Physical Assessment - Chapter 8 Neurological System
Chapter 8: Neurological System
The nervous system consists of the central nervous system (CNS), the peripheral nervous system, and the autonomic nervous system. Together these three components integrate all physical, emotional, and intellectual activities. The CNS includes the brain and spinal cord. These two structures collect and interpret voluntary and involuntary sensory and motor signals. A brief overview of the anatomy and physiology of the CNS is provided.
: The brain collects, integrates, and interprets all stimuli. It also initiates voluntary and involuntary motor activity. The brain is composed of three areas: the cerebrum, brain stem, and cerebellum.
: Divided into right and left hemispheres. Each hemisphere has four lobes: parietal, occipital, temporal, and frontal. The cerebral lobes control complex problem-solving; value judgements; language; emotions; interpretation of visual images; and interpretation of touch, pressure, temperature, and position sense.
: Composed of the midbrain, pons, and medulla. Is a major sensory and motor pathway for impulses running to and from the cerebrum. Regulates body functions such as respiration, auditory and visual reflexes, swallowing, and coughing.
: Lies in the posterior portion of the skull and contains the major motor and sensory pathways. It controls smooth, coordinated muscle movements and helps to maintain equilibrium.
: The spinal cord is the primary pathway for messages traveling between the peripheral areas of the body and the brain. It also houses the reflex arc for actions such as the knee-jerk reflex.
The manner in which you progress with your neurological assessment depends upon the patient’s level of consciousness. To perform a complete neurological exam on the patient, he/she must be able to cooperate.
Health History Assessment
A neurological health history can be obtained if the patient is alert enough and oriented to person, place, and time. If the person appears to be disoriented or confused upon questioning, ask family members and friends to confirm the information.
The person should be questioned as to previous history of seizures, loss of consciousness, anesthesia (an absence of normal sensation – especially to pain), paresthesia (numbness and tingling; a “pins and needles” feeling), neuralgia, twitches, tremors, personality changes, memory deficits, mental deterioration, nervousness, anxiety, history of psychiatric problems, vertigo, sensory disturbance, phobias, hallucinations, delusions, illusions, nightmares, insomnia, and/or grandiose ideas.
Differences Among Hallucinations, Delusions, and Illusions
: A sensory perception not resulting from external stimuli. An example would be someone who is hearing voices.
: A persistent belief even though illogical. An example would be someone who is feeling controlled by external sources.
: A false interpretation of external stimuli. Examples of illusions inlcude seeing mirages or hearing the ocean in a sea shell.
A complete neurologic assessment consists of five steps: o Mental status exam o Cranial nerve assessment o Reflex testing o Motor system assessment o Sensory system assessment
Mental Status Exam
The mental status exam really assesses the patient’s cerebral function. Remember that the cerebrum controls sophisticated mental functions such as speech, problem solving, and memory. As you perform this portion of the neurological assessment, pay special attention to the patient’s speech and language abilities. His speech should be clear, coherent, and spoken at an appropriate rate. The language used should be appropriate for the education and socioeconomic levels of the person. Altered speech patterns can alert you to the possibility of neurologic problems.
: (Memory, Orientation, Recognition, Calculations)
: Assess time, place, person. Organic brain disorders lose time first, then place, rarely person.
: Should be able to focus on examiner’s questions and respond. Impaired in anxiety, fatigue, intoxication.
: Ask for 24 hour diet recall and other easily verifiable information. Impaired in organic brain syndromes and Alzheimer’s.
: Ask for past health, birthdays, anniversary, relevant history. Lost in Alzheimer’s, cortical injury, but not in normal aging or most organic brain syndromes.
: Assess 4-word recall (should be able to recall all four at 10 minutes and three words at 30 minutes). Use the word groups “brown, honesty, tulip, eyedropper” or “fun, carrot, ankle, loyalty”. Four-word recall is impaired in Alzheimer’s, anxiety, and depression.
: Ask questions such as “What would you do if your house caught fire?” or “What are your plans for the future?”. Judgement is impaired in mental retardation, emotional dysfunction, schizophrenia, and organic brain disease.
: Visual hallucinations are often associated with medications and organic syndromes. Auditory hallucinations are associated more with psychiatric disorders.
Cranial Nerve Assessment
The following guide will provide a quick overview of each cranial nerve’s function.
