assessment of neurologic function

8/7/2019 ASSESSMENT OF NEUROLOGIC FUNCTION

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ASSESSMENT OF NEUROLOGIC FUNCTION

Marichelle Delos Santos RM,RN,MAN

NERVOUS SYSTEM

is an organ system containing a network of specialized cells called neurons that coordinate the actions

of an animal and transmit signals between different parts of its body

NETWORK-

means neural network or a circuit of biological neurons signaling

NEURONS-

is an electrically excitable cell that processes and transmits information by electrical and chemical

Function of the Nervous System

Controls all motor, sensory, autonomic, cognitive, and behavioral activities.

Structures of the Neurologic System

Central Nervous System

Brain and spinal cord

Peripheral nervous system

Includes cranial and spinal nerves



Autonomic and somatic systems

Neuron

Brain cells

Links the motor and sensory pathways

Monitor the bodys processes

Respond to the internal and external environment

Maintain homeostasis

Direct all psychological, biologic and physical activity through complex chemical and electrical messages

Neurotransmitters

Neurotransmitters can potentiate, terminate, or modulate a specific action or can excite or inhibit a

target cell.

Communicate messages from one neuron to another or to a specific target tissue.

Many neurologic disorders are due to imbalance in neurotransmitters.

Types:

Acetylcholine-muscle movement

Biogenic amines (thinking process)

-Dopamine -Serotonin

-Norepinephrine -Histamine

Amino acids

-GABA

-Peptides

Bones and Sutures of the Skull

3 essential components of skull:

Brain tissue-78%

Blood -12 %



CSF-10%

Monro-Kellie Hypothesis

If volume added to the cranial vault equals the volume displaced from it, the total intracranial

volume will not change

Normal ICP: 60-150 mmH20 or 0-15 mmHg

Brain

Cerebrum

Consists of 2 hemisphere

Corpus callosum

connects two hemisphere

Cerebral cortex

outer surface of the cerebrum

Basal ganglia

located deep within cerebral hemisphere

Internal capsule

white matter consisting of bundle of nerve fibers carrying motor and sensory impulses to and from

cerebral cortex

Lobes of the Cerebrum and their Functions

Diencephalon

Embedded in the brain superior to brain stem

1.Thalamus

process sensory impulses before it reaches cerebral cortex

2.Hypothalamus

regulates endocrine and autonomic function, temperature, water metabolism, appetite, emotion, sleep-

wake cycle and thirst



3.Epithalamus

includes pineal gland (secretes melatonin and inhibits LH), part of endocrine system, affects growth and

development.

Medial View of the Brain

BRAIN STEM

1. Midbrain

center for auditory and visual reflexes

2. Pons

contains the fiber tracts; contains nuclei that controls respiration

-contains pneumotaxic centercontrols rhythmic quality of respirations

3. Medulla

control cardiac rate, BP, respirators and swallowing

4. Reticular activating system (RAS)

influence excitatory and inhibitory control of motor neuron; regulatory system for consciousness

Cerebellum

Has two hemispheres

Coordination of skeletal muscle activity, maintenance of balance, posture and control of voluntary

movements

Spinal cord

Extends from medulla up to first lumbar vertebra

Gives rise to 31 pairs of spiral nerves (C1-C8, T1-T12, L1-L5, S1-S5, coccygeal nerve)

Center for conducting messages to and from the brain; a reflex center



Divisions:

Ascending (Spinocerebellar)

Carry a specific sensory information to higher levels of CNS

Spinocerebellar tracts-muscle tension and body position

Spinothalamic-pain and temperature sensation

Descending (Corticospinal)

Pyramidal tracts-

from the cortex to cranial and peripheral nerves

inhibits muscle tone

Extrapyramidal tracts-

from brain stem, basal ganglia, and cerebellum

maintains muscle tone and gross body movements

Upper motor neurons

from cerebral cortex to anterior gray column of SC

spasticity and hyperactive reflexes

Lower motor neurons

final common pathways from anterior gray column up to muscles

flaccidity and loss of reflexes

Reflex arc

Reflexes-automatic action; spinal cord mediates most reflexes

Automatic or perceptible, inhibited or conditioned

Hyperreflexia-disease or injury of certain descending motor tracts

Hyporeflexia-damage or degeneration of the sensory or motor neurons



Meninges and Related Structures

Arterial Blood Supply of the Brain

Sources of Blood supply:

1. Internal carotid arteries-anterior circulation, ipsilateral hemispheres

2. Vertebral arteries-posterior circulation, posterior fossa

Circle of Willis

act as a safety valve; arises from basilar arteries and internal carotid arteries; vascular network at the

base of the brain

is important to total brain circulation because it provides equal circulation bilaterally. If one side of the

circle of Willis is unable to supply adequate blood, the other side provides blood to the area normally

supplied by the damaged side

Cerebral arteries (2 each):

Anterior, Middle, Posterior

Jugular veins-drains the brain venous blood through dural sinuses

Cross Section of the Spinal Cord Showing the Major Spinal Tracts

Cranial Nerves

Dermatome Distribution

Peripheral Nervous system

Cranial nerves-innervate head and neck region, except the vagus nerve

Spinal nerves

Plexuses

complex cluster of nerve fibers (cervical, brachial, lumbar and sacral region)

Dermatomes

area of the skin innervated by cutaneous branches of a single spinal nerve

Somatic Nervous system

Consists of motor and sensory nerves



Controls skeletal muscles

Produces a motor response through efficient nerve fibers from

CNS which transmit impulses to the skin and skeletal muscles

Autonomic Nervous System

Functions to regulates activities of internal organs and to maintain and restore internal homeostasis

Controls involuntary or automatic body functions

Has two subdivisions, serving same organ but have counterbalancing effects; each system can inhibit the

organ stimulated by the other

Sympathetic Nervous System

originates from lateral horns of first thoracic through the first lumbar of spinal cord (thoracolumbar)

helps the body cope with events in the external environment

Functions mainly during stress, triggering the fight or flight response

Increases heart rate and respiratory rate, pupil dilation, cold, and sweaty palms

SYMPATHETIC SYNDROMES

Parasympathetic Nervous System

Consist of the vagus nerves originating in the medulla of the brain stem and spinal nerves originating

from the sacral region of the spinal cord (craniosacral)

Activates GI system

Supports restorative, resting body function through such actions as replenishing fluids and electrolytes

Anatomy of the Autonomic Nervous System

Motor and sensory pathways of the nervous system

Motor pathways

Upper and lower motor neurons

Upper motor neuron lesion



Lower motor neuron lesion

Coordination of movement

Sensory System Function

Receiving sensory impulses

Integrating sensory impulses

Sensory losses

DIVISIONS OF THE NERVOUS SYSTEM

NERVOUS SYTEM

Anatomical Classification Functional Classification



CNS PNS Afferent/ Efferent/

Sensory Motor

Brain SC SN CN

Somatomotor Autonomic

Cerebrum Diencephalon Brainstem Cerebellum

Sympa Parasympa

Thalamus Pineal Body Hypothalamus Medulla Oblongata

Pons

Midbrain

NEUROLOGICAL NURSING ASSESSMENT

1. Health History

ask the client about

headache;

clumsiness;

loss of or change in function of an extremity;

seizure activity;

numbness or tingling

change in vision;

pain;

extreme fatigue;

personality changes;

and mood swings.

2. Neurological Assessment



Involves assessment of LOC and verbal responses to specific questions; selected cranial nerves for

eye movement and visual acuity; muscle strength; movement; gait for motor function; and tactile and

pain sensation of extremities for sensory screening.

A complete nursing assessment of neurological function includes assessment of the following areas:

cerebral function, cranial nerve function, motor function, sensory function, and reflexes.

a. Cerebral function assessment includes:

a.1. Level of Consciousness is assessed by determining the clients awareness and orientation and is the

most important indicator of change in neurological status.

