MTBI-Introduction

This presentation addresses how the Emergency Physician should conduct the neurologic exam in stroke. This exam will be used to
answer the following questions:

One of the most daunting aspects of the medical examination for the Emergency Physician and the primary care provider is the normal
neurological exam. Most of us feel inclined to do an abbreviated survey because the complexity of the neurological exam is greater
than that of any other organ system. Many chapters, books and articles have been devoted to the topic of the neurological exam, but this
module is dedicated to those physicians who not only need to perform a screening neurological examination but also those who have to
teach other medical providers the basics of completing such an exam.

The underlying focus of this module is to help physicians identify, diagnose and participate in the management of the patient with an
acute stroke. In this review, basic neuroanatomy will be covered as well as the required history and physical skills required to make a
diagnosis in a time sensitive manner.

Neuroanatomy

The central nervous system can be divided very simply into several discrete compartments. One can be criticized for oversimplification
when it comes to the nervous system, but an operational compartmentalization is often helpful when it comes to managing patients
with a neurological complaint.

The nervous system can be divided into the peripheral and central nervous systems. The peripheral nervous system contains the
peripheral nerves. The central nervous system can be thought of as a neuroaxis consisting of the

In gross anatomical terms, the brain (cortex and subcortex) region can be considered the supratentorial region. (Not to be confused
with the common medical term often associated with patients who exaggerate or embellish symptoms that have no organic basis.)
The infratentorial region consists of the cerebellum and brainstem. See Figure 1.

Supratentorium

Infratentorium

The cortex functionally is responsible for several activities. Among its most famous activities are consciousness, speech, motor and
sensory functions – in essence, the cortex is the higher functioning command center.

The subcortex contains the internal capsule, basal ganglia and the thalamus. The subcortex can be considered a relay station
for the higher command station and the lower distribution pathway of the spinal cord. The internal capsule directly relays motor and
sensory function, the basal ganglia is responsible for the fine adjustment of movements, and the thalamus is the sensory relay point.

The cerebellum, in conjunction with the basal ganglia helps to refine motor activity.

The brainstem contains the origin of the cranial nerves and contains the primitive functions of living – the breathing center, vasomotor
center, and modulates the interaction between the cerebellum and the rest of the neuroaxis.

The spinal cord is divided into three basic columns – anterior, posterior and lateral. The anterior column is primarily responsible
for motor function, the posterior column is primarily responsible for sensory (proprioception) function and the lateral column has an
ascending sensory tract (pain and temperature) and a descending motor tract.

The General Approach

Any patient who requires a neurological evaluation should have a complete history and physical examination performed. After a careful
general history and physical exam, a neurological review of systems should be performed. This includes a review of basic neurological
functions. The importance of the general physical examination can not be emphasized enough. Diseases of virtually every organ system
will eventually have neurological sequelae. Similarly, the history and review of systems need to be reviewed as well. The subsequent
neurological exam is used more to rule in or out the possibilities of a neurological problem.

Table 1 includes a brief summary of the neurological functions and includes the minimum question for each function.

Once the review of systems is complete, a focused neurological examination should ensue, followed by localization and key interventions.
The neuro exam has five components – 1)mental status 2)cranial nerves 3)motor and reflexes 4)sensory 5)coordination and gait.
Several neurological scales can be very helpful in completing a focused, yet effective neurological evaluation. These include the Glasgow
Coma Scale, the MiniMental Status Examination and the NIH stroke scale, as well as the prehospital LA stroke scale and the Cincinnati
Stroke scale.

The nice thing about the neurologic exam is that the examiner can rapidly localize the lesion once an abnormality is detected by history and
confirmed by the physical examination.

To properly assess mental status, four basic areas need to be addressed. First, the GCS score is often used to establish a baseline
level of consciousness. However, it has limitations. It is not helpful in non-traumatic processes and must be reassessed serially to be
useful (see table 3). The patient’s orientation to person, place and time should also be determined. When questioning a patient to
determine orientation, one should start with the more general questions and work towards the specifics. When it comes to person,
most people know who they are, what is more helpful is for the patient to identify who has accompanied them.

The second area to assess is concentration and attention. Patients should be asked to perform serial seven subtraction, that
is count backwards from 100 decreasing by seven each time. Drawing a clock face, a higher cognitive function, is a combination
of visual-spatial capability and concentration. Alternatively, the patient can be asked to spell words forwards and backwards, such as
WORLD and TABLE. For patients with limited education, making change is an effective diagnostic task, such as “how many quarters
in $1.75.”

The third area to assess is language and can be performed quickly. Listen to the fluency of the patient’s speech, testing for
comprehension of simple commands such as repetition of words, naming of objects, writing a sentence and reading a phrase.

Memory should be tested regarding immediate, recent and remote events. A traditional method of doing so is asking the patient
to repeat three separate items, and then ask them to recall them after one minute and after five minutes. A remote event would be
asking the patient their date of birth, or birth of their children or some other personal event.

