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Open Resources for Nursing (Open RN); Ernstmeyer K, Christman E, editors. Nursing Skills [Internet]. Eau Claire (WI): Chippewa Valley Technical College; 2021.
Perform a neurological assessment, including mental status, cranial nerves, sensory function, motor strength, cerebellar function, and reflexes
Modify assessment techniques to reflect variations across the life span Document actions and observations Recognize and report significant deviations from normsThe neurological system is a complex and intricate system that affects all body functions. A neurological assessment includes collecting subjective and objective data through an interview and detailed physical examination of the central nervous system and the peripheral nervous system. Let’s begin by reviewing the anatomy of the neurological system.
When completing a neurological assessment, it is important to understand the functions performed by different parts of the nervous system while analyzing findings. For example, damage to specific areas of the brain, such as that caused by a head injury or cerebrovascular accidents (i.e., strokes), can cause specific deficits in speech, facial movements, or use of the extremities. Damage to the spinal cord, such as that caused by a motor vehicle accident or diving accident, will cause specific motor and sensory deficits according to the level where the spinal cord was damaged.
The nervous system is divided into two parts, the central nervous system and the peripheral nervous system. See Figure 6.1 [1] for an image of the entire nervous system. The central nervous system (CNS) includes the brain and the spinal cord. The brain can be described as the interpretation center, and the spinal cord can be described as the transmission pathway. The peripheral nervous system (PNS) consists of the neurological system outside of the brain and spinal cord, including the cranial nerves that branch out from the brain and the spinal nerves that branch out from the spinal cord. The peripheral nervous system can be described as the communication network between the brain and the body parts. Both parts of the nervous system must work correctly for healthy body functioning.
Central and Peripheral Nervous Systems
There major regions of the brain are the cerebrum and cerebral cortex, the diencephalon, the brain stem, and the cerebellum. See Figure 6.2 [2] for an illustration of the cerebellum and the lobes of the cerebrum.
Regions of the Brain
The largest portion of our brain is the cerebrum. The cerebrum is covered by a wrinkled outer layer of gray matter called the cerebral cortex. See Figure 6.3 [3] for an image of the cerebral cortex. The cerebral cortex is responsible for the higher functions of the nervous system such as memory, emotion, and consciousness. The corpus callosum is the major pathway of communication between the right and left hemispheres of the cerebral cortex. The cerebral cortex is further divided into four lobes named the frontal, parietal, occipital, and temporal lobes. [4] Each lobe has specific functions.
The frontal lobe is associated with movement because it contains neurons that instruct cells in the spinal cord to move skeletal muscles. The anterior portion of the frontal lobe is called the prefrontal lobe, and it provides cognitive functions such as planning and problem-solving that are the basis of our personality, short-term memory, and consciousness. Broca’s area is also located in the frontal lobe and is responsible for the production of language and controlling movements responsible for speech. [5]
The parietal lobe processes general sensations from the body. All of the tactile senses are processed in this area, including touch, pressure, tickle, pain, itch, and vibration, as well as general senses of the body, such as proprioception (the sense of body position) and kinesthesia (the sense of movement). [6]
The temporal lobe processes auditory information and is involved with language comprehension and production. Wernicke’s area and Broca’s area are located in the temporal lobe. Wernicke’s area is involved in the comprehension of written and spoken language, and Broca’s area is involved in the production of language. Because regions of the temporal lobe are part of the limbic system, memory is also an important function associated with the temporal lobe. [7] The limbic system is involved with our behavioral and emotional responses needed for survival, such as feeding, reproduction, and the fight – or – flight responses.
The occipital lobe primarily processes visual information. [8]
Information from the rest of the central and peripheral nervous system is sent to the cerebrum through the diencephalon, with the exception of the olfactory nerve that connects directly to the cerebrum. [9] See Figure 6.4 [10] for an illustration of the diencephalon deep within the cerebrum. The diencephalon contains the hypothalamus and the thalamus.
The Diencephalon Containing the Hypothalamus and the Thalamus.
