Neurological Assessment

There are many reasons and many ways to perform a neuro exam. Whether one of your Soldiers was hit by an explosion or experienced an emergency while diving, a thorough neurological assessment is indicated. At very least, a solid neuro exam will establish a baseline from which you can trend recovery. This post was based primarily on the U.S. Navy Dive Manual. You can find a link in the references. Please follow this post for updates and leave your suggestions and case studies in the comments.

Mental Status

General mental status is best determined when you first see the patient and is characterized by alertness, orientation, and thought process. Obtain a good history, the patient’s response to questioning during the neurological examination will give you a great deal of information about mental status.

“A & O x 4”

It is important to determine if the patient knows the time and place, and can recognize familiar people and understands what is happening. This would be considered alert and oriented to person, place, time, and event, or “A&Ox4”.

Glasgow Coma Scale (GCS)

The GCS gives medics a simple, reliable and standardized way to measure a patient’s best neurological response. The GCS is also a great tool because it is well correlated with outcomes from severe TBI. Calculating a GCS score doesn’t have to be a complicated process; an experienced medic can determine GCS in the course of a normal exam.

Use this scale to rate the best eye opening response, the best verbal response, and the best motor response your patient makes. The final GCS score is the sum of these numbers. Notice that the eye opening response is AVPU. It wouldn’t be a bad idea to print and laminate a GCS score card until it can be memorized.

Memory

Determine if the patient’s memory is intact by asking reasonable questions to which you know the answer. Try out the following questions:

• Who is your commander?
• What did you have for lunch?
• Where are you stationed?
• When did you last eat a meal?

Detailed Exam

If your patient gives you a strange response, or if you notice any abnormalities in their speech, you may choose to assess the patient’s cognitive function more fully. Cognitive function is an intellectual process by which one becomes aware of, perceives, or comprehends ideas and involves all aspects of perception, thinking, reasoning, and remembering. The Military Acute Concussion Exam (MACE) does an excellent job of assessing cognitive function. The Mini Mental State Exam (MMSE) also has useful elements for grading a patient’s cognitive function.

At a minimum, you should test the following:

Attention

• Ask the patient to spell “WORLD” backward.
• Ask the patient to count backward from 100 by sevens. Known as the “Serial Sevens Test”, this is to test the patient’s cognitive reasoning abilities, particularly their ability to concentrate and recall serial information.

Language

• Point to an object, such as your watch, and ask the patient “What is this called?”
• Write “You can’t teach an old dog new tricks” on a piece of paper and ask the patient to read it aloud.

Memory

• Ask the patient to repeat back and remember a series of words to be recalled later. The words should NOT sound alike or be too closely related. An example would be “Red Ball, Brown Dog, Blue Truck”.
• Ask the patient to recall the words from the beginning of the examination.

Coordination (Cerebellar / Inner Ear Function)

A good indicator of muscle strength and general coordination is to observe how the patient walks. A normal gait indicates that many muscle groups and general brain functions are normal.

If you notice an abnormal gait, a more thorough examination, testing the brain and inner ear, is indicated. In conducting these tests, both sides of the body should be tested and the results compared.

Heel-to-Toe Test

Also known as the “tandem walk”, the heel-to-toe test has been used as the standard “drunk driver” test. While looking straight ahead, the patient must walk a straight line, placing the heel of one foot directly in front of the toes of the opposite foot. Signs to look for and consider deficits include:

• Limping
• Staggering
• Falling to one side

Romberg Test with Pronator Drift

There are many different versions of the Romberg Test. Commonly, you will have the patient stand with eyes closed, feet together so that the heels touch, and arms extended to the front with palms up. Some examiners recommend starting with eyes open, tilting the head back during the test, or giving the patient a small shove from either side with the fingertips.

Signs to look for include:

Finger-to-Nose Test

The patient stands with eyes closed and head back, arms extended to the side. Bending the arm at the elbow, the patient touches his nose with an extended forefinger, alternating arms.

An extension of this test is to have the patient, with eyes open, alternately touch his nose with his fingertip and then touch the fingertip of the examiner. The examiner will change the position of his fingertip each time the patient touches his nose. In this version, speed is not important, but accuracy is.

Heel-Shin Slide Test

While standing, the patient touches the heel of one foot to the knee of the opposite leg, foot pointing forward. While maintaining this contact, he runs his heel down the shin to the ankle. Each leg should be tested. In the presence of limb ataxia it would be appropriate to have the patient sit.

Rapid Alternating Movement Test

The patient slaps one hand on the palm of the other, alternating palm up and then palm down. Any exercise requiring rapidly changing movement, however, will suffice. Again, both sides should be tested.

Motor

Extremity Strength

Muscle strength is graded on a scale of 0 to 5 with zero being completely paralyzed in the affected extremity.

1. Profound Weakness. Flicker or trace of muscle contraction.
2. Severe Weakness. Able to contract muscle but cannot move joint against gravity.
3. Moderate Weakness. Able to overcome the force of gravity but not the resistance of the examiner.
4. Mild Weakness. Able to resist a slight force of examiner.
5. Normal. Equal strength bilaterally (both sides) and able to resist examiner.

Both upper and lower extremities should be tested. Start by having the patient squeeze one or two of your fingers in their fists. Then, as you hold their feet, have the patient plantarflex “push me away” and dorsiflex “pull me toward you” against resistance.

Muscle Size, Tone, and Movement

Inspect the patient’s musculature for symmetry of posture and of muscle contours and outlines. Examine for fine muscle twitching. Look and feel for abnormalities in tone such as spasticity, rigidity, or no tone. Inspection may reveal slow, irregular, and jerky movements, rapid contractions, tics, or tremors.

