Assessment and Observation of the Neurologic System

Learning objectives for this chapter

By the end of this chapter, we would like you:

-To describe the basic anatomy and physiology of the neurologic system.

-To explain how to collect a focused health history related to the neurologic system.

-To explain how to undertake a physical examination of the neurologic system.

-To discuss the age-related differences to be considered when assessing the neurologic system.

-To explain how to document neurologic system assessment findings.

-To recognise the common neurologic problems / conditions, and their typical clinical presentation, to enable differential diagnosis

-To describe the variety of special assessment techniques which may be used in the physical examination of the neurologic system.

Fundamental anatomy and physiology of the neurologic system

The neurologic system, comprised of the nervous systems, controls: (1) all the body’s functions, and (2) responses, both automatic and voluntary, to external and internal stimuli. There are three divisions of the neurologic system:

• The central nervous system, comprised of the brain, spinal cord and protective structures.
• The peripheral nervous system; a system of nerves which regulates the body’s response to external stimuli. The peripheral nervous system is comprised of twelve pairs of cranial nerves and thirty-one pairs of spinal nerves, each controlling a different part of the body. Review the following information about these nerves:

Cranial Nerve Number	Name	Function
I	Olfactory	Reception and interpretation of smell.
II	Optic	Visual acuity.
III	Oculomotor	Raise / lower eyelids; most extraocular movements; pupillary constriction; change lens shape.
IV	Trochlear	Downward, inward eye movements.
V	Trigeminal	Jaw opening, closing, clenching movements; sensation to eyes, eyelids, forehead, nose, mouth, teeth, tongue, facial skin, etc.
VI	Abducens	Lateral eye movement.
VII	Facial	Most facial expressions; some speech sounds; reception and interpretation of taste; secretion of saliva / tears.
VIII	Acoustic	Reception and interpretation of sound; equilibrium.
IX	Glossopharyngeal	Voluntary swallowing; some speech sounds; gag reflex; taste (posterior one-third of tongue); secretion of saliva.
X	Vagus	Swallowing; some speech sounds; sensation to parts of the ear; secretion of digestive enzymes; carotid reflex; involuntary action of the heart / lungs / digestive tract.
XI	Spinal accessory	Turn head; shrug shoulders; some speech sounds.
XII	Hypoglossal	Tongue movement; some speech sounds; swallowing.

• The autonomic nervous system; another system of nerves which regulates the body’s internal environment.

Neurologic system – focused health history

When assessing a patient’s neurologic system, the nurse must commence by collecting a health history. This involves collecting data about:

• Present health status.
  • Changes the client / significant others have noticed in their ability to move.
  • Chronic diseases.
  • Current medications.
  • Alcohol consumption.
• Past medical history.
  • Injuries to the head / brain, spinal cord and / or nerves.
  • Surgery on the head / brain, spinal cord and / or nerves.
  • History of stroke or seizure disorder.
• Family history of neurologic conditions.

In some cases, a person will present with a specific problem related to their neurologic system.

Neurologic system – physical examination

A nurse may commence a physical examination of the patient’s neurologic system:

• Assess the person’s mental status and level of consciousness. This is a subjective judgement a nurse makes whilst collecting a health history from the person.
• Assess the person’s speech for articulation, voice quality and comprehension of verbal communication.
• Assess the functioning of each of the cranial nerves by:
  • CNI: asking the client about their sense of smell.
  • CNII: asking a client about their sense of sight.
  • CNIII, CNIV and CNVI: observing the client’s eye movements.
  • CNV: observing the blinking of the client’s eyes.
  • CNVII: observing the symmetry of the client’s facial movements.
  • CNVII: asking the client about their sense of hearing.
  • CNIX and CNS: observing the client’s ability to swallow saliva.
  • CNX: listening to the client’s guttural speech sounds.
  • CNXI: observe the patient’s capacity to turn their heads, shrug their shoulders, etc.
  • CNXI: observe the client’s ability to pronounce words.
• Assess the peripheral nerves.
• Assess the client’s gait for balance and symmetry.
• Evaluate the client’s extremities for strength.
• Assess the client’s cerebellar function for balance and coordination.
• Assess the client’s deep tendon reflexes.
• Assess the client’s level of consciousness. A simple mnemonic – ‘AVPU’ – is used to prompt nurses during this step:
  • The patient is alert.
  • The patient responds to voice.
  • The patient responds to pain.
  • The patient is unresponsive.
• Assess the client’s pupils for their size, shape, equality and response to light.

Special assessment techniques for the neurologic system

In some cases, when performing a physical examination of the neurologic system, a nurse may identify the need to test the function of one or more of the cranial nerves. This is done following:

• CNI (olfactory nerve): the nurse should ask the client to close their eyes, occlude one nostril, and then ask a client to identify a common aromatic substance held under their nose.
• CNII (optic nerve): the client should be referred to an ophthalmologist or optometrist for an evaluation of their visual acuity.
• CNIII (oculomotor nerve), CNIV (trochlear nerve) and CNVI (abducens nerve): the client should be asked to move their eyes left-right, up-down and obliquely.
• CNV (trigeminal nerve): the patient should be asked to clench their teeth, and the nurse palpates the temporal and master muscles for mass and strength. The nurse should then ask the patient to close their eyes and lightly touch the patient’s forehead, nose and jaw, ensuring the client can feel sensation equally over these areas.
• CNVII (acoustic nerve): the client should be referred to an otologist for an evaluation of their hearing.
• CNIX (glossopharyngeal nerve): the nurse should apply small quantities of salt, sugar and lemon to the client’s anterior and posterior tongue, and ensure the client can differentiate between the salty, sweet and bitter tastes.
• CNX (vagus nerve): the nurse should ask the client to open their mouth and say ‘ah’, and observe the movement of their soft palate and uvula.
• CNXI (spinal accessory nerve): the patient should be asked to shrug their shoulders upwards against the nurse’s hands, with the nurse observing for strong and symmetric contraction of the trapezius muscles.
• CNXII (hypoglossal nerve):  the nurse should ask the client to protrude their tongue, and move it left-right and up-down.