The hypothalamus helps regulate homeostasis such as body temperature, thirst, hunger, and sleep. The hypothalamus is also the executive region in charge of the autonomic nervous system and the endocrine system through its regulation of the anterior pituitary gland. Other parts of the hypothalamus are involved in memory and emotion as part of the limbic system. [11]
The thalamus relays sensory information and motor information in collaboration with the cerebellum. The thalamus does not just pass the information on, but it also processes and prioritizes that information. For example, the portion of the thalamus that receives visual information will influence what visual stimuli are considered important enough to receive further attention from the brain. [12]
The brain stem is composed of the pons and the medulla. The pons and the medulla regulate several crucial autonomic functions in the body, including involuntary functions in the cardiovascular and respiratory systems, vasodilation, and reflexes like vomiting, coughing, sneezing, and swallowing. Cranial nerves also connect to the brain through the brain stem and provide sensory input and motor output. [13]
The cerebellum is located in the posterior part of the brain behind the brain stem and is responsible for fine motor movements and coordination. For example, when the motor neurons in the frontal lobe of the cerebral cortex send a command down the spinal cord to initiate walking, a copy of that instruction is also sent to the cerebellum. Sensory feedback from the muscles and joints, proprioceptive information about the movements of walking, and sensations of balance are sent back to the cerebellum. If the person becomes unbalanced while walking because the ground is uneven, the cerebellum sends out a corrective command to compensate for the difference between the original cerebral cortex command and the sensory feedback. [14]
The spinal cord is a continuation of the brain stem that transmits sensory and motor impulses. The length of the spinal cord is divided into regions that correspond to the level at which spinal nerves pass through the vertebrae. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, the lumbar, and finally the sacral region. [15] The spinal nerves in each of these regions innervate specific parts of the body. See more information under the “Spinal Nerves” section.
Review the anatomy of the brain using following supplementary video.
The peripheral nervous system (PNS) consists of cranial nerves and spinal nerves that exist outside of the brain, spinal cord, and autonomic nervous system. The main function of the PNS is to connect the limbs and organs to the central nervous system (CNS). Sensory information from the body enters the CNS through cranial and spinal nerves. Cranial nerves are connected directly to the brain, whereas spinal nerves are connected to the brain via the spinal cord.
Peripheral nerves are classified as sensory nerves, motor nerves, or a combination of both. Sensory nerves carry impulses from the body to the brain for processing. Motor nerves transmit motor signals from the brain to the muscles to cause movement.
Cranial nerves are directly connected from the periphery to the brain. They are primarily responsible for the sensory and motor functions of the head and neck. There are twelve cranial nerves that are designated by Roman numerals I through XII. See Figure 6.5 [17] for an image of cranial nerves. Three cranial nerves are strictly sensory nerves; five are strictly motor nerves; and the remaining four are mixed nerves. [18] A traditional mnemonic for memorizing the names of the cranial nerves is “On Old Olympus Towering Tops A Finn And German Viewed Some Hops,” in which the initial letter of each word corresponds to the initial letter in the name of each nerve. A second popular mneumonic to assist with memorization is “Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly”.
The oculomotor nerve regulates eye movements by controlling four of the extraocular muscles, lifting the upper eyelid when the eyes point up and for constricting the pupils.
The trochlear nerve and the abducens nerve are both responsible for eye movement, but do so by controlling different extraocular muscles.
The trigeminal nerve regulates skin sensations of the face and controls the muscles used for chewing.
The facial nerve is responsible for the muscles involved in facial expressions, as well as part of the sense of taste and the production of saliva.
The auditory/ vestibulocochlear nerve manages hearing and balance.The glossopharyngeal nerve regulates the controlling muscles in the oral cavity and upper throat, as well as part of the sense of taste and the production of saliva.
The vagus nerve is responsible for contributing to homeostatic control of the organs of the thoracic and upper abdominal cavities.
The accessory nerve controls movements of the neck, along with cervical spinal nerves.The hypoglossal nerve manages the muscles of the lower throat and tongue. [19] Methods for assessing each of these nerves are described in the “Assessing Cranial Nerves” section.
