neuromuscular mgmt week 3

length of moment arm/length tension relationship/fiber type/cross sectional area/fiber arrangement

what are the five musculoskeletal properties?

type 1

what type of muscle fiber is slow twitch?

type 2

what type of muscle fiber is fast twitch?

motor unit

a single motor neuron and the group of muscle fibers it innervates

number/type/discharge frequency

what are the three neural properties of a motor unit?

neurologic weakness

inability or decreased ability to generate normal levels of force

upper motor neuron lesions

neurologic weakness is a major body F&S impairment associated with WHAT?

motor cortex

where do UMNs originate?

cortical lesion/descending pathway lesion/synaptic dysfunction at neuromuscular junction/damage to peripheral nerve/damage to muscle/disruption from alpha motor neurons to muscles

what are six possible causes of weakness in general?

inadequate corticospinal activation

what can a cortical lesion cause?

inadequate motor unit recruitment

what can a lesion in the descending pathways cause?

paresis/paralysis (plegia)

neurologic weakness can vary from ________ to ________?

paresis

mild or partial loss of muscle activity

paralysis/plegia

total or severe loss of muscle activity

difficulty recruiting motor units

what causes a difficulty in generating torque or movement with paralysis/paresis?

difficulty modulating motor neurons

what causes a loss of movement and power with paralysis/paresis?

force x speed

what is the formula for power?

distal

in patients who had a stroke, paralysis/paresis issues are more apparent in WHAT musculature?

structural/functional changes in muscles and joints

what are secondary musculoskeletal impairments/weaknesses?

atrophy of type 2 fibers/changes in muscle length/length tension relationships

what are three examples of secondary weakness?

decreased movement isolation/abnormal synergy/can't hold against gravity/move through full ROM/asymmetrical weightbearing

what are five things that we can observe during functional activity that lead us to suspect that neuromuscular weakness is a body F&S impairment?

scapula retraction and elevation/shoulder abduction and ER/elbow flexion/supination/wrist flexion/finger flexion

what are the five parts of the flexor synergy?

UE

what body part is typically affected by the flexor synergy?

hip extension/hip adduction and IR/knee extension/ankle PF and inversion/toe PF

what are the five parts of the extensor synergy?

LE

what body part is typically affected by the extensor synergy?

muscle tone

characterized by a muscle's resistance to passive stretch; muscle stiffness

flaccid/hypotonicity/normal/hypertonicity/rigid (stuck)

what are the five muscle tone characteristics, from "floppy" to "stiff"?

abnormal stretch reflex/hyperexcitable alpha motor neuron/changes in nonneural contributions

what are the three main contributions to increases in muscle tone (hypertonia)?

abnormal stretch reflex

the amount of excitatory input elicited by muscle stretch is increased from excitatory interneurons

hyperexcitable alpha motor neurons

may be caused by loss of descending input, postsynaptic denervation super-sensitivity, or collateral sprouting of the dorsal root afferents (least likely)

changes in nonneural contributions

less activity = muscle weakness; can't move through full ROM = change in viscoelastic properties

chronic

what type of patient has greater nonneural contributions to increased muscle tone?

type/location of pathology/chronicity

what three things does the nature of hypertonia depend on?

spasticity/rigidity/posturing

what are the three types of hypertonicity?

spasticity

what type of hypertonia is caused by damage to the pyramidal tract or the cortex?

rigidity

what type of hypertonia is caused by damage to the extrapyramidal tract or the basal ganglia?

spasticity

velocity dependent increase in resistance to passive movement; associated with exaggerated tendon jerks

hyperactive

spasticity is largely due to a ____________ stretch reflex

UMN syndrome

spasticity is one component of WHAT syndrome?

alpha motor neuron excitability/muscle tone/deep tendon reflexes

what three things are INCREASED with spasticity, due to damage to the pyramidal tract?

0

spasticity grade: no increase in muscle tone

modified ashworth scale

what do we use to measure spasticity?