In addition to evaluating the cranial nerves, it is important that the nurse assesses the peripheral nerves. This is done by:

• Asking the client to close their eyes, and using a cotton ball to apply superficial light touch to an area of the client’s extremities. The client should be able to determine the location and type of touch.
• Asking the client to close their eyes, and using a moderately sharp object to touch to an area of the client’s extremities. The client should be able to determine the location and type of touch.
• Asking the client to close their eyes, and using a vibrating object to touch to an area of the client’s extremities. The client should be able to determine the location and type of touch.
• Asking the client to close their eyes, before grasping one of the client’s finger / toe and moving it upwards or downwards. The client should be able to determine: (1) which toe was moved, and (2) the direction in which it was moved.

It is necessary that a nurse assess a client’s cerebellar function for balance and coordination. This can be done in a variety of different ways – for example:

• Romberg’s test: the client should be asked to stand with their feet together, arms resting at their sides and their eyes closed. The client may sway slightly, but their foot position and upright posture should be maintained.
• The client should be asked to stand on one foot, and then on the other; they should be able to maintain each position for at least 5 seconds. The client should then be asked to hop from one foot to the other.
• The client should be asked to walk heel-to-toe; they should be able to walk in this way in a straight line for some distance.
• The client should be asked to hold their arms out in front of their body, and perform several knee-bends; they should have sufficient muscle strength, coordination and balance to accomplish this task.
• The client should be asked to walk on their toes, and then on their heels; the client should be able to walk several steps on both their toes and their heels.
• The client should be asked to sit, place their hands on their knees, and rapidly move their hands so their palms are alternately up and down; the client should be able to maintain a rapid pace with good coordination throughout this activity.
• The client should be asked to sit, close their eyes, and use each index finger to rapidly touch their nose. The client should then be asked to open their eyes and move their finger rapidly between the nurse’s finger, held at a distance of approximately 50 centimetres from the client’s face, and the client’s own nose. The client should be able to touch their nose in a rhythmic pattern.
• The client should be asked to touch each finger on their hand to their thumb, in rapid sequence; the client should be able to perform this activity using a rhythmic pattern.

Also, it is important that a client’s deep tendon reflexes are assessed. This is done as follows:

• To assess the triceps reflex, a nurse should grasp a patient’s arm with the elbow flexed at a 90 angle. The triceps tendon – located just above the elbow, at the back of the arm – should be struck with a reflex hammer. The nurse should observe contraction of the triceps tendon with extension of the elbow.
• To assess the biceps reflex, a nurse should grasp a patient’s arm with the elbow flexed at a 90 angle. The biceps tendon – located just above the elbow, on the inside of the arm – should be struck with a reflex hammer. The nurse should observe contraction of the biceps tendon with flexion of the elbow.
• To assess the patellar reflex, a nurse should position a patient so they are sitting with their legs hanging freely at a 90 angle. The patellar tendon – located just below the patellar, or kneecap – should be struck with a reflex hammer. The nurse should observe contraction of the patellar tendon with extension of the knee.
• To assess the Achilles tendon, a nurse should position a patient so they are sitting with their legs hanging freely at a 90 angle. The Achilles tendon – located at the back of the ankle – should be struck with a reflex hammer. The nurse should observe contraction of the gastrocnemius muscle with plantar flexion of the foot.

The deep tendon reflexes are scored as follows:

Score	Response
0	No response.
1+	Sluggish or diminished response.
2+	Expected active, brisk response.
3+	Slightly hyperactive response.
4+	Hyperactive response with clonus.

Differential diagnosis in the neurologic system

When assessing a patient’s neurologic system, there are a number of common problems and conditions a nurse may identify:

• Multiple sclerosis – an autoimmune condition involving progressive demyelination of nerves in the central nervous system.
• Meningitis – an infection of the tissues surrounding the brain and / or the spinal cord.
• Encephalitis – an infection of the tissues surrounding the brain and / or the spinal cord AND the brain / spinal cord.
• Spinal cord injury.
• Brain injury.
• Parkinson’s disease – a condition involving the degradation of the dopamine-producing neurons in the brain.
• Stroke – which may be ischaemic or haemorrhagic.
• Alzheimer’s disease – a neurologic disorder due to degradation of the brain tissue.
• Trigeminal neuralgia – a condition involving dysfunction in the trigeminal nerve.
• Myasthenia gravis – an autoimmune condition involving destruction of the acetylcholine receptor sites.
• Guillain-Barre syndrome – a condition caused by the widespread demyelination of nerves in the central nervous system.

Conclusion

It is important that nurses are able to accurately and comprehensively assess this system, and this chapter has introduced the fundamental knowledge and skills nurses require to do so. It began with an overview of the fundamental anatomy and physiology of the neurologic system. The chapter then explained the processes involved in collecting a general health history for the neurologic system, and in performing a physical examination of the neurologic system. Finally, this chapter considered a number of special observation and assessment techniques which may be used in the physical examination of the respiratory system, and it discussed performing differential diagnosis relevant to the neurologic system.