There are 31 spinal nerves that are named based on the level of the spinal cord where they emerge. See Figure 6.6 [21] for an illustration of spinal nerves. There are eight pairs of cervical nerves designated C1 to C8, twelve thoracic nerves designated T1 to T12, five pairs of lumbar nerves designated L1 to L5, five pairs of sacral nerves designated S1 to S5, and one pair of coccygeal nerves. All spinal nerves are combined sensory and motor nerves. Spinal nerves extend outward from the vertebral column to innervate the periphery while also transmitting sensory information back to the CNS. [22]
Spinal Cord and Spinal Nerves
Each spinal nerve innervates a specific region of the body:
C1 provides motor innervation to muscles at the base of the skull. [23] C2 and C3 provide both sensory and motor control to the back of the head and behind the ears. [24]The phrenic nerve arises from nerve roots C3, C4, and C5. This is a vital nerve because it innervates the diaphragm to enable breathing. If a patient’s spinal cord is transected above C3 from an injury, then spontaneous breathing is not possible. [25]
C5 through C8 and T1 combine to form the brachial plexus, a tangled array of nerves that serve the upper limbs and upper back. [26]
The lumbar plexus arises from L1-L5 and innervates the pelvic region and the anterior leg. [27]The sacral plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4. The most significant systemic nerve to come from this plexus is the sciatic nerve. The sciatic nerve is associated with the painful medical condition sciatica, which is back and leg pain as a result of compression or irritation of the sciatic nerve. [28]
When a patient experiences a spinal cord injury, the degree of paralysis can be predicted by the location of the spinal cord injury. It is also important to remember when a patient has a spinal cord injury and their motor nerves are damaged, their sensory nerves may still be intact. If this occurs, the patient can still feel sensation even if they can’t move the extremity. Therefore, don’t assume that a paralyzed patient cannot feel pain in the affected extremity because this is not always the case.
The nervous system receives information about the environment around us (sensation) and generates responses to that information (motor responses). The process of integration combines sensory perceptions and higher cognitive functions such as memories, learning, and emotion while producing a response.
Sensation is defined as receiving information about the environment. The major senses are taste, smell, touch, sight, and hearing. Additional sensory stimuli are also provided from inside the body, such as the stretch of an organ wall or the concentration of certain ions in the blood. [29]
The nervous system produces a response based on the stimuli perceived by sensory nerves. For example, withdrawing a hand from a hot stove is an example of a response to a painfully hot stimulus. Responses can be classified by those that are voluntary (such as contraction of a skeletal muscle) and those that are involuntary (such as contraction of smooth muscle in the intestine). Voluntary responses are governed by the somatic nervous system, and involuntary responses are governed by the autonomic nervous system. [30]
Integration occurs when stimuli received by sensory nerves are communicated to the nervous system and the information is processed, leading to the generation of a conscious response. Consider this example of sensory integration. A batter in a baseball game does not automatically swing when they see the baseball thrown to them by the pitcher. First, the trajectory of the ball and its speed will need to be considered before creating the motor response of a swing. Then, integration will occur as the batter generates a conscious decision of whether to swing or not. Perhaps the count is three balls and one strike, and the batter decides to let this pitch go by in the hope of getting a walk to first base. Perhaps the batter is afraid to strike out and doesn’t swing, or maybe the batter learned the pitcher’s nonverbal cues the previous time at bat and is confident to take a swing at an anticipated fast ball. All of these considerations are included as part of the batter’s integration response and the higher level functioning that occurs in the cerebral cortex. [31]
This work is a derivative of Anatomy & Physiology by OpenStax and is licensed under CC BY 4.0. Access for free at https://openstax .org /books/anatomy-and-physiology /pages/1-introduction ↵.
Forciea, B. (2015, May 12). Anatomy and physiology: Central nervous system: Brain anatomy v2.0. [Video]. YouTube. All rights reserved. Video used with permission. https://youtu .be/DBRdInd2-Vg ↵.
Forciea, B. (2015, May 12). Anatomy and physiology: Nervous system: Cranial nerves (v2.0). [Video]. YouTube. All rights reserved. Video used with permission. https://youtu .be/JBEZh6CHogo ↵.