Cranial Nerves

The cranial nerves are the 12 pairs of nerves emerging from the cranial cavity through various openings in the skull. Beginning with the most anterior (front) on the brain stem, they are appointed Roman numerals.

It is a daunting task for providers of all levels to memorize the cranial nerves and their functions. There are several nmemonics for remembering the nerves in order, some less appropriate for polite company.

The best way I have found to learn and retain this information is by drawing it out and by doing the assessments. The CN Face below is how I learned it in paramedic school and is still how I sometimes remind myself.

Many of the cranial nerves tests can be integrated into the course of a larger head to toe assessment. Challenge yourself to hit all of them during your assessment.

CN I Olfactory (Not Tested)

The olfactory nerve, which provides our sense of smell, is usually not tested in the field. Testing this nerve requires special equipment and perfumes. You may ask the patient if they’ve had any changes in their sense of smell if they present as a reliable historian.

CN II Optic

The optic nerve transmits signals from the eyes to the occipital lobe of the brain. It takes part in the recognition of light and shade and in the perception of objects. This test should be completed one eye at a time to determine whether the patient can read. Ask the patient if he has any blurring of vision, loss of vision, spots in the visual field, or peripheral vision loss (tunnel vision). More detailed testing can be done by standing in front of the patient and asking him to cover one eye and look straight at you. In a plane midway between yourself and the patient, slowly bring your fingertip in turn from above, below, to the right, and to the left of the direction of gaze until the patient can see it. Compare this with the earliest that you can see it with the equivalent eye. If a deficit is present, roughly map out the positions of the blind spots by passing the fingertip across the visual field. You may also elect to use a Snellen chart to test visual acuity.

CN III Oculomotor, IV Trochlear, VI Abducens

These three nerves control eye movements. All three nerves can be tested by having the patient’s eyes follow the examiner’s finger in all four directions (quadrants) and then in towards the tip of the nose (giving a “crossed-eyed” look). The oculomotor nerve can be further tested by shining a light into one eye at a time. In a normal response, the pupils of both eyes will constrict.

CN V Trigeminal

The Trigeminal Nerve governs sensation of the forehead and face and the clenching of the jaw. It also supplies the muscle of the ear (tensor tympani) necessary for normal hearing. Sensation is tested by lightly stroking the forehead, face, and jaw on each side with a finger or wisp of cotton wool.

CN VII Facial

The Facial Nerve controls the face muscles. It stimulates the scalp, forehead, eyelids, muscles of facial expression, cheeks, and jaw. It is tested by having the patient smile, show their teeth, whistle or puff out their cheeks, raise their eyebrows, and close their eyes tightly. The two sides should perform symmetrically. Symmetry of the nasolabial folds (lines from nose to outside corners of the mouth) should be observed.

CN VIII Acoustic

The Acoustic Nerve controls hearing and balance. Test this nerve by whispering to the patient, rubbing your fingers together next to the patient’s ears, or putting a tuning fork near the patient’s ears. Compare this against the other ear. Have the patient close their eyes and indicate with their hands which side they hear the sound.

CN IX Glossopharyngeal (Not Tested)

The Glossopharyngeal Nerves transmit sensation from the upper mouth and throat area. It supplies the sensory component of the gag reflex and constriction of the pharyngeal wall when saying “aah.” Test this nerve by touching the back of the patient’s throat with a tongue depressor. This should cause a gagging response. This nerve is normally not tested.

CN X Vagus

The Vagus Nerve has many functions, including control of the roof of the mouth and vocal cords. The examiner can test this nerve by having the patient say “aah” while watching for the palate to rise. Note the tone of the voice; hoarseness may also indicate vagus nerve involvement.

CN XI Spinal Accessory

The Spinal Accessory Nerve controls the turning of the head from side to side and shoulder shrug against resistance. Test this nerve by having the patient turn his head from side to side. Resistance can be provided by placing one hand against the side of the patient’s head but is not necessary. The examiner should note that an injury to the nerve on one side will cause an inability to turn the head to the opposite side or weakness/absence of the shoulder shrug on the affected side.

CN XII Hypoglossal

The Hypoglossal Nerve governs the muscle activity of the tongue. An injury to one of the hypoglossal nerves causes the tongue to twist to that side when stuck out of the mouth.

Sensory Function

Ask the patient whether they are experiencing any pain, numbness, or paresthesia “pins-and-needles”. If you feel it is necessary, you may test for sensory function. Sensations easily recognized by most normal people are sharp, dull, and light touch. It is possible to test pressure, temperature, and vibration in special cases.

An ideal instrument for testing changes in sensation is an object with a sharp and a dull end, such as a safety pin. You may also use a broken tongue depressor. Either of these objects must applied at intervals. Avoid scratching or penetrating the skin. It is not the intent of this test to cause pain. A piece of gauze may be used for light touch.

Using the dermatomes as a guide, alternate sensations and record whether the patient can discriminate between the instruments used. If an area of abnormality is found, mark the area as a reference point in assessment. Some examiners use a marking pen to trace the area of decreased or increased sensation on the patient’s body. During treatment, these areas are rechecked to determine whether the area is improving. An example of improvement is an area of numbness getting smaller

Deep Tendon Reflexes (DRT)

DRTs are not commonly tested in the field. The purpose of the deep tendon reflexes is to determine if the patient’s response is normal, nonexistent, hypoactive (deficient), or hyperactive (excessive). To get the best response, strike each tendon with an equal, light force, and with sharp, quick taps. Usually, if a deep tendon reflex is abnormal there will be other abnormal signs present.

Resources

1. U.S. Navy Dive Manual Appendix 5A Neurological Exam

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