Consciousness Requires:

Arousal:

alertness; dependent upon reticular activating system (RAS); system of neurons in thalamus and upper

brain stem

Cognition:

complex process, involving all mental activities; controlled by cerebral hemispheres

Process that affect LOC:

Increased ICP

Stroke, hematoma, intracranial hemorrhage

Tumors

Infections

Demyelinating disorders

Systemic Conditions affecting LOC

Hypoglycemia

F/E imbalance

Accumulated waste products from liver or renal failure

Drugs affecting CNS: alcohol, analgesics, anesthetics

Seizure activity: exhausts energy metabolites



Level of Consciousness

Alert

Lethargic-very sleepy

Stuporous

Coma

Death

Awareness

is the persons ability to perceive stimuli and body reactions and then respond with thought and action.

The clients awareness is assessed through four (4) components: orientation, memory, calculation and

fund of knowledge.

Glasgow Coma Scale

an objective tool for assessing consciousness in clients, most frequently clients with head injuries.

GLASGOW COMA SCALE (?)

A score of 15 indicates a fully oriented person. A score of 3 indicates deep coma. A score of 7 is

considered a state of coma.

GLASGOW COMA SCALE

GLASGOW COMA SCALE

GLASGOW COMA SCALE

a.2. Orientation

is the persons awareness of self in relation to person, place and time.

-Using open-ended communication techniques, instruct the client to tell me your first and last name,

tell me the month, day, year and day of the week, tell me where you are.

a.3. Mental Status

requires observation of the clients appearance, behavior, posture, mood, gestures, movements, and

facial expressions.

The nurse compares these behaviors based on the clients age, health status, educational level and

social position. Mood is assessed by observing and asking the client about moods and feelings.



MENTAL STATUS ASSESSMENT WITH ABNORMAL FINDINGS

Unilateral neglect (lack of caring of the other side of the body); strokes involving middle cerebral artery

Poor hygiene and grooming: dementing disorders

Abnormal gait and posture: transient ischemic attacks(TIAs) , strokes, and Parkinsons disease

Emotional swings, personality changes: strokes

Aphasia-defective or absent language function: TIAs, strokes involving anterior/posterior artery; general

term for impairment of language

Dysphonia- change in tone of voice

Dysarthria- (different in speaking); is indistinctness of words in word articulation resulting from

interference with the peri pheral speech mechanisms (e.g. muscles of the tongue, palate, pharynx, or

lips) [Phipps, 1998, p. 1901]

Decreased level of consciousness

Confusion, Coma

a.4. Intellectual Function

is the ability of the brain to perform thought processes. Ability to concentrate, memory function (long

and short term memory), recall, calculation activities, and fund of knowledge.

a.5. Emotional Status

is assessed by observation of the clients affect (emotional response or mood).

Is affect appropriate for the situation?

Is affect labile (prone to rapid change)?

Is affect consistent with verbal communication

COGNITIVE FUNCTION ASSESSMENT WITH ABNORMAL FINDINGS

Disorientation to time and place: stroke of right cerebral hemisphere

Memory deficits

Emotional defense

a.6.Pupil reaction



size, equality, and roundness of pupils are assessed. Size is measured in millimeters. Pupils are

evaluated for symmetry of size and for reaction to light. Reaction is assessed as being brisk, sluggish, or

nonreactive; consensual reaction is also noted.

a.7.Communication

both written and oral communication are assessed.

Aphasia

inability to communicate verbally, can be caused by the inability to form words or the inability

to understand written or spoken word.

To assess communication function, ask the client to follow simple command such as Close your

eyes. During the health history, ask the client about health care expectations to evaluate the clients

ability for verbal expression. Have the client write his name and address on paper to evaluate the ability

to write.

b. Cranial Nerve Function

Cranial I (Olfactory):

-Anosmia

lesions of frontal lobes

impaired blood flow to middle cerebral artery.

Cranial II (Optic)

blindness in eye: strokes of internal carotid artery, TIAs

Homonymous hemianopia - impaired vision or blindness in one side of both eyes; blockage of posterior

cerebral artery.

Impaired vision: strokes of anterior cerebral artery; brain tumors

Note:

Visual acquity-mediated by the cones of the retina

Field of vision or peri pheral vision-portion of space in which objects are visible during the fixation of

vision in one direction. The receptors for peripheral fields are the rod neurons of the retina. (Phipps,

1998, p. 1906)



Cranial nerve III, IV, VI (Oculomotor, Trochlear, Abducens)-motor nerves that arise from the brainstem

Nystagmus - involuntary eye movement; strokes of anterior, inferior, superior, cerebellar arteries

Constricted pupils: may signify impaired blood flow to vertebralbasilar arteries.