"1008694237-vector .png" by VectorMine on Shutterstock. All rights reserved. Imaged used with purchased permission. ↵.
This work is a derivative of Anatomy and Physiology by Boundless .com and is licensed under CC BY-SA 4.0 ↵.
This work is a derivative of Anatomy and Physiology by Boundless .com and is licensed under CC BY-SA 4.0 ↵.
This work is a derivative of Anatomy and Physiology by Boundless .com and is licensed under CC BY-SA 4.0 ↵.
This work is a derivative of Anatomy and Physiology by Boundless .com and is licensed under CC BY-SA 4.0 ↵.
The neurological exam is a clinical assessment of the functioning of the central nervous system (CNS) and peripheral nervous system (PNS). See Figure 6.7 [1] for an image of the anatomical underpinnings of the neurological exam. Several tests are available when performing a neurological assessment; the tests included in the assessment are selected based on the patient’s medical condition and the neurological symptoms they are experiencing. The range of tests that can be included in a neurological exam include evaluation of mental status, cranial nerves, sensory functioning, motor strength, cerebellar functioning, and reflexes. The mental status exam assesses the higher cognitive functions such as memory, orientation, and language associated with the cerebrum and cerebral cortex. The cranial nerve exam tests the sensory and motor functioning of the 12 cranial nerves that connect to the diencephalon and the brain stem. The sensory response and motor strength tests evaluate functions associated with the spinal nerves. The cerebellar function tests evaluate balance, muscle tone, and coordination of voluntary movements. Deep tendon reflexes may also be used to assess the health of the nervous system. [2] Each of these components of a neurological exam is further described in the remaining sections of this chapter.
Anatomical Underpinnings of Neurological Exam
The type of neurological exam performed is based on the patient’s reason for seeking care, their current medical condition, and the practice setting.
Routine neurological exams performed by registered nurses during their daily clinical practice include assessing mental status and level of consciousness, pupillary response, motor strength, sensation, and gait. The Glasgow Coma Scale is also frequently used to objectively monitor level of consciousness in patients with neurological damage such as a head injury or cerebrovascular accident (i.e., stroke). [3]
A comprehensive neurologic exam is performed on patients with a neurological concern. This exam is more extensive and may be performed in specialty settings or by advanced practice nurses. In addition to the components included in a routine neurological exam, the examiner may also assess cranial nerves, detailed cerebellar function, deep tendon reflexes, and complete a Mini-Mental State Exam (MMSE).
Periodic reevaluations are performed by registered nurses when the patient has experienced an acute injury or illness causing neurological deficits that require frequent monitoring for change in condition. For example, a patient admitted to the hospital for an acute cerebrovascular accident (i.e., stroke) will have their neurological status rechecked and documented frequently according to agency policy. See Figure 6.8 [4] of a nurse assessing a patient’s neurological status in an intensive care unit.
Nurse Assessing Patient’s Neurological Status in ICU
Giddens J. F. A survey of physical examination techniques performed by RNs: Lessons for nursing education. Journal of Nursing Education. 2007; 46 (2):83–87. ↵ [PubMed : 17315568 ] [CrossRef]
Routine assessment of a patient’s mental status by registered nurses includes evaluating their level of consciousness, as well as their overall appearance, general behavior, affect and mood, general speech, and cognitive performance. [1] , [2] See the “General Survey Assessment” chapter for more information about an overall mental status assessment.
Level of consciousness refers to a patient’s level of arousal and alertness. [3] Assessing a patient’s orientation to time, place, and person is a quick indicator of cognitive functioning. Level of consciousness is typically evaluated on admission to a facility to establish a patient’s baseline status and then frequently monitored every shift for changes in condition. [4] To assess a patient’s orientation status, ask, “What is your name? Where are you? What day is it?” If the patient is unable to recall a specific date, it may be helpful to ask them the day of the week, the month, or the season to establish a baseline of their awareness level.
