Module 11: The Neurological Exam

Lesson 1: Overview of the Neurological Exam

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Dưới đây là danh sách những thuật ngữ Y khoa của module The Neurological Exam.
Khái quát được số lượng thuật ngữ sẽ xuất hiện trong bài đọc và nghe sẽ giúp bạn thoải mái tiêu thụ nội dung hơn. Sau khi hoàn thành nội dung đọc và nghe, bạn hãy quay lại đây và luyện tập (practice) để quen dần các thuật ngữ này. Đừng ép bản thân phải nhớ các thuật ngữ này vội vì bạn sẽ gặp và ôn lại danh sách này trong những bài học (lesson) khác của cùng một module.

Medical Terminology: The Neurological Exam

accommodation
in vision, a change in the ability of the eye to focus on objects at different distances
accommodation–convergence reflex
coordination of somatic control of the medial rectus muscles of either eye with the parasympathetic control of the ciliary bodies to maintain focus while the eyes converge on visual stimuli near to the face
anterograde amnesia
inability to form new memories from a particular time forward
aphasia
loss of language function
ataxia
movement disorder related to damage of the cerebellum characterized by loss of coordination in voluntary movements
Babinski sign
dorsiflexion of the foot with extension and splaying of the toes in response to the plantar reflex, normally suppressed by corticospinal input
cerebrocerebellum
lateral regions of the cerebellum; named for the significant input from the cerebral cortex
check reflex
response to a release in resistance so that the contractions stop, or check, movement
clasp-knife response
sign of UMN disease when a patient initially resists passive movement of a muscle but will quickly release to a lower state of resistance
conduction aphasia
loss of language function related to connecting the understanding of speech with the production of speech, without either specific function being lost
conductive hearing
hearing dependent on the conduction of vibrations of the tympanic membrane through the ossicles of the middle ear
conjugate gaze
coordinated movement of the two eyes simultaneously in the same direction
convergence
in vision, the movement of the eyes so that they are both pointed at the same point in space, which increases for stimuli that are closer to the subject
coordination exam
major section of the neurological exam that assesses complex, coordinated motor functions of the cerebellum and associated motor pathways
cortico-ponto-cerebellar pathway
projection from the cerebral cortex to the cerebellum by way of the gray matter of the pons
cranial nerve exam
major section of the neurological exam that assesses sensory and motor functions of the cranial nerves and their associated central and peripheral structures
cytoarchitecture
study of a tissue based on the structure and organization of its cellular components; related to the broader term, histology
deep tendon reflex
another term for stretch reflex, based on the elicitation through deep stimulation of the tendon at the insertion
diplopia
double vision resulting from a failure in conjugate gaze
edema
fluid accumulation in tissue; often associated with circulatory deficits
embolus
obstruction in a blood vessel such as a blood clot, fatty mass, air bubble, or other foreign matter that interrupts the flow of blood to an organ or some part of the body
episodic memory
memory of specific events in an autobiographical sense
expressive aphasia
loss of the ability to produce language; usually associated with damage to Broca’s area in the frontal lobe
extrinsic muscles of the tongue
muscles that are connected to other structures, such as the hyoid bone or the mandible, and control the position of the tongue
fasciculation
small muscle twitch as a result of spontaneous activity from an LMN
fauces
opening from the oral cavity into the pharynx
fibrillation
in motor responses, a spontaneous muscle action potential that occurs in the absence of neuromuscular input, resulting from LMN lesions
flaccid paralysis
loss of voluntary muscle control and muscle tone, as the result of LMN disease
flaccidity
presentation of a loss of muscle tone, observed as floppy limbs or a lack of resistance to passive movement
flocculonodular lobe
lobe of the cerebellum that receives input from the vestibular system to help with balance and posture
gait
rhythmic pattern of alternating movements of the lower limbs during locomotion
gait exam
major section of the neurological exam that assesses the cerebellum and descending pathways in the spinal cord through the coordinated motor functions of walking; a portion of the coordination exam
gnosis
in a neurological exam, intuitive experiential knowledge tested by interacting with common objects or symbols
graphesthesia
perception of symbols, such as letters or numbers, traced in the palm of the hand
hemisection
cut through half of a structure, such as the spinal cord
hemorrhagic stroke
disruption of blood flow to the brain caused by bleeding within the cranial vault
hyperflexia
overly flexed joints
hypotonicity
low muscle tone, a sign of LMN disease
hypovolemia
decrease in blood volume
inferior cerebellar peduncle (ICP)
input to the cerebellum, largely from the inferior olive, that represents sensory feedback from the periphery
inferior olive
large nucleus in the medulla that receives input from sensory systems and projects into the cerebellar cortex
internuclear ophthalmoplegia
deficit of conjugate lateral gaze because the lateral rectus muscle of one eye does not contract resulting from damage to the abducens nerve or the MLF
intorsion
medial rotation of the eye around its axis