Testing for mental status reveals a great deal about how the cortex is functioning. The cortex can be thought of as having several
different areas, the frontal, parietal, temporal and the occipital. The mental status exam attempts to assess the function each of
these areas. See table 2 for a description of what each area does in terms of mental status. Finally the Mini Mental Status
examination is a convenient way to assess cortical function. Though originally designed to test patients with Alzheimer’s disease
and other dementia’s, is does help the examiner get a quick assessment of cortical function.

The cranial nerve examination is an excellent way to localize a brainstem lesion. Most cranial nerves originate in the brainstem,
because their nucleus resides there. It should be noted that their supranuclear tract descends from the cortex, once again
demonstrating that the cortex has the highest command center. The supranuclear tract comes from the cortex and crosses before
it gets to the nucleus of the cranial nerve. So a lesion in the cortex will cause a contralateral deficit of the cranial nerve while an
infranuclear lesion will cause an ipsilateral deficit.

Most of the cranial nerves are lumped into three areas of the brainstem, all except CNI and CNII, who have escaped the
infratentorium and reside in the supratentorium. Although this is not entirely anatomically correct, CN III and IV are located
in the midbrain, CN V-VII are in the pons and CN VIII- XII are in the medulla.

Motor function is controlled by the cortex. It begins in the upper motor neurons (the Betz cells of the precentral gyrus).
The axons project via the posterior limb of the internal capsule (part of the subcortex), travel through the brainstem (the pyramidal
tract), cross in the lower medulla, then descend in the spinal cord (corticalspinal tract within the lateral column) to the lower motor
neurons in the spinal cord. See figure 4

The lower motor neuron originates from the anterior column of the spinal cord and ends in the motor end plate. (Somehow the
anterior column of the spinal cord communicates with the lateral column.) The distinction between an upper motor and lower motor
neuron is important because a lesion in either of the pathways gives markedly different clinical presentation.

The standard motor examination should include five areas, strength, tone, posture, involuntary movements and reflexes.
A rating scale for motor examination is important for two reasons. Identifying motor deficits allows for localization (ie which side
of the brain is involved). With the rating of the motor deficits one can follow progression or improvement that has important
prognostic implications.

Muscular bulk and tone will help in differentiating between upper and lower motor neuron deficits. There are two major postures
that are important to note – decorticate and decerebrate. Both are upper motor neuron problems. Decorticate posturing suggests
a supratentorial pathology whereas decerebrate posturing indicates an infratentorial pathology. Because the lesion goes deeper in
the brainstem, decerebrate posturing has a worse prognosis. Decorticate posturing is extension of the lower extremities and flexion
of the upper extremities whereas decerebrate rigidity is extension and internal rotation of all extremities.

Involuntary movements indicate involvement of the extra-pyramidal system, which includes complicated neuronal tracts between the
basal ganglia and cerebellum. (pyramidal tract =cortex and internal capsule tracts).

Reflexes are important to note because they give information about the upper motor neuron verses lower motor neuron lesions and
lateralization. (Symmetric verses asymmetric indicating systemic or metabolic verses isolated neurological pathology.)

The presence of an abnormal reflex such as the Babinski reflex (toe fanning and upward big toe movement upon stimulation of the
lateral aspect of the sole from heel to big toe) is important to note. Either a patient has an abnormal reflex, the Babinski reflex, or
there is a normal plantar response, downgoing toe. The presence of a Babinski indicates an upper motor lesion.

Sensory examination is often difficult because it is a very subjective examination. With an uncooperative patient the sensory exam
may be impossible to perform accurately. But when it can be done, the sensory exam will reveal information about where lesions are
located.

Sensations are transmitted from the peripheral nerves to the spinal cord. Once in the spinal cord, the nerve transmissions ascend
through several tracts or columns. Pain and temperature are located in the lateral column and decussate (cross to the other side)
at the level of entry. Proprioception and vibration travels through the posterior columns and decussate at the level of the brainstem.
Touch travels through both the lateral and posterior columns, proving that the body has redundant systems for important functions.

Once the nerve impulses leave the spinal cord, they enter the brainstem via the posterior horn of the internal capsule through the
thalamus on the way to the post central gyrus of the cortex. Along the way they send information, via collaterals, to the cerebellum
and the thalamus.

Coordination and gait require the integration of several parts of the nervous system, and essentially assess all of the areas
mentioned. Together, coordination and gait can be thought of as the “final exam of the nervous system”. Many patients deemed
“non-focal and intact” have an exam limited to the gurney. When asked to walk, these patients reveal significant dysfunction.
The classic neurologic abnormality indicating cerebellar dysfunction is the presence of ataxia, which can be in the upper extremities,
the lower extremities or in the trunk. Ataxia is manifested by a lack of smooth movements and loss of coordinated movement.
Gait must be checked and any gait ataxia must be differentiated from motor weakness.

Coordination and gait is an integration of multiple tracts including the pyramidal, extrapyramidal, posterior columns and cerebellar
tracts. The most important finding for cerebellar function is the presence of ataxia, which can be in the upper extremities, the lower
extremities or in the trunk. Ataxia is manifested by a lack of smooth movements. Gait must be checked and any gait ataxia must be
differentiated from motor weakness.

