PD - Reflexes

what are reflex actions?

involuntary response that involves afferent and efferent nerve fibers

all components need to be intact:

• sensory nerve fiber

• motor nerve fiber

• spinal cord snapse

• neuromuscular junction (NMJ)

• muscle fibers

path of reflexes

reflex hammer hits patellar tendon → stretch receptor in muscles, sends message to to dorsal ganglia → innervates with cell body in dorsal root ganglion → motor neurons are activated → activation to the muscle → extension of knee joint

what are the grading for reflexes?

0 = absent

1 = reduced (hypoactive)

2 = normal

3 = increased (hyperactive)

4 = clonus

what are the reflexes evaluated for practical exam?

• UE

  • biceps

  • triceps

  • brachioradialis

• lower extremity

  • patellar

  • achilles

what should you do if the reflex response is different from one side to another after using the same stimuli and magnitude and location (one more prominent than the other), what do you do?

recommended to reassess

brachioradialis reflex*

C5-C6*

biceps reflex

C5-C6

triceps reflex

C6, C7, C8 (mainly C7)

patellar reflex

L3-L4

achilles reflex

S1 (use handle of the hammer)

what is clonus?

rhythmic series of muscle contractions induced by stretching the tendon

where/when do you see clonus the most often?

most seen in the ankle with sudden dorsiflexion and light pressure on the sole

what are cutaneous stimulation reflex?

reflex stimulated by light touch of skin that produces a localized muscle twitch

upper abdominal reflex

t8-10

lower abdominal reflex

t10-12

cremasteric reflex

L1-2

plantar reflex/babinski

L5-s1 (looks at UMN lesions)

what is a positive finding for babinski reflex?

toes curl up and fan out when you use something underneath the foot

anal reflex

S4-5

what is the sucking reflex?

sucks in response to something in its mouth

disappears by 3-4 months

what is the rooting reflex?

when a sensation is placed at the corner of the mouth, the head will turn to that side and the mouth will open

• required for infants to find source of food

• typically disappears by 6m

what is the grasp/palmer reflex?

place finger in palm of hand and the child will reflexively grab this

• begins at 32 weeks gestation

• light touch of palm produces involuntary flexion of fingers

• disappears by 3-4 months

what is tonic neck (neonatal reflex)?

when head turned to side, arm and leg on that side go straight

• lost by 2-3 months of age so infant can roll over

what is the step reflex?

• rub top of foot which causes flexion of knee to bring foot up

• press down on surface and it will cause infant to move leg up/down in “walking” movement

• disappears around 2-4 months of age

what is the babinski reflex (neonatal reflex)?

• stroke lateral aspect of foot causes extension of great toe, fanning of toes, and flexion at knee and hip

• disappears around 4 months

what is the moro reflex?

• hold infant and support head. allow head to drop 1-2 cm suddenly and infant will abduct at shoulder and hands usually spread apart

• disappears by 6 months of age

what is the pronator drift?

assess the corticospinal tract, do after you assess motor strength

both arms out to see if they pronate, if you don’t get an immediate response, you can tap the arms

alternating rapid movements

assessing coordination from one extremity to another

UE: finger to nose or palm up and down

LE: tap their feet on footrest or head

what is the romberg test?

• evaluates position sense

• stand with feet together with eyes open, then close eyes and see if they sway

what is a positive romberg test?

patient loses balance

if positive, you can have pt repeat test legs slightly apart and push on shoulders or you can have them stand on one foot at a time

what are the phases of gait?

stance phase and swing phase

what is the stance phase?

60% of gait cycle, when feet are in contact with ground

• heel strike

• support

• toe-off

what is the swing phase?

40% of the gait cycles, includes when foot is in air (leg lift) and swinging forward in preparation for the next step

what are non-neurologic causes of gait abnormalities?

• pain

• orthopedic deformities

• impaired vision

what are neurologic causes of gait abnormalities?

• sensory deficits

• myelopathy

• infarcts

• parkinson’s

• metabolic abnormalities

what is ataxia and what can cause it?

• uncoordinated gait with reeling and instability

• noted in cerebellar disease, loss of position sense, and intoxication

what is spastic hemiparesis related to/caused by?

corticospinal tract lesion

what is spastic hemiparesis?

poor control of flexor muscles during swing phase

• affected arm remains flexed and immobile

• affected leg extensors are spastic

• drag toe, circumduction

what causes scissors gait?

spinal cord disease

what is scissors gait?

• bilateral lower extremity spasticity

• stiff gait with cross of legs when stepping forward

what is steppage gait caused by?

peripheral lumbar radiculopathy (L4-L5 nerves affected), seen in foot drop

what is steppage gait?

dragging foot or slapping of foot after lifting leg

what causes parkinsonian gait?

basal ganglia defects

what is parkinsonian gait?

• stooped posture, flexion of head, arms, hips, knees

• slow to start, short, shuffling steps with hastening

• decreased arm swing

what is cerebellar ataxia?

staggering gait, unsteady with feet wide apart, difficulty on turns

what is sensory ataxia?

• loss of position sense

• gait is unsteady and wide based

• patients often look at floor when walking

what can cause sensory ataxia?

b12 def, diabetic neuropathy, problems with sensory