Cranial Nerve Assessment Techniques
Cranial Nerve I (Olfactory)
After assessing patency of both nares, have client close eyes, obstruct one nare, and sniff. Use common, easily identifiable substances such as coffee, toothpaste, orange, vanilla, soap, or peppermint. Use different substances for each side. Bilateral decreased sense of smell occurs with age, tobacco smoking, allergic rhinitis, cocaine use. Unilateral loss of sense of smell (neurologic anosmia) can indicate a frontal lobe lesion.
Cranial Nerve II (Optic)
Check visual acuity (have the patient read newspaper print) and visual fields for each eye. Unilateral blindness can indicate a lesion or pressure in the globe or optic nerve. Loss of the same half of the visual field in both eyes (homonymous hemianopsia) can indicate a lesion of the opposite side optic tract as in a CVA.
Cranial Nerve III (Oculomotor)
Assess pupil size and light reflex. A unilaterally dilated pupil with unilateral absent light reflex and/or if the eye will not turn upwards could indicate an internal carotid aneurysm or uncal herniation with increased intracranial pressure.
Cranial Nerve IV (Trochlear) and Cranial Nerve VI (Abducens)
Have patient turn eyes downward, temporally, and nasally. If the eyes will not do this the patient may have a fracture of the eye orbit or a brain stem tumor. (Note: Cranial Nerves III, IV, and VI are examined together because they control eyelid elevation, eye movement, and pupillary constriction.)
Cranial Nerve V (Trigeminal)
Motor – Palpate jaws and temples while patient clenches teeth.
Sensory – Have patient close eyes, touch cotton ball to all areas of face.
Unilateral deficit seen with trauma and tumors.
Cranial Nerve VII (Facial)
Check symmetry and mobility of face by having patient frown, close eyes, lift eyebrows, and puff cheeks.
Sensory Asses the patient’s ability to identify taste (sugar, salt, lemon juice)
An asymmetrical deficit can be found in trauma, Bell’s palsy, CVA, tumor, and inflammation.
Cranial Nerve VIII (Acoustic or Vestibulocochlear)
This tests hearing acuity. Impairment indicates inflammation or occlusion of the ear canal, drug toxicity, or a possible tumor.
Cranial Nerve IX (Glossopharyngeal) and X (Vagus)
Depress the tongue with a tongue blade and have the patient say “ahh” or yawn. Uvula and soft palate should rise. Gag reflex should be present and the voice should sound smooth.
Deficits can indicate a brain stem tumor or neck injury.
Cranial Nerve XI (Spinal Accessory)
Have the patient rotate the head and shrug shoulders against resistance. If the patient is unable to do this it may indicate a neck injury.
Cranial Nerve XII (Hypoglossal)
Assess tongue control.
Wasting of the tongue, deviation to one side, tremors, and an inability to distinctly say l,t,d,n sounds can indicate a lower or upper motor neuron lesion.
When you strike a slightly stretched tendon with a reflex hammer, a simple muscle contraction occurs. What kind of information do deep tendon reflexes (DTRs) give the examiner? DTRs assist with evaluation of lower motor neurons and fibers. For example, if the patient’s biceps reflex is normal, you know that the lower motor neurons and fibers at levels C5 and C6 are intact.
There are five reflexes to check which include:
: With the patient sitting, flex his arm at the elbow and rest his forearm on his thigh with the palm up. Place your thumb firmly on the biceps tendon in the antecubital fossa. Strike your thumb with the hammer. The elbow and forearm should flex, and the biceps muscle should contract.
: The triceps tendon is tested with the patient’s arm flexed at a 90° angle. Supporting the arm with your hand, strike the triceps tendon on the posterior arm just above the elbow. The tendon should contract and the elbow extend.
: Have the patient rest his slightly flexed arm on his lap with the palm facing downward. Strike the posterior arm about two inches above the wrist on the thumb side. The forearm should rotate laterally and the palm turn upward.
: Dangle the patient’s legs over the side of the bed. Place your hand on the patient’s thigh and strike the distal patellar tendon just below the kneecap. (If the patient must remain supine, flex each leg to a 45° angle and place your dominant hand behind his knee to support it.) The normal response is contraction of the quadriceps muscle with extension of the knee.