intrinsic muscles of the tongue
muscles that originate out of, and insert into, other tissues within the tongue and control the shape of the tongue
ischemic stroke
disruption of blood flow to the brain because blood cannot flow through blood vessels as a result of a blockage or narrowing of the vessel
jaw-jerk reflex
stretch reflex of the masseter muscle
localization of function
principle that circumscribed anatomical locations are responsible for specific functions in an organ system
medial longitudinal fasciculus (MLF)
fiber pathway that connects structures involved in the control of eye and head position, from the superior colliculus to the vestibular nuclei and cerebellum
mental status exam
major section of the neurological exam that assesses cognitive functions of the cerebrum
middle cerebellar peduncle (MCP)
large, white-matter bridge from the pons that constitutes the major input to the cerebellar cortex
motor exam
major section of the neurological exam that assesses motor functions of the spinal cord and spinal nerves
neurological exam
clinical assessment tool that can be used to quickly evaluate neurological function and determine if specific parts of the nervous system have been affected by damage or disease
paramedian pontine reticular formation (PPRF)
region of the brain stem adjacent to the motor nuclei for gaze control that coordinates rapid, conjugate eye movements
paresis
partial loss of, or impaired, voluntary muscle control
plantar reflex
superficial reflex initiated by gentle stimulation of the sole of the foot
praxis
in a neurological exam, the act of doing something using ready knowledge or skills in response to verbal instruction
procedural memory
memory of how to perform a specific task
pronator drift
sign of contralateral corticospinal lesion when the one arm will drift into a pronated position when held straight out with the palms facing upward
receptive aphasia
loss of the ability to understand received language, such as what is spoken to the subject or given in written form
red nucleus
nucleus in the midbrain that receives output from the cerebellum and projects onto the spinal cord in the rubrospinal tract
retrograde amnesia
loss of memories before a particular event
Rinne test
use of a tuning fork to test conductive hearing loss versus sensorineural hearing loss
Romberg test
test of equilibrium that requires the patient to maintain a straight, upright posture without visual feedback of position
rubrospinal tract
descending tract from the red nucleus of the midbrain that results in modification of ongoing motor programs
saccade
small, rapid movement of the eyes used to locate and direct the fovea onto visual stimuli
sensorineural hearing
hearing dependent on the transduction and propagation of auditory information through the neural components of the peripheral auditory structures
sensory exam
major section of the neurological exam that assesses sensory functions of the spinal cord and spinal nerves
short-term memory
capacity to retain information actively in the brain for a brief period of time
Snellen chart
standardized arrangement of letters in decreasing size presented to a subject at a distance of 20 feet to test visual acuity
spasticity
increased contraction of a muscle in response to resistance, often resulting in hyperflexia
spinocerebellar tract
ascending fibers that carry proprioceptive input to the cerebellum used in maintaining balance and coordinated movement
spinocerebellum
midline region of the cerebellum known as the vermis that receives proprioceptive input from the spinal cord
stereognosis
perception of common objects placed in the hand solely on the basis of manipulation of that object in the hand
stroke
(also, cerebrovascular accident (CVA)) loss of neurological function caused by an interruption of blood flow to a region of the central nervous system
superficial reflex
reflexive contraction initiated by gentle stimulation of the skin
superior cerebellar peduncle (SCP)
white-matter tract representing output of the cerebellum to the red nucleus of the midbrain
transient ischemic attack (TIA)
temporary disruption of blood flow to the brain in which symptoms occur rapidly but last only a short time
vermis
prominent ridge along the midline of the cerebellum that is referred to as the spinocerebellum
vestibulo-ocular reflex (VOR)
reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures that images are stabilized on the retina as the head and body move
vestibulocerebellum
flocculonodular lobe of the cerebellum named for the vestibular input from the eighth cranial nerve
Weber test
use of a tuning fork to test the laterality of hearing loss by placing it at several locations on the midline of the skull
Wernicke’s area
region at the posterior end of the lateral sulcus in which speech comprehension is localized
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Dưới đây là các bài văn nằm ở bên trái. Ở bên phải là các bài luyện tập (practice) để đánh giá khả năng đọc hiểu của bạn. Sẽ khó khăn trong thời gian đầu nếu vốn từ vựng của bạn còn hạn chế, đặc biệt là từ vựng Y khoa. Hãy kiên nhẫn và đọc nhiều nhất có kể, lượng kiến thức tích tụ dần sẽ giúp bạn đọc thoải mái hơn.
The neurological exam is a clinical assessment tool used to determine what specific parts of the CNS are affected by damage or disease. It can be performed in a short time—sometimes as quickly as 5 minutes—to establish neurological function. In the emergency department, this rapid assessment can make the difference with respect to proper treatment and the extent of recovery that is possible.