A normal level of orientation is typically documented as, “Patient is alert and oriented to person, place, and time,” or by the shortened phrase, “Alert and oriented x 3.” [5] If a patient is confused, an example of documentation is, “Patient is alert and oriented to self, but disoriented to time and place.”
There are many screening tools that can be used to further objectively assess a patient’s mental status and cognitive impairment. Common screening tools used frequently by registered nurses to assess mental status include the Glasgow Coma Scale, the National Institutes of Health Stroke Scale (NIHSS), and the Mini-Mental State Exam (MMSE).
The Glasgow Coma Scale (GCS) is a standardized tool used to objectively assess and continually monitor a patient’s level of consciousness when damage has occurred, such as after a head injury or a cerebrovascular accident (stroke). See Figure 6.9 [6] for an image of the Glasgow Coma Scale. Three primary areas assessed in the GCS include eye opening, verbal response, and motor response. Scores are added from these three categories to assign a patient’s level of responsiveness. Scores ranging from 15 or higher are classified as the best response, less than 8 is classified as comatose, and 3 or less is classified as unresponsive.
Glasgow Coma Scale
The National Institutes of Health Stroke Scale (NIHSS) is a standardized tool that is commonly used to assess patients suspected of experiencing an acute cerebrovascular accident (i.e., stroke). [7] The three most predictive findings that occur during an acute stroke are facial drooping, arm drift/weakness, and abnormal speech. Use the following hyperlink to view the stroke scale.
A commonly used mnemonic regarding assessment of individuals suspected of experiencing a stroke is “BEFAST.” BEFAST stands for Balance, Eyes, Face, Arm, and Speech Test.
B: Does the person have a sudden loss of balance? E: Has the person lost vision in one or both eyes? F: Does the person’s face look uneven? A: Is one arm weak or numb? S: Is the person’s speech slurred? Are they having trouble speaking or seem confused? T: Time to call for assistance immediatelyThe Mini-Mental Status Exam (MMSE) is commonly used to assess a patient’s cognitive status when there is a concern of cognitive impairment. The MMSE is sensitive and specific in detecting delirium and dementia in patients at a general hospital and in residents of long-term care facilities. [8] Delirium is acute, reversible confusion that can be caused by several medical conditions such as fever, infection, and lack of oxygenation. Dementia is chronic, irreversible confusion and memory loss that impacts functioning in everyday life.
Prior to administering the MMSE, ensure the patient is wearing their glasses and/or hearing aids, if needed. [9] A patient can score up to 30 points by accurately responding and following directions given by the examiner. A score of 24-30 indicates no cognitive impairment, 18-23 indicates mild cognitive impairment, and a score less than 18 indicates severe cognitive impairment. See Figure 6.10 [10] for an image of one of the questions on the MMSE regarding interlocking pentagons.
MMSE Question on Interlocking Pentagons
Martin, D. C. The mental status examination. In Walker, H. K., Hall, W. D., Hurst, J. W. (Eds.), Clinical methods: The history, physical, and laboratory examinations (3rd ed.). Butterworths. https://www .ncbi.nlm .nih.gov/books/NBK320/ ↵. [PubMed : 21250045 ]
Giddens J. F. A survey of physical examination techniques performed by RNs: Lessons for nursing education. Journal of Nursing Education. 2007; 46 (2):83–87. ↵ [PubMed : 17315568 ] [CrossRef]
Huntley A. Documenting level of consciousness. Nursing. 2008; 38 (8):63–64. ↵ [PubMed : 18648313 ] [CrossRef]
McDougall G. J. A review of screening instruments for assessing cognition and mental status in older adults. The Nurse Practitioner. 1990; 15 (11):18–28. ↵ [PMC free article : PMC6751405 ] [PubMed : 2255423 ]
Huntley A. Documenting level of consciousness. Nursing. 2008; 38 (8):63–64. ↵ [PubMed : 18648313 ] [CrossRef]
"glasgow-coma-scale-gcs-600w-309293585 .jpg" by joshya on Shutterstock. All rights reserved. Imaged used with purchased permission. ↵.