: Have the patient dorsiflex (point downward) his foot slightly and lightly tap the Achilles’s tendon on the posterior ankle area. A slight jerking of the foot should be seen.
To assess deep tendon reflexes:
- Encourage the patient to relax the arm or leg being tested.
- Position the arm or leg so the appropriate tendon is slightly stretched.
- Hold the reflex hammer lightly and swing it freely in an arc.
- Strike the tendon with a brisk downward stroke, then lift up on the hammer immediately. When learning to perform DTRs, many people either tap too lightly or they strike firmly but leave the hammer on the tendon which reduces the response.
- Be sure to compare responses from one side to the other.
- Grade the reflexes in the following manner:
4+; Hyperactive; Often pathologic; may be associated with disease of the cerebral cortex, brain stem, and spinal cord. 3+; Brisker than normal; Not necessarily pathologic. 2+; Normal 1+; Diminished; May be normal 0; Absent; Pathologic; associated with both upper and lower motor neuron disease or injury.
A patient with multiple sclerosis might have hyperactive reflexes, while areflexia (absence of reflexes) can appear in Guillain-Barr? syndrome. Depressed or hyperactive reflexes can also signal an electrolyte imbalance.
Motor System Assessment
Assessment of the motor system includes evaluation of bilateral muscle strength and coordination and balance tests. Be sure to assess bilaterally and compare findings.
Examine the arm and leg muscles looking for atrophy and abnormal movements such as tremors. For a quick check of muscle tone, perform passive range of motion exercises and note any resistance. Next, instruct the patient to bend the forearm up at the elbow (flexion) while you hold the patient’s wrist exerting a slight downward pressure. This tests the strength of the biceps. Then test the triceps by having the patient extend his arm while you push against his wrist. Hand grasps should also be assessed. Ensure that the patient follows instructions to release the hand when assessing grip strength. In some cases, gripping the examiner’s hands is almost reflex while being able to release the hand grasp on command is more important.
Assess upper leg muscle strength of a bed patient by having him flex his hip and knee so that the knee is about 8 inches off the bed. Tell the patient to maintain this position while you attempt to push down against the thigh. Standing at the foot of the bed, test lower leg and foot muscle strength by having the patient push his foot against your hand, then have him pull it up against your hand.
Coordination and Balance Tests
Coordination can be checked by having the patient close the eyes and touch the finger to the nose. Coordination can also be assessed by having the patient perform rapid alternating movements (RAMs). The patient is instructed to pat his upper thigh with the same side hand, alternately patting with the palm and the back of the hand as quickly as possible. Repeat with both hands. These tests will help you evaluate coordination and detect intentional tremors.
If your patient is confined to bed, you won’t be able to test his balance. However, if he can stand beside the bed, you can perform the Romberg test for balance. With the feet together and arms to the sides as if standing at attention, have the patient maintain this position for about 30 seconds with the eyes open then another 30 seconds with his eyes closed. Stay close to the patient in case he starts to fall. It is normal to see minimal swaying. In some illnesses, vision compensates for a sensory loss. If the patient has a cerebellar disease, he may be able to maintain his balance with the eyes open, but not with them closed.
Sensory System Assessment
Follow these steps when testing the patient’s sensory system:
o Instruct the patient to keep his eyes closed during all the tests. o Compare one side with the other, noting whether sensory perception is bilateral. o If you detect an area of increase or decreased sensation, mark it with a water-soluble marker and note which peripheral nerves carry sensation to the area.
The assessment of the sensory system includes the evaluation of Cranial Nerve V, the trigeminal nerve (see facial evaluation). You will also be testing the patient’s ability to detect superficial pain. If the pain sensation is present, you do not have to test for temperature. To test for pain, have the patient close his eyes and let you know when you are touching a sterile needle to his skin. Lightly touch the proximal and distal aspects of the arms and legs with the needle.
Age Related Changes of the Neurological System
Decreased sensitivity to outside stimuli slows response time. Older people may not realize the air temperature is too cold or too warm. Vision is affected by aging as the lens of the eye begins to stiffen and lose water, compromising its ability to change shape for focus. Pupils become smaller, decreasing the amount of light reaching the retina, so an older person may find it hard to see in dim light. Hearing decreases because of natural or mechanical means. By the time a person reaches age 80, brain weight may be as much as 10% less than it was, blood flow to the brain decreases, and brain metabolism slows.