![Examining the Sensory System
• The sensory system is even more complex than the motor system, because sensory modalities
are more widespread throughout the central and peripheral nervous systems. The sensory
examination is largely subjective and requires the cooperation of the patient.
• Assessment of the sensory system involves tests for tactile sensation, superficial pain,
temperature, vibration, and position sense (proprioception). During the sensory assessment, the
patient’s eyes are closed. Simple directions and reassurance that the examiner will not hurt or
startle the patient encourage the cooperation of the patient.
• Tactile sensation is assessed by lightly touching a cotton wisp or fingertip to corresponding
areas on each side of the body
• Pain and temperature sensations are transmitted together in the lateral part of the spinal cord,
so it is unnecessary to test for temperature sense in most circumstances. Determining the
patient’s sensitivity to a sharp object can assess superɹcial pain perception.
• Vibration and proprioception are transmitted together in the posterior part of the cord. Vibration
may be evaluated through the use of a low-frequency (128 or 256 Hertz [Hz]) tuning fork.
• Position sense or proprioception may be determined by asking the patient to close both eyes
and indicate, as the great toe or index finger is alternately moved up and down, in which direction
movement has taken place.
• Integration of sensation in the brain is evaluated by testing two-point discrimination. When the
patient is touched with two sharp objects simultaneously, are they perceived as two or as one?](https://image.slidesharecdn.com/chapter13assessmentoftheneurologicfunction-250815154405-8d54c15d/85/CHAPTER-13-ASSESSMENT-OF-THE-NEUROLOGIC-FUNCTION-pdf-24-320.jpg)
CHAPTER 13 ASSESSMENT OF THE NEUROLOGIC FUNCTION.pdf
- 1. Assessment of Neurologic Function Kenneth M. Sabido, RN, MN
- 2. •Nurses in many practice settings encounter patients with altered neurologic function. •Disorders of the nervous system can occur at any time during the lifespan and can vary from mild, self-limiting symptoms to devastating, life-threatening disorders.
- 3. Anatomic and Physiologic Overview The nervous system consists of two major parts: 1. the central nervous system (CNS), including the brain and spinal cord, and 2. the peripheral nervous system (PNS), which includes the cranial nerves, spinal nerves, and autonomic nervous system. The function of the nervous system is to control motor, sensory, autonomic, cognitive, and behavioral activities.
- 4. Cells of the Nervous System • The basic functional unit of the brain is the neuron . It is composed of dendrites, a cell body, and an axon. • The dendrites are branch-type structures for receiving electrochemical messages. • The axon is a long projection that carries electrical impulses away from the cell body
- 5. Neurotransmitter s • Neurotransmitters communicate messages from one neuron to another or from a neuron to a target cell, such as muscle or endocrine cells. Neurotransmitters are manufactured and stored in synaptic vesicles.
- 6. The Central Nervous System The Brain is divided into three major areas: the cerebrum, the brain stem, and the cerebellum. • The cerebrum is composed of two hemispheres, the thalamus, the hypothalamus, and the basal ganglia. • The brain stem includes the midbrain, pons, and medulla. • The cerebellum is located under the cerebrum and behind the brain stem.
- 7. Cerebrum • Frontal—the largest lobe, located in the front of the brain. The major functions of this lobe are concentration, abstract thought, information storage or memory, and motor function. It contains Broca’s area, which is located in the left hemisphere and is critical for motor control of speech. • Parietal—a predominantly sensory lobe posterior to the frontal lobe. This lobe analyzes sensory information and relays the interpretation of this information to other cortical areas and is essential to a person’s awareness of body position in space, size and shape discrimination, and right– left orientation (Hickey, 2009). • Temporal—located inferior to the frontal and parietal lobes, this lobe contains the auditory receptive areas and plays a role in memory of sound and understanding of language and music. • Occipital—located posterior to the parietal lobe, this lobe is responsible for visual interpretation and memory.
- 8. Brain Stem • The brain stem consists of the midbrain, pons, and medulla oblongata. The midbrain connects the pons and the cerebellum with the cerebral hemispheres; it contains sensory and motor pathways and serves as the center for auditory and visual reflexes. Cranial nerves III and IV originate in the midbrain. Cerebellum • The cerebellum is posterior to the midbrain and pons, and below the occipital lobe . The cerebellum integrates sensory information to provide smooth coordinated movement. It controls fine movement, balance, and position (postural) sense or proprioception (awareness of position of body parts without looking at them).