McDougall G. J. A review of screening instruments for assessing cognition and mental status in older adults. The Nurse Practitioner. 1990; 15 (11):18–28. ↵ [PMC free article : PMC6751405 ] [PubMed : 2255423 ]
Koder-Anne D., Klahr A. Training nurses in cognitive assessment: Uses and misuses of the mini-mental state examination. Educational Gerontology. 2010; 36 (10/11):827–833. ↵ [CrossRef]
"InterlockingPentagons.svg" by Jfdwolff[2] is licensed under CC BY-SA 3.0 ↵.When performing a comprehensive neurological exam, examiners may assess the functioning of the cranial nerves. When performing these tests, examiners compare responses of opposite sides of the face and neck. Instructions for assessing each cranial nerve are provided below.
Ask the patient to identify a common odor, such as coffee or peppermint, with their eyes closed. See Figure 6.11 [1] for an image of a nurse performing an olfactory assessment.
Assessing Cranial Nerve I (Olfactory)
Be sure to provide adequate lighting when performing a vision assessment.
Far vision is tested using the Snellen chart. See Figure 6.12 [2] for an image of a Snellen chart. The numerator of the fractions on the chart indicate what the individual can see at 20 feet, and the denominator indicates the distance at which someone with normal vision could see this line. For example, a result of 20/40 indicates this individual can see this line at 20 feet but someone with normal vision could see this line at 40 feet.
Test far vision by asking the patient to stand 20 feet away from a Snellen chart. Ask the patient to cover one eye and read the letters from the lowest line they can see. [3] Record the corresponding result in the furthermost right-hand column, such as 20/30. Repeat with the other eye. If the patient is wearing glasses or contact lens during this assessment, document the results as “corrected vision.” Repeat with each eye, having the patient cover the opposite eye. Alternative charts are available for children or adults who can’t read letters in English.
Near vision is assessed by having a patient read from a prepared card from 14 inches away. See Figure 6.13 [4] for a card used to assess near vision.
Assessing Near Vision
Cranial nerve III, IV, and VI (oculomotor, trochlear, abducens nerves) are tested together.
Test eye movement by using a penlight. Stand 1 foot in front of the patient and ask them to follow the direction of the penlight with only their eyes. At eye level, move the penlight left to right, right to left, up and down, upper right to lower left, and upper left to lower right. Watch for smooth movement of the eyes in all fields. An unexpected finding is involuntary eye movement which may cause the eye to move rapidly from side to side, up and down, or in a circle, and may slightly blur vision referred to as nystagmus.
Test bilateral pupils to ensure they are equally round and reactive to light and accommodation. Dim the lights of the room before performing this test.
Pupils should be round and bilaterally equal in size. The diameter of the pupils usually ranges from two to five millimeters. Emergency clinicians often encounter patients with the triad of pinpoint pupils, respiratory depression, and coma related to opioid overuse.
Test pupillary reaction to light. Using a penlight, approach the patient from the side, and shine the penlight on one pupil. Observe the response of the lighted pupil, which is expected to quickly constrict. The pupil where you shine the light should constrict (direct reaction) and so should the other one (consensual reaction). Repeat by shining the light on the other pupil. Both pupils should react in the same manner to light. See Figure 6.14 [5] for an image of a nurse assessing a patient’s pupillary reaction to light. An unexpected finding is when one pupil is larger than the other or one pupil responds more slowly than the other to light, which is often referred to as a “sluggish response.”
Test eye convergence and accommodation. Recall that accommodation refers to the ability of the eye to adjust from near to far vision, with pupils constricting for near vision and dilating for far vision. Convergence refers to the action of both eyes moving inward as they focus on a close object using near vision. Ask the patient to look at a near object (4-6 inches away from the eyes), and then move the object out to a distance of 12 inches. Pupils should constrict while viewing a near object and then dilate while looking at a distant object, and both eyes should move together. See Figure 6.15 [6] for an image of a nurse assessing convergence and accommodation.
The acronym PERRLA is commonly used in medical documentation and refers to, “pupils are equal, round and reactive to light and accommodation.”
Assessing Pupillary Reaction to Light
Assessing Eye Convergence and Accommodation