The exam is a series of subtests separated into five major sections. The first of these is the mental status exam, which assesses the higher cognitive functions such as memory, orientation, and language. Then there is the cranial nerve exam, which tests the function of the 12 cranial nerves and, therefore, the central and peripheral structures associated with them. The cranial nerve exam tests the sensory and motor functions of each of the nerves, as applicable. Two major sections, the sensory exam and the motor exam, test the sensory and motor functions associated with spinal nerves. Finally, the coordination exam tests the ability to perform complex and coordinated movements. The gait exam, which is often considered a sixth major exam, specifically assesses the motor function of walking and can be considered part of the coordination exam because walking is a coordinated movement.
Localization of function is the concept that circumscribed locations are responsible for specific functions. The neurological exam highlights this relationship. For example, the cognitive functions that are assessed in the mental status exam are based on functions in the cerebrum, mostly in the cerebral cortex. Several of the subtests examine language function. Deficits in neurological function uncovered by these examinations usually point to damage to the left cerebral cortex. In the majority of individuals, language function is localized to the left hemisphere between the superior temporal lobe and the posterior frontal lobe, including the intervening connections through the inferior parietal lobe.

The five major sections of the neurological exam are related to the major regions of the CNS (Figure 1). The mental status exam assesses functions related to the cerebrum. The cranial nerve exam is for the nerves that connect to the diencephalon and brain stem (as well as the olfactory connections to the forebrain). The coordination exam and the related gait exam primarily assess the functions of the cerebellum. The motor and sensory exams are associated with the spinal cord and its connections through the spinal nerves.

Part of the power of the neurological exam is this link between structure and function. Testing the various functions represented in the exam allows an accurate estimation of where the nervous system may be damaged. Consider the patient described in the chapter introduction. In the emergency department, he is given a quick exam to find where the deficit may be localized. Knowledge of where the damage occurred will lead to the most effective therapy.

In rapid succession, he is asked to smile, raise his eyebrows, stick out his tongue, and shrug his shoulders. The doctor tests muscular strength by providing resistance against his arms and legs while he tries to lift them. With his eyes closed, he has to indicate when he feels the tip of a pen touch his legs, arms, fingers, and face. He follows the tip of a pen as the doctor moves it through the visual field and finally toward his face. A formal mental status exam is not needed at this point; the patient will demonstrate any possible deficits in that area during normal interactions with the interviewer. If cognitive or language deficits are apparent, the interviewer can pursue mental status in more depth. All of this takes place in less than 5 minutes. The patient reports that he feels pins and needles in his left arm and leg, and has trouble feeling the tip of the pen when he is touched on those limbs. This suggests a problem with the sensory systems between the spinal cord and the brain. The emergency department has a lead to follow before a CT scan is performed. He is put on aspirin therapy to limit the possibility of blood clots forming, in case the cause is an embolus—an obstruction such as a blood clot that blocks the flow of blood in an artery or vein.
Damage to the nervous system can be limited to individual structures or can be distributed across broad areas of the brain and spinal cord. Localized, limited injury to the nervous system is most often the result of circulatory problems. Neurons are very sensitive to oxygen deprivation and will start to deteriorate within 1 or 2 minutes, and permanent damage (cell death) could result within a few hours. The loss of blood flow to part of the brain is known as a stroke, or a cerebrovascular accident (CVA).

There are two main types of stroke, depending on how the blood supply is compromised: ischemic and hemorrhagic. An ischemic stroke is the loss of blood flow to an area because vessels are blocked or narrowed. This is often caused by an embolus, which may be a blood clot or fat deposit. Ischemia may also be the result of thickening of the blood vessel wall, or a drop in blood volume in the brain known as hypovolemia.

A related type of CVA is known as a transient ischemic attack (TIA), which is similar to a stroke although it does not last as long. The diagnostic definition of a stroke includes effects that last at least 24 hours. Any stroke symptoms that are resolved within a 24-hour period because of restoration of adequate blood flow are classified as a TIA.

A hemorrhagic stroke is bleeding into the brain because of a damaged blood vessel. Accumulated blood fills a region of the cranial vault and presses against the tissue in the brain (Figure 2). Physical pressure on the brain can cause the loss of function, as well as the squeezing of local arteries resulting in compromised blood flow beyond the site of the hemorrhage. As blood pools in the nervous tissue and the vasculature is damaged, the blood-brain barrier can break down and allow additional fluid to accumulate in the region, which is known as edema.