- 9. Structures Protecting the Brain The meninges (fibrous connective tissues that cover the brain and spinal cord) provide protection, support, and nourishment. The layers of the meninges are the dura mater, arachnoid, and pia mater • Dura mater—the outermost layer; covers the brain and the spinal cord. It is tough, thick, inelastic, fibrous, and gray. • Arachnoid—the middle membrane; an extremely thin, delicate membrane that closely resembles a spider web (hence the name arachnoid). • Pia mater—the innermost, thin, transparent layer that hugs the brain closely and extends into every fold of the brain’s surface
- 10. Cerebrospinal Fluid • CSF is a clear and colorless fluid that is produced in the choroid plexus of the ventricles and circulates around the surface of the brain and the spinal cord. Cerebral Circulation • The brain does not store nutrients and requires a constant supply of oxygen. These needs are met through cerebral circulation; the brain receives approximately 15% of the cardiac output, or 750 mL per minute of blood flow. Blood–Brain Barrier • The CNS is inaccessible to many substances that circulate in the blood plasma (e.g., dyes, medications, and antibiotic agents) because of the blood–brain barrier. The Spinal Cord • The spinal cord is continuous with the medulla, extending from the cerebral hemispheres and serving as the connection between the brain and the periphery.
- 11. The Peripheral Nervous System • The peripheral nervous system includes the cranial nerves, the spinal nerves, and the autonomic nervous system.
- 12. Cranial Nerves • Twelve pairs of cranial nerves emerge from the lower surface of the brain and pass-through openings in the base of the skull.
- 14. Spinal Nerves The spinal cord is composed of 31 pairs of spinal nerves: 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal.
- 15. Autonomic Nervous System -The autonomic nervous system regulates the activities of internal organs such as the heart, lungs, blood vessels, digestive organs, and glands. -Maintenance and restoration of internal homeostasis is largely the responsibility of the autonomic nervous system. -There are two major divisions: The sympathetic nervous system, with predominantly excitatory responses (most notably the “fight-or-flight” response) The parasympathetic nervous system, which controls mostly visceral functions.
- 16. Sympathetic Nervous System • The sympathetic division of the autonomic nervous system is best known for its role in the body’s flight-or-fight response. Under stress from either physical or emotional causes, sympathetic impulses increase greatly. As a result, the bronchioles dilate for easier gas exchange; the heart’s contractions are stronger and faster Parasympathetic Nervous System • The parasympathetic nervous system functions as the dominant controller for most visceral functions; the primary neurotransmitter is acetylcholine. During quiet, non-stressful conditions, impulses from parasympathetic fibers (cholinergic) predominate.
- 17. Assessment of the Nervous System Health History • An important aspect of the neurologic assessment is the history of the present illness. The initial interview provides an excellent opportunity to systematically explore the patient’s current condition and related events while simultaneously observing overall appearance, mental status, posture, movement, and affect. Depending on the patient’s condition, the nurse may need to rely on yes-or-no answers to questions, a review of the medical record, input from witnesses or the family, or a combination of these.
- 18. • Pain Pain is considered an unpleasant sensory perception and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Pain is therefore considered multidimensional and entirely subjective. Pain can be acute or chronic. • Seizures Seizures are the result of abnormal electrical discharges in the cerebral cortex, which then manifest as an alteration in sensation, behavior, movement, perception, or consciousness. • Dizziness and Vertigo Dizziness is an abnormal sensation of imbalance or movement. Vertigo is usually a manifestation of vestibular dysfunction. It can be so severe as to result in spatial disorientation, lightheadedness, loss of equilibrium (staggering), and nausea and vomiting. • Visual Disturbances Visual defects that cause people to seek health care can range from the decreased visual acuity associated with aging to sudden blindness caused by glaucoma. • Muscle Weakness Muscle weakness is a common manifestation of neurologic disease. It frequently coexists with other symptoms of disease and can affect a variety of muscles, causing a wide range of disability. • Abnormal Sensation Abnormal sensation is a neurologic manifestation of both central and peripheral nervous system disease. Altered sensation can affect small or large areas of the body. It is frequently associated with weakness or pain and is potentially disabling.
- 19. Past Health, Family, and Social History • The nurse may inquire about any family history of genetic diseases . A review of the medical history, including a system-by- system evaluation, is part of the health history. The nurse should be aware of any history of trauma or falls that may have involved the head or spinal cord. Questions regarding the use of alcohol, medications, and illicit drugs are also relevant. The history-taking portion of the neurologic assessment is critical and, in many cases of neurologic disease, leads to an accurate diagnosis.