1

spasticity grade: slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the ROM when the affected part is moved in flexion or extension

1+

spasticity grade: slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM

2

spasticity grade: more marked increase in muscle tone through most of ROM but affected part easily moves

3

spasticity grade: considerable increase in muscle tone, passive movement is difficult

4

spasticity grade: affect part is rigid in flexion or extension

rigidity

heightened resistance to passive movement of the limb, independent of the velocity of the stretch

flexors

what muscles does rigidity predominately appear in?

disinhibition of cerebral structures (normally inhibited by basal ganglia)

what is the cause of rigidity?

basal ganglia/descending connection with midbrain

what is the extrapyramidal system?

motor cortex/pyramidal tract/corticobulbar tract/corticospinal tract

what is the pyramidal system?

leadpipe/cogwheel

what are the two types of rigidity?

leadpipe rigidity

constant resistance to movement throughout the entire ROM

cogwheel rigidity

alternating episodes of resistance and relaxation (catches) as the extremity is moved through the range

underlying tremor

what may be present with cogwheel rigidity?

decorticate/decerebrate

what are the two types of posturing?

UE flexion/LE extension

what does decorticate posturing look like?

UE extension/LE extension

what does decerebrate posturing look like?

above red nucleus

where does the lesion for decorticate posturing occur?

below red nucleus

where does the lesion for decerebrate posturing occur?

decerebrate

what type of posturing is more severe?

hypotonicity

reduced resistance of a muscle lengthening

flaccidity

complete loss of muscle tone

peripheral nerve injury/muscular dystrophy/late stage ALS/SCI (sometimes)

what are four possible injuries that may present with flaccidity?

abnormal posturing/change in alignment/altered starting position

what are three effects of hypertonicity on resting posture and alignment?

fall into gravity

what is the main effect of hypotonicity on resting posture and alignment?

bone density/actin or myosin health

what are two examples of how an increase in muscle tone can be helpful?

ROM/alignment/endurance deficits

what are three secondary sequelae of weakness and abnormal tone?

coordination

movement trajectories of coordinated multi joint movements

straight/smooth/bell shaped velocity profiles/coordinated coupling (joints and muscles)

what are four characteristics of coordinated movements?

incoordination/discoordination

disruption of sequencing, timing, and grading

dysmetria

what is a grading/scaling problem with coordination?

dysmetria

problems judging the distance or range of a movement, poor end point accuracy

rebound phenomenon

difficulties halting or checking a movement when resistance is suddenly removed

cerebellum

the rebound phenomenon can occur with damage to what structure?

rebound phenomenon/dysdiadokokinesia

what are two timing problems with coordination?

dysdiadokokinesia

inability to perform rapid alternating movements

coactivation/impaired interjoint coordination

what are two activation/sequencing problems with coordination?

coactivation

inability to alternate between agonist and antagonist; everything is recruited, freezes degrees of freedom

impaired interjoint coordination

decompose the movement by moving one joint at a time sequentially

activation/sequencing problems

during functional movement, results in producing unnecessary movement in joints and muscles not typically involved in the task

grading/scaling problems

movement size is mismatched to the task

timing problems

inappropriately time the activation of muscles

coactivation

what coordination problem can also be seen in early learning?

dystonia

syndrome dominated by sustained muscle contractions; frequently causes twisting and repetitive movements or abnormal postures

basal ganglia

dystonia is thought to be a disorder of the ______________

tremor

a rhythmic, involuntary, oscillatory movement of a body part

resting tremor

an involuntary, rhythmic shaking movement that occurs when a person is at rest

action tremor

rhythmic, involuntary shaking that occurs during voluntary movements

resting/action

what are the two types of pathological tremors (from CNS pathology)?

choreiform movements

involuntary, rapid, irregular, and jerky movements that result from basal ganglia lesions

UE

do athetoid movements typically affect UE or LE more?

athetoid movements

slow, writing, and twisting movements

sensation

process by which our sense organs receive information from the environment

perception

the process by which the brain selects, integrates, organizes, and interprets sensory information

perception

transforming information from the senses to use to interact appropriately with the environment

peripheral nerve/spinal pathway/brain area

what three things must be intact in order to have sensation?

stereognosis

ability to identify and recognize an object by touch alone

acuity

clarity of vision, can affect the results of other tests