Chapter 43

Assessment of the Nervous System

Mrs. Marion Kreisel MSN, RNNu230 Adult Health 2Fall 2011

Anatomy and Physiology

• Neurons: The basic unit of the NS, the neuron transmits impulses.

• Mechanism for nerve impulse conduction: Motor neurons for movement and sensory neurons for sensation

• Neuroglial cells: provide protection , structure & nutrion for the neurons

• ANS, sympathetic and parasympathetic

Anatomy and Physiology (Cont.)

Assessment

• Family history and genetic risk• Current health problems• Level of consciousness and orientation• Memory and attention• Language and higher levels of cognition

Assessment (Cont’d)

• Cranial nerves: KNOW CHART 43-4 on PAGE 935• Sensory function• Motor function• Cerebellar function

Assessment (Cont’d) • Reflex activity

Glasgow Coma Scale

A score of 15 is normal neurological functioning.A score of 7 represents a comatose state. The lower the score the lower the patients LOCIntubated patients and cannot talk get a “T” after the number. The highest they can score is an 11

Posturing DECORTICATE

DECEREBRATE

Laboratory Tests

• Blood cultures necessary• Skull and spine x-ray tests• Cerebral angiography• CT scan—possible use of contrast

medium, assess for allergic response, fluids

• MRI• Positron emission tomography• Single-photon emission CT• Magnetoencephalography (MEG)

Electroencephalography (EEG)

• Graphically records the electrical activity of the cerebral hemispheres

• Sleep deprivation requirement• Anticonvulsants possibly withheld

Evoked Potentials

• Measure the electrical signals to the brain generated by hearing, touch, or sight

• Auditory evoked potentials: assess high frequency hearing loss, damage to the acoustic nerve. Sound proof room, one ear at a time.

• Visual evoked potentials: detect loss of vision from optic nerve damage particularly in MS. On eye at a time and focus on a shifting checker board pattern

• Somatosensory evoked potentials: measure response from stimuli to the peripheral nerves. Detects nerve or spinal cord damage/degeneration esp. in MS. Tiny shocks to arm & leg

Cerebral Blood Flow Evaluation• Particularly useful in evaluating cerebral vasospasms• Use radioactive substances measure the uptake of it in an area.

Lumbar Puncture (Spinal Tap)

• Insertion of spinal needle into the subarachnoid space (between the third and fourth lumbar vertebrae)• CSF pressure readings• Check for blockage by SC lesion• Inject contrast for test• Inject medications• Rarely used to reduce some ICP

• Contraindicated in patients with increased intracranial pressure b/c sudden release of SF

• Empty bladder• Position• Spinal headache possible from spinal tap

Lumbar Puncture (Spinal Tap) continued

• Normal Pressure <20 mm H20• Normal Color: Clear• Normal Cells: 0-5 lymphocytes more than that

means infection!• Normal Protein: 15-45 mg/dl. High means

infection!• Normal Glucose: 50-75mg/dl

•KNOW THIS SLIDE!

Cerebrospinal Fluid

Other Studies

• Transcranial Doppler ultrasonography: Uses sound waves to measure blood flow through the arteries.

• Muscle and nerve biopsy: used to DX neuromuscular disorders.

NCLEX TIME

Question 1

The nurse can best assess the patient’s cognition by:

A. Asking the patient about how he was transported to the clinic

B. Asking the patient about the meaning of various proverbs

C. Asking the patient to count backward from 100 by 7s

D. Writing down a simple command and giving it to the patient

Question 2

The most common cause responsible for changes in an older patient’s mental state is:

A. Changes in extracellular electrolytesB. Insufficient oxygenC. Sedative agentsD. Changes in acetylcholine levels

Question 3

Approximately how much cerebrospinal fluid (CSF) is produced daily by the choroid plexus?

A. <100 ml B. 125 ml to 150 ml C. 200 ml to 300 mlD. 500 ml

Question 4

The nurse provided colostomy care instruction to an older adult yesterday. Today, the nurse observes that the patient is not applying the colostomy collection device correctly. The nurse should:

A. Request the patient’s daughter learn how to care for the patient’s colostomy.

B. Re-instruct the patient on the care of the colostomy.C. Offer to complete the colostomy care for the patient.D. Ask the patient what he remembers about the

colostomy care instruction he received the day prior.

Question 5

Which assessment variable is the best indicator of a change in a patient’s neurologic status?

A. Alert and oriented to place, person, timeB. Alert but not oriented to place, person, or

time C. Lethargic but arousable D. Deep stimulation needed to arouse patient