- 20. Physical Assessment • The neurologic examination is a systematic process that includes a variety of clinical tests, observations, and assessments designed to evaluate the neurologic status of a complex system. • The brain and spinal cord cannot be examined as directly as other systems of the body. • Therefore, much of the neurologic examination is an indirect evaluation that assesses the function of the specific body part or parts controlled by the nervous system. A neurologic assessment is divided into five components: consciousness and cognition, cranial nerves, motor system, sensory system, and reflexes. One or more components may become the priority assessment, depending on the patient’s condition.
- 21. Assessing Consciousness and Cognition • Mental Status An assessment of mental status begins by observing the patient’s appearance and behavior, noting dress, grooming, and personal hygiene. Posture, gestures, movements, and facial expressions often provide important information about the patient. Does the patient appear to be aware of and interact with the surroundings? • Intellectual Function A person with an average intelligence quotient (IQ) can repeat seven digits without faltering and can recite five digits backward. The examiner might ask the patient to count backward from 100 or to subtract 7 from 100, then 7 from that, and so forth (referred to as serial 7s). • Thought Content During the interview, it is important to assess the patient’s thought content. Are the patient’s thoughts spontaneous, natural, clear, relevant, and coherent? Does the patient have any fixed ideas, illusions, or preoccupations? • Emotional Status An assessment of consciousness and cognition also includes the patient’s emotional status. Is the patient’s affect (external manifestation of mood) natural and even, or irritable and angry, anxious, apathetic or flat, or euphoric? • Language Ability The person with normal neurologic function can understand and communicate in spoken and written language. • Impact on Lifestyle The nurse assesses the impact of any impairment on the patient’s lifestyle. Issues to consider include the limitations imposed on the patient by any cognitive deɹcit and the patient’s role in society, including family and community roles. • Level of Consciousness Consciousness is the patient’s wakefulness and ability to respond to the environment. Level of consciousness is the most sensitive indicator of neurologic function. To assess level of consciousness, the examiner observes for alertness and ability to follow commands.
- 22. Examining the Cranial Nerves • Cranial nerves are assessed when level of consciousness is decreased, with brain stem pathology, or in the presence of peripheral nervous system disease
- 23. Examining the Motor System • Motor Ability A thorough examination of the motor system includes an assessment of muscle size and tone as well as strength, coordination, and balance. The patient is instructed to walk across the room, if possible, while the examiner observes posture and gait. • Muscle Strength Assessing the patient’s ability to flex or extend the extremities against resistance tests muscle strength. The function of an individual muscle or group of muscles is evaluated by placing the muscle at a disadvantage. Clinicians use a five-point scale to rate muscle strength. • Balance and Coordination Cerebellar and basal ganglia inɻuence on the motor system is reɻected in balance control and coordination. Coordination in the hands and upper extremities is tested by having the patient perform rapid, alternating movements and point-to-point testing. The Romberg test is a screening test for balance that can be done with the patient seated or standing The patient can be seated or stand with feet together and arms at the side, first with eyes open and then with both eyes closed for 20 seconds (Bader & Littlejohns, 2010; Weber & Kelley, 2010).
- 24. Examining the Sensory System • The sensory system is even more complex than the motor system, because sensory modalities are more widespread throughout the central and peripheral nervous systems. The sensory examination is largely subjective and requires the cooperation of the patient. • Assessment of the sensory system involves tests for tactile sensation, superficial pain, temperature, vibration, and position sense (proprioception). During the sensory assessment, the patient’s eyes are closed. Simple directions and reassurance that the examiner will not hurt or startle the patient encourage the cooperation of the patient. • Tactile sensation is assessed by lightly touching a cotton wisp or fingertip to corresponding areas on each side of the body • Pain and temperature sensations are transmitted together in the lateral part of the spinal cord, so it is unnecessary to test for temperature sense in most circumstances. Determining the patient’s sensitivity to a sharp object can assess superɹcial pain perception. • Vibration and proprioception are transmitted together in the posterior part of the cord. Vibration may be evaluated through the use of a low-frequency (128 or 256 Hertz [Hz]) tuning fork. • Position sense or proprioception may be determined by asking the patient to close both eyes and indicate, as the great toe or index finger is alternately moved up and down, in which direction movement has taken place. • Integration of sensation in the brain is evaluated by testing two-point discrimination. When the patient is touched with two sharp objects simultaneously, are they perceived as two or as one?
