Neuro Screening

dorsal afferent

sensory portion spinal nerve root

ventral efferent

motor portion spinal nerve root

reflex arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

receptor, sensory neuron, dorsal root, integration center, ventral root, motor neuron, effector, response

reflex arc pathway

central nervous system

brain and spinal cord, plans movement

upper motor neuron (UMN) lesion

injuries to central nervous system are called what

UMN lesions

stroke, spinal cord injury, traumatic brain injury, multiple sclerosis are all examples of what

peripheral nervous system

execute the movement, cranial and spinal nerves and autonomic nervous system

lower motor neuron (LMN) lesion

injuries to peripheral nervous system are called what

LMN lesion

peripheral nerve trauma, radiculopathy, guillain barre syndrome are all examples of what kinds of injuries

dermatomes

sensory distribution of any given nerve root (area of skin)

myotomes

muscle or groups of muscles innervated by a specific motor nerve

systemic or central cause

You bilaterally test dermatome/myotomes, you find that both sides (symmetrical finding) are weak. What is thought to be the cause

peripheral or nerve root

You bilaterally test dermatome/myotomes, you find that one side (asymmetrical finding) is weak compared to the other. What is thought to be the cause

C1

only spinal nerve without a dermatome

Dermatome: seated, palms up, skin exposed, eyes closed

Myotome: Seated (LE can be supine)

patient position and conditions during dermatome and myotome testing

test about and below suspected level

if diminished sensation is discovered during a dermatome test, what should be done to confirm the localization and help map out the full area of reduced sensation

affected

a root lesion causes sensory disturbances in the region supplied by the ___________ root

weakness (not paralysis)

most muscles are innervated by more than one nerve root, this causes what to happen to a muscle if a nerve root injury is the issue

paralysis (inability to contract)

if a peripheral nerve lesion is present what could happen to the muscle

5 to 10 seconds

how long must you apply force during a myotome test

weakness without pain

what makes myotome testing different than musculoskeletal testing

break

myotome testing is a make or break test

compare with bilateral limb, then test above and below suspected level of weakness

if you identify a weakness of muscle, what should your next 2 steps be

strength quality (force) and timing (delay or fatigue)

what are two things to note when myotome testing in regards to fatigue

nerve root level

myotome testing has alternative tests that target the same _________________ via different muscles. This is to confirm true weakness vs. fatigue or poor effort

deep tendon reflex

involuntary muscle contraction in response to striking muscle tendon with reflex hammer; test used to determine whether muscles respond properly

monosynaptic

deep tendon reflexes are considered what type of reflex because they include one sensory and one motor neuron and communicate within the anterior horn of the spinal cord

no, stay at level of spinal cord

do DTR's involve the brain? Why

0

no reflex grade

1+

minimal or depressed reflex grade

2+

normal reflex response grade

3+

overly brisk reflex response grade

4+

extremely brisk reflex response grade

- clonus

clonus

rapidly alternating involuntary contraction and relaxation of a muscle in response to sudden stretch

hypotonic DTR (0 or 1+)

- Frequently result from injury or compression along the nerve pathway, including at the nerve root.

- Lower motor neuron involvement

- unilateral: not common to have same lesion at the same root level on right and left sides of the body.

- ex: Bulging or herniated disk, stenosis of intervertebral foramen, peripheral nerve injury

hypertonic DTR (3+ or 4+)

- sign of CNS pathology

- Upper motor neuron involvement

- unilateral or bilateral

- ex: spinal cord injury, stroke

- also called hyperreflexia

tendon on slight stretch, patient relaxed, unaffected side first

list three things to remember when testing reflexes to make sure they are valid tests

pathological reflexes

- normally not present in adults, presence indicates an upper motor neuron lesion (UMNL)

- do not want to see these

neuro screen

brief but systemic examination used to identify potential involvement of the nervous system contributing to a patients symptoms

upper motor neuron lesion

affect the brain and spinal cord