� Ptosis (eyelid falldown); drooping of the upper eyelid over the globestrokes of

posterior inferior cerebellar artery; myasthenia gravis, palsy of CN III

Cranial nerve V (Trigeminal)largest cranial nerve with motor and sensory components

changes in facial sensations; impaired blood flow to carotid artery

Decreased sensation of face and cornea on same side of body; strokes of posterior inferior cerebral

artery

Lip and mouth numbness

Loss of facial sensation: contraction of masseter and temporal muscles, lesions CN V

Severe facial pain: trigeminal neuralgia (tic dorlourex)

Cranial VII (Facial nerve)mixed nerve concerned with facial movement and sensation of taste

1. Loss of ability to taste

2. Decreased movement of facial muscles

3. Inability to close eyes, flat nasolabial fold, paralysis of lower face, inability to wrinkle the forehead

4. Eyelid weakness; paralysis of lower face; paralysis of upper motor neuron

5. Pain, paralysis, sagging of facial muscles: affected side in Bells palsy

Cranial VIII (Acoustic)composed of a cochlear division related to hearing and a vestibular division

related to equilibrium (Phipps, 1998, p. 1909)

Decreased hearing or deafness: strokes of vertebralbasilar arteries or tumors of CN VIII

Cranial IX(Glossopharyngeal) and cranial X (Vagus)chief function of cranial nerve IX is sensory to the

pharynx and taste to the posterior third of tongue; cranial nerve X is the chief motor nerve to the soft

palatal, pharyngeal and laryngeal muscles (Phipps, 1998, p. 1909)



Dysphagia (difficulty swallowing)

Unilateral loss of gag reflex

Cranial XI (Spinal accessory)motor nerve that supplies the sternocleidomastoid muscle and upper part

of trapezius muscles

Muscle weakness

Contralateral hemiparesis: strokes affecting middle cerebral artery and internal artery

Cranial XII (Hypoglossal)

Atrophy, fasciculations (twitches): LMN disease

Tongue deviation toward involved side of the body

c. Motor Function

c.1. Muscle size and symmetry

are assessed by palpating major muscle groups of the arms and legs and then comparing them

to the muscle groups of the opposite side of the body.

Unilateral atrophy indicates a nervous system problem.

c.2. Muscle Tone assessed during palpation of major muscle groups for size and symmetry while at

rest and during passive movement.

Muscle tone is described as normal, flaccid, spastic, or rigid.

Flaccid muscles are hypotonic, or soft and flabby.

Spastic muscles are at first resistant to passive movement, but then release resistance.

Rigid muscles may have tremors but are constantly rigid. Rigidity is a more constant state of spasticity,

with fewer periods of release of resistance.

c.3. Muscle Strength

to assess, each extremity is placed through passive movement.

The client is then asked to move the extremity, first against gravity, by lifting the extremity off

the bed, then against the resistance.



5.Full power of contraction

4.Fair or moderate power of contraction

3.Just able to overcome force of gravity

2.Can move but cannot overcome power of gravity

1.Minimal contractile power

0.No movement

c.4. Coordination

is assessed by asking the client to perform repetitious movement. The client should close his

eyes and repeatedly, rapidly touch her own nose with alternate index fingers. Inability to perform this is

termed ataxia, incoordination of voluntary muscle action.

c.5. Balance

is evaluated by using the Rombergs Test. The client stands with the feet together; arms

extended in front and eyes closed.

c.6. Posturing

abnormal posturing occurs with injury to the motor tract.

Flexion posturing (formerly decorticate posturing) characterized by flexion of the arms, adduction

of the upper extremities, and extension of the lower extremities. Lesions of the cerebral hemispheres or

internal structures of the brain cause flexion posturing.