Whereas hemorrhagic stroke may involve bleeding into a large region of the CNS, such as into the deep white matter of a cerebral hemisphere, other events can cause widespread damage and loss of neurological functions. Infectious diseases can lead to loss of function throughout the CNS as components of nervous tissue, specifically astrocytes and microglia, react to the disease. Blunt force trauma, such as from a motor vehicle accident, can physically damage the CNS.

A class of disorders that affect the nervous system are the neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis (ALS), Creutzfeld–Jacob disease, multiple sclerosis (MS), and other disorders that are the result of nervous tissue degeneration. In diseases like Alzheimer’s, Parkinson’s, or ALS, neurons die; in diseases like MS, myelin is affected. Some of these disorders affect motor function, and others present with dementia. How patients with these disorders perform in the neurological exam varies, but is often broad in its effects, such as memory deficits that compromise many aspects of the mental status exam, or movement deficits that compromise aspects of the cranial nerve exam, the motor exam, or the coordination exam. The causes of these disorders are also varied. Some are the result of genetics, such as Huntington’s disease, or the result of autoimmunity, such as MS; others are not entirely understood, such as Alzheimer’s and Parkinson’s diseases. Current research suggests that many of these diseases are related in how the degeneration takes place and may be treated by common therapies.

Finally, a common cause of neurological changes is observed in developmental disorders. Whether the result of genetic factors or the environment during development, there are certain situations that result in neurological functions being different from the expected norms. Developmental disorders are difficult to define because they are caused by defects that existed in the past and disrupted the normal development of the CNS. These defects probably involve multiple environmental and genetic factors—most of the time, we don’t know what the cause is other than that it is more complex than just one factor. Furthermore, each defect on its own may not be a problem, but when several are added together, they can disrupt growth processes that are not well understand in the first place. For instance, it is possible for a stroke to damage a specific region of the brain and lead to the loss of the ability to recognize faces (prosopagnosia). The link between cell death in the fusiform gyrus and the symptom is relatively easy to understand. In contrast, similar deficits can be seen in children with the developmental disorder, autism spectrum disorder (ASD). However, these children do not lack a fusiform gyrus, nor is there any damage or defect visible to this brain region. We conclude, rather poorly, that this brain region is not connected properly to other brain regions.

Infection, trauma, and congenital disorders can all lead to significant signs, as identified through the neurological exam. It is important to differentiate between an acute event, such as stroke, and a chronic or global condition such as blunt force trauma. Responses seen in the neurological exam can help. A loss of language function observed in all its aspects is more likely a global event as opposed to a discrete loss of one function, such as not being able to say certain types of words. A concern, however, is that a specific function—such as controlling the muscles of speech—may mask other language functions. The various subtests within the mental status exam can address these finer points and help clarify the underlying cause of the neurological loss.

OpenStax. (2022). Anatomy and Physiology 2e. Rice University. Retrieved June 15, 2023. ISBN-13: 978-1-711494-06-7 (Hardcover) ISBN-13: 978-1-711494-05-0 (Paperback) ISBN-13: 978-1-951693-42-8 (Digital). License: Attribution 4.0 International (CC BY 4.0). Access for free at openstax.org.

The different regions of the CNS relate to the major sections of the neurological exam: the mental status exam, cranial nerve exam, sensory exam, motor exam, and coordination exam (including the gait exam).

(a) A hemorrhage into the tissue of the cerebrum results in a large accumulation of blood with an additional edema in the adjacent tissue. The hemorrhagic area causes the entire brain to be disfigured as suggested here by the lateral ventricles being squeezed into the opposite hemisphere. (b) A CT scan shows an intraparenchymal hemorrhage within the parietal lobe. (credit b: James Heilman)

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Script:
  1. The neurological exam is a clinical assessment tool to determine the extent of function from the nervous system.
  2. It is divided into five major sections that each deal with a specific region of the central nervous system.
  3. The mental status exam is concerned with the cerebrum and assesses higher functions such as memory, language, and emotion.
  4. The cranial nerve exam tests the functions of all of the cranial nerves and, therefore, their connections to the central nervous system through the forebrain and brain stem.
  5. The sensory and motor exams assess those functions as they relate to the spinal cord, as well as the combination of the functions in spinal reflexes.
  6. The coordination exam targets cerebellar function in coordinated movements, including those functions associated with gait.
  7. Damage to and disease of the nervous system lead to loss of function.
  8. The location of the injury will correspond to the functional loss, as suggested by the principle of localization of function.
  9. The neurological exam provides the opportunity for a clinician to determine where damage has occurred on the basis of the function that is lost.
  10. Damage from acute injuries such as strokes may result in specific functions being lost.
  11. Whereas broader effects in infection or developmental disorders may result in general losses across an entire section of the neurological exam.
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