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I. Overview of the Neurological System

The assessment of the neurological system include examinations of mental status, level of consciousness and examinations of the neurological function. While details of the mental status assessment will be described in the next chapter, this chapter will begin with a review of the 12 pairs of cranial nerves and their functions. It will follow by a collection of some important terminologies of this system, and then continue with key assessment components for the system.

II. Anatomy and Physiology

Click the link below to review anatomy and physiology of the neurological system. In the assessment process, you will need to apply your knowledge of the 12 pairs of cranial nerves and their functions to the neurological system.

III. Medical Terminology

The following are commonly used medical terminologies in the assessment of neurological system.

IV. Step by Step Assessment

• Perform hand hygiene.
• Check room for contact precautions.
• Introduce yourself to patient.
• Confirm patient ID using two patient identifiers (e.g., name and date of birth).
• Explain process to patient.
• Assemble equipment prior to starting exam.
• Be organized and systematic in your assessment.
• Use appropriate listening and questioning skills.
• Listen and attend to patient cues.
• Ensure patient’s privacy and dignity.
• Apply principles of asepsis and safety.
• Check vital signs.

Steps	Additional Information
Obtain the health history related to mental status and the neurological system. Assess mental health status, alertness and orientation, level of consciousness (LOC) general appearance, and behavior. Observe the patient’s appearance, attitude, activity (behavior), mood/affect. Note hygiene, grooming, speech patterns, and facial expressions. Observe gait and balance.	Ask relevant questions related to past or recent history of head injury, neurological illness, or symptoms, confusion, headache, vertigo, seizures, recent injury or fall, weakness, numbness, tingling, difficulty swallowing (dysphagia) or speaking (dysphasia), and lack of coordination of body movements.
3. Assess 12 cranial nerve functions. (See chart below for more details).	CNI – Assess smell CNII- Assess visual acuity by using Snellen chart. Normal vision is 20/20. The top number indicates the distance of the patient can see, and the bottom number indicates what a person with normal vision can see. Assess peripheral vision: Ask the patient to cover one eye and the examiner cover the opposite eye. The examiner will move hand/fingers near the visual field. The patient and the examiner should see hand/fingers at the same time. CNIII/IV/VI – assess extraocular eye movements with 6 cardinal directions of gaze. Ask the patient to keep the head still and only move eyes. Follow the examiner’s finger or an object to move in 6 directions. CN III -pupillary reaction – assessing pupils for size, shape, and reaction to light: Pupils Equal Round, Reactive to Light, and Accommodation (PERRLA) Normal pupillary reflexes include direct reflex and consensual reflex. CN V – assess jaw clench and sharp/dull sensation over three branches (forehead, cheek, and chin) bilaterally. CN VII – ask the patient to raise eyebrows, smile, puff out cheeks, show teeth, squeeze eyes shut. CN VIII – assess hearing by whispering or by lightly rubbing the examiner’s fingers next to ear. CN IX /CN X – assess swallow, and check movement of soft palate and gag reflex. CN XI – assess motor function of the spinal accessory nerve by asking the patient to shrug shoulders while the examiner applies pressure. Trapezius muscles should be strong and symmetric. CN XII – assessing tongue movement
4. Assess motor strength and sensation. Check arms and legs for strength and compare bilaterally. Assess strength in the upper extremities by asking the patient to squeeze hands. Assess strength in the lower extremities by asking the patient to raise legs against the examiner’s hands; the examiner places both hands on the patient’s inner thighs and asks the patient to bring legs together; the examiner places both hands on the outer thighs and asks the patient to move legs apart; the examiner places hands on the back of the patient’s feet and asks the patient to perform dorsiflexion; the examiner places hands at the bottom of the patient’s feet and asks the patient to press down. Assess extremities for sensation, numbness, tingling.	Unequal motor strength and unusual sensation may indicate underlying neurological disease or injury, such as stroke or head injury. Expected findings should be equal strength bilaterally, no pain/numbness/tingling sensation.
5. Report and document assessment findings and related health problems according to agency policy.	Accurate and timely documentation and reporting promote patient safety.

Assess 12 Cranial Nerve Functions

Click all hyperlinks to access more details.

Mnemonic	#	Name	Function (Sensory/Motor/Both)	Assessment
On	I	Olfactory	Smell (S)
Old	II	Optic	Vision (S)	Visual acuity  Visual field
Olympus’	III	Oculomotor	Eye movements (M)	Pupillary reaction and Accommodation  Eye movements (CN III, IV, VI)
Towering	IV	Trochlear	Eye movements (M)
Tops	V	Trigeminal	Sensory/motor – face (B)	Facial movement and sensation
A	VI	Abducens	Eye movements (M)
Finn	VII	Facial	Motor – face, taste (B)	Facial motor function
And	VIII	Auditory (Vestibulocochlear)	Hearing/balance (S)	Hearing
German	IX	Glossopharyngeal	Motor – throat, taste (B)	Movement of the soft palate and gag reflex (CNIX and X)
Viewed	X	Vagus	Motor/sensory – viscera (autonomic) (B)
Some	XI	Spinal Accessory	Motor – head and neck (M)	Shrug shoulder
Hops	XII	Hypoglossal	Motor – lower throat (M)	Tongue

^{Copyrighted materials used with permission of the author, A. Chandrasekhar, Loyola University Medical Education Network.}

^{Table adapted from Biga et al. Anatomy & Physiology. https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/}

 V. Documentation

VI. Related Laboratory and Diagnostic Procedures/Findings

Depending on the patient’s signs and symptoms from physical examination, some diagnostic tests could be performed. For example, lumbar puncture (spinal tap) is to collect a sample of the patient’s spinal fluids to check if the patient has an infection in the brain or spinal cord or cancer in the brain. Imaging study such as magnetic resonance imaging (MRI) or computed tomography (CT) scan to diagnose a specific neurological disorder. Electroencephalogram (EEG) measures electrical activity in the brain that can be used to diagnose seizures, psychiatric disorders and other conditions of the brain.

VII. Learning Exercise

VIII. Attributions and References

• Biga, L. M., Dawson, S., Harwell, A., Hopkins, R., Kaufmann, J., LeMaster, M., Matern, P., Morrison-Graham, K., Quick, D., & Runyeon, J. Anatomy & Physiology.  http://library.open.oregonstate.edu/aandp/chapter/13-3-spinal-and-cranial-nerves/#tbl-ch13_03
• Chandrasekhar, A. (March 28, 2006 updated). Screening Physical Exam. http://www.meddean.luc.edu/lumen/MedEd/medicine/pulmonar/pd/contents.htm
• Doyle, G. R. & McCutcheon, J. A. Clinical Procedure for Safer Patient Care. https://opentextbc.ca/clinicalskills/chapter/2-5-focussed-respiratory-assessment/
• Hacking, C. & Gaillard, F. Radiopaedia.org. https://radiopaedia.org/articles/olfactory-nerve?lang=us. Accessed July 20, 2019.
• Michael Gibson, C.,  Bahekar, P., & Sharfaei, S. WikiDoc: Glasgow coma scale. https://www.wikidoc.org/index.php/Glasgow_coma_scale. Accessed July 20, 2019.
• National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Neurological-Diagnostic-Tests-and-Procedures-Fact. Accessed July 20, 2019.
• Orlando, G. (2006). Animation that illustrates the pupillary light reflex. Public domain via Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Eye_dilate.gif
• Psychology Wiki https://psychology.wikia.org/wiki/Level_of_consciousness. Accessed 7/16/2021