Extension posturing (formerly decerebrate posturing) is caused by brainstem injury and is

characterized by an arching of the back, backward flexion of the head, adduction and hyperpronation of

the arms, and extension of the feet. It represents greater dysfunction than does flexion posturing and

any change from flexion to extension posturing indicates a worsening condition

d. Sensory Function a subjective examination of sensory function, performed with the clients eyes

closed, is generally done only when a dysfunction is suspected.

d.1. Tactile Sensation

is tested by using a cotton ball to lightly touch the clients arms, hands, upper legs, and feet. Comparison

is done side to side. The client with eyes closed, indicated whether the cotton ball is felt.

d.2. Pain and temperature



sensation of pain and temperature are transmitted along the same pathways and are evaluated using a

sharp and dull touch. A paper clip or cotton-tipped applicator is used. The clients ability to distinguish

sharp and dull is noted, comparing both sides of the body.

d.3. Vibration

is tested using a tuning fork. Strike the tuning fork on the palm, holding only the handle, then

place the end of the handle first on the clients wrists and then on the ankles and ask whether the

vibrations are felt. The clients eyes should be closed during the test.

d.4.Proprioception is the sense of joint position in space. With the clients eyes remaining closed,

move a joint of the clients finger or extremity up or down in space and ask the client to distinguish the

direction of movement of the digit or extremity as being either up or down.

d.5.Steriognosis is the ability to recognize an object by feel. Place a familiar object such as a coin or

key in the clients hand and ask what the object is. This sensation is a function of the brain, not of the

spinal pathways.

d.6. Graphesthesia is the ability to identify letters, numbers, or shapes drawn on the skin.

d.7. Integration of sensation is a higher cortical function. A two-point discrimination test is performed

by touching the client simultaneously on opposite sides of the body with a sharp object and asking the

client to ascertain the number of objects felt. The normal response is two. If only one is felt, the brain

function of integration is abnormal.

e. Reflexes:

e.1. Deep tendon ref lexes (DTR) are involuntary contractions of muscles or muscle groups responding

to brisk stretching near the insertion site of muscle.

e.2. Superficial or cutaneous ref lexes are elicited by irritating the skin on the area being assessed.

They are diminished or absent with dysfunction of the reflex arc.

The superficial reflex generally assessed is the plantar. To assess the plantar reflex, the handle of the

reflex hammer is used to stroke the outer aspect of the sole of the foot from the heel and across the ball

of the foot to just below the big toe. Plantar flexion or curling under of the toes, should occur.

Abnormal reflexes- the absence of DTR in clients is considered an abnormal finding. A fanning of the

toes and dorsiflexion of the big toe in response to the assessment of the plantar reflex is calledBabinski Ref lex. This abnormal response indicates corticospinal disease and is the most important abnormal

superficial reflex.

Techniques Eliciting Major Reflexes

Figure Used to Record Muscle Strength

Gerontological Considerations



Important to distinguish normal aging changes from abnormal changes

Determine previous mental status for comparison. Assess mental status carefully to distinguish delirium

from dementia.

Normal changes may include:

Losses in strength and agility; changes in gait, posture and balance; slowed reaction times and

decreased reflexes; visual and hearing alterations; deceased sense of taste and smell; dulling of tactile

sensations; changes in the perception of pain; and decreased thermoregulatory ability

Diagnostic Tests

Computed tomography(CT)

Positron emission tomography (PET)

Single photon emission computed tomography (SPECT)

Magnetic resonance imaging (MRI)

Cerebral angiography

Myelography

Noninvasive carotid flow studies

Transcranial doppler

Electroencephalography (EEG)

Electromyography (EMG)

Nerve conduction studies, evoked potential studies

Lumbar puncture, Queckenstedts test, and analysis of cerebrospinal fluid

Magnetic Resonance Imaging

If you think education is expensive, try ignorance.

~Attributed to both Andy McIntyre and Derek Bok



Neuroglia-protect and nourish neurons; mitotic - do not transmit impulses

Neuroglia Function

A strocytes Supply nutrients to neurons

Microglia Provide protection against microorganisms

Oligodendrocytes Wrap tightly around nerve f ibers to f orm myelin sheath

Ependymal cells Ciliated; line brain cavities; f orms CSF

Schwann cells Phagocytic cells that f orm myelin sheath around nerve f ibe

Satellite cells Found in the PNS; may maintain chemical balance of neur

assessment of neurologic function

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