- 25. Examining the Reflexes • Deep Tendon Reflexes A reflex hammer is used to elicit a deep tendon reɻex. The handle of the hammer is held loosely between the thumb and index finger, allowing a full swinging motion. Biceps Reflex. The biceps reflex is elicited by striking the biceps tendon over a slightly flexed elbow Triceps Reflex. To elicit a triceps reflex, the patient’s arm is flexed at the elbow and hanging freely at the side. Brachioradialis Reflex. With the patient’s forearm resting on the lap or across the abdomen, the brachioradialis reflex is assessed Patellar Reflex. The patellar reflex is elicited by striking the patellar tendon just below the patella. Achilles Reflex. To elicit an Achilles reflex, the foot is dorsiflexed at the ankle and the hammer strikes the stretched Achilles tendon Clonus. When reflexes are hyperactive, a movement called clonus may be elicited. If the foot is abruptly dorsiflexed, it may continue to “beat” two or three times before it settles into a position of rest
- 26. Examining the Reflexes • Superficial Reflexes The major superficial reflexes include corneal, palpebral, gag, upper/lower abdominal, cremasteric (men only), and perianal. These reflexes are graded differently than the motor reflexes and are noted to be present (+) or absent (– ). Of these, only the corneal, gag, and plantar reflexes are commonly tested. • Pathologic Reflexes Pathologic reflexes are seen in the presence of neurologic disease; they often represent emergence of earlier reflexes that disappeared with maturity of the nervous system. A pathologic reflex indicative of CNS disease affecting the corticospinal tract is the Babinski reflex (sign). In a person with an intact CNS, if the lateral aspect of the sole of the foot is stroked, the toes contract and draw together. However, in a person who has CNS disease of the motor system, the toes fan out and draw back (Jarvis, 2012)
- 27. Gerontologic Considerations • During the normal aging process, the nervous system undergoes many changes and is more vulnerable to illness. Age-related changes in the nervous system vary in degree and must be distinguished from those due to disease.
- 28. • Structural and Physiologic Changes As the brain ages, neurons are lost, leading to a decrease in the number of synapses and neurotransmitters. This results in slowed nerve conduction and response time. Brain weight is decreased, and the ventricle size increases to maintain cranial volume. • Motor Alterations Reduced nerve input into muscle contributes to an overall reduction in muscle bulk, with atrophy most easily noted in the hands. Changes in motor function often result in decreased strength and agility, with increased reaction time. • Sensory Alterations Tactile sensation is dulled in the older adult due to a decrease in the number of sensory receptors. Sensitivity to glare, decreased peripheral vision, and a constricted visual field occur due to degeneration of visual pathways, resulting in disorientation, especially at night when there is little or no light in the room. A decreased sense of smell may present a safety hazard. • Temperature Regulation and Pain Perception The older adult patient may feel cold more readily than heat and may require extra covering when in bed; a room temperature somewhat higher than usual may be desirable. Reaction to painful stimuli may be decreased with age (Kunz et al., 2009). • Mental Status Although mental processing time decreases with age, memory, language, and judgment capacities remain intact. Change in mental status should never be assumed to be a normal part of aging. Delirium (transient mental confusion, usually with delusions and hallucinations) is seen in older adult patients who have underlying CNS damage or are experiencing an acute condition such as infection, adverse medication reaction, or dehydration.
- 29. Diagnostic Evaluation • A wide range of diagnostic studies may be performed in patients with altered neurologic function. The nurse should educate the patient about the purpose, what to expect, and any possible side effects related to these examinations prior to testing.
- 30. Computed Tomography Scanning Magnetic Resonance Imaging Positron Emission Tomography Single-Photon Emission Computed Tomography Cerebral Angiography Myelography Noninvasive Carotid Flow Studies Transcranial Doppler Electroencephalogr aphy Electromyography Nerve Conduction Studies Evoked Potential Studies Lumbar Puncture and Examination of Cerebrospinal Fluid Diagnostic Evaluation
- 31. REFERENCE: Brunner Suddarth’s textbook of medical- surgical nursing by Brunner, Lillian Sholtis Cheever, Kerry H. Hinkle, Janice L. Suddarth, Doris Smith (z-lib.org)