

Answer 26

inhibitory system

Question 27

where is the ventromedial reticular formation located? what controls it?

Answer 27

medulla premotor cortex

Question 28

function of ventromedial reticular formation

Answer 28

inhibit spinal stretch reflex via descending output of dorsal (lateral) reticulospinal tract

Question 29

excitatory system FACILITATES _____ and _____, while INHIBITING ______

Answer 29

facilitates = stretch reflex + extensor tone inhibits = flexors

Question 30

lesions of primary motor cortex must also involve ____(2)____ to cause spasticity

Answer 30

premotor and supplementary motor areas of the brain

Question 31

what type of neurophysiological contribution of spasticity involves renshaw cell inhibition

Answer 31

segmental spinal contribution

Question 32

with increased fusimotor drive, there is often an overactive ____ motor system. what does this cause?

Answer 32

gamma (Y) this causes muscles to respond excessively to stimuli

Question 33

spinal shock

Answer 33

within 24 hrs of a SCI, no DTR can be elicited

Question 34

gamma (Y) motor neurons are also known as

Answer 34

fusimotor neurons

Question 35

1a presynaptic inhibition

Answer 35

constant release of GABA decreases 1a afferent ability to release neurotransmitters

Question 36

how is immobilization beneficial in 1a presynaptic inhibition

Answer 36

casting can help reduce spasticity by long-term stretching out the spastic muscle

Question 37

1a reciprocal inhibition

Answer 37

alpha MNs cant tell antagonist muscle to relax this inhibits co-contraction relationship of the agonist/antagonist

Question 38

1b non-reciprocal inhibition (autogenic inhibition)

Answer 38

GTOs are unable to communicate to its muscle belly to relax when the tendon is being stretched

Question 39

renshaw cell (interneuron) inhibition

Answer 39

inhibits gamma (Y) MNs and 1a interneurons (recurrent inhibition)

Question 40

what neurotransmitter excites renshaw cells

Answer 40

ACh

Question 41

neuroplasticity

Answer 41

functional reorganization within spinal circuits

Question 42

UMN injury neuroplasticity presentation

Answer 42

abnormal motor control to try to adapt to new circumstances --> contributes to spasticity

Question 43

what type of changes can occur to constantly contracted soft tissue

Answer 43

contractures (which WORSENS spasticity)

Question 44

non-nociceptive stimuli that can trigger spasticity

Answer 44

touch/pressure (cutaneous) bladder, bowel, infection, etc (visceral)

Question 45

what tool is most commonly used to measure spasticity

Answer 45

Modified Ashworth Scale (MAS)

Question 46

1 vs 1+ on MAS

Answer 46

1 releases or has minimal resistance through end ROM vs 1+ has minimal resistance throughout the remainder of ROM (no release)

Question 47

2 on MAS

Answer 47

increased muscle tone through most ROM but part is easily moved

Question 48

4 on MAS

Answer 48

affected part is rigid in flexion or extension

Question 49

3 on MAS

Answer 49

considerable increase in muscle tone AND pROM is difficult

Question 50

spasticity presentation on NCVs vs EMGs

Answer 50

NCVs show normal EMGs show increase (measures central issues)