A useful tool in the rapid evaluation of a patient with a suspected neurologic problem is the NIH Stroke Scale. It incorporates many
of the elements of the neurologic exam discussed, yet condenses them into a quick assessment scale.

Localization

Knowing where the lesion is not just an intellectual exercise to be completed by the examiner to prove that they know their neuroanatomy.
Where a lesion resides has important implications in terms of diagnostic and therapeutic interventions. It is helpful to consider the four
major areas of the neuroaxis:

A. Cortex Lesions

1. Dysphasia – any disorder of language which includes expressive, receptive, global aphasia, naming and reading.

2. Cortical Sensory loss- which includes an inability to identify objects in your hand (stereognosis), loss of two
point discrimination and the inability to discern writing on one’s palm. (graphesthesia)

3. Face and extremity weakness with possible paresthesia – It is important to note whether the arm is
involved more than the leg. If the arm is more involved, the lesion is in the middle cerebral artery territory. If the leg
is more involved, then it is anterior cerebral artery territory.

a. Note: Both the face and extremity involvement will be on the same side because the upper motor neuron fibers
have crossed together at the level of the brainstem. The lesion is higher than the brainstem.

4. Conjugate Gaze Palsy – There are three gaze centers, two reside in the cortex and one in the brainstem.
The major one is the frontal cortex gaze center. So if the eyes deviate together at all, the most likely lesion is in the
frontal cortex.

a. The eyes will deviate toward the cortical lesion, because the right frontal gaze center is responsible for looking
to the left and vice versa. So when the right frontal cortex gaze center is knocked out, the conjugate gaze will be
toward the right.

5. Seizures – Seizures associated with hemiplegia are most likely due to a cortical lesion. Seizures generally originate in the cortex.

B. Subcortical Lesions – internal capsule, basal ganglia and thalamus

1. Visual Field Defect – When a patient has difficulty with detecting simultaneous movements in certain visual fields, the
lesion is likely to be in the cortex or the subcortical area. For example presence of the left homonymous hemianopsia indicates a
subcortical lesion in the visual pathway.

2. Dystonic postures – Unusual, uncoordinated movements such as choreoathetosis (involuntary jerky movements),
hemiballismus (slow, bizarre movements of half the body), or simply a loss of harmony of refined movements are indicative of basal
ganglia lesions. Remember that the basal ganglia helps modulate movement, and refines the motor activity of the pyramidal system.

3. Face and extremity weakness – When the face, arm and leg are equally involved then the lesion must reside in the
internal capsule.

4. Dense Sensory Loss – Loss of pain and touch in face and extremities signifies a lesion in the thalamic area. The
thalamus is a sensory relay point as well as a primary receptive center, so a lesion there will affect the sensation in the face
and extremities.

C. Brainstem Lesions – midbrain, pons and medulla, and cerebellum

Lesions in the brainstem result in a crossed finding.

1. Crossed Hemiplegia - The cranial nerves will be affected on one side, while the extremity motor deficits are on the other side.
This brainstem lesion will affect the infranuclear cranial nerves ipsilaterally, and the motor tract contralaterally, because the motor tract
decussates (crosses) just above the spinal cord.

3. Nystagmus - The medial longitudinal fasciculus helps to coordinate eye movement and resides in the brainstem axis. It
connects the two nuclei of CNIII and CNVI which allow conjugate gaze to occur. A problem in the brainstem could result in MLF
malfunction that would yield nystagmus. The nystagmus could be horizontal, vertical or rotary.

4. Lower Cranial Nerve findings - Cranial nerves VIII –XII project from the lower brainstem. Thus lesions in this area will cause
hearing loss and vertigo (CNVIII), dysarthria (difficulty with articulation), dysphagia (CN IX-X) (difficulty with swallowing), and tongue
deviation (XII).

D. Spinal Cord Lesions

Lesions in the spinal cord cause predictable deficits. Assuming normal cortical, subcortical and brainstem functions, the findings
are listed below.

2. Motor deficits can be monoplegic (one extremity), paraplegic (both lower extremities), hemiplegia (one side of
the body) or quadriplegic (four extremities). In the case of monoplegia or hemiplegia, the lesion will be ipsilateral.

3. Sensory finding will be contralateral because pain and temperature fibers cross immediately after entering
the cord.

Dominance

The controlling hemisphere in most human beings is the left side of the brain. The dominant hemisphere really controls most things in
the body. Neurologists like to know whether a patient is right-handed or left-handed. Right-handed people are left hemisphere
dominant. Most left handed people are also left hemisphere dominant except for about 10% which will be right hemisphere dominant.

The reason dominance is so important is that a stroke in a dominant hemisphere for the same sized lesion can be more devastating.
The complexity of function in the dominant hemisphere should not be underestimated. The speech centers are located in the
cortex of the dominant hemisphere. Aphasia does not occur when the nondominant hemisphere is involved.

When the nondominant hemisphere is involved, the following symptomatology results:

1. Inattention and Denial – These patients neglect the left side of the body despite having significant deficits.
These patients will not see you if you stand on their left. They may not shave the left side of their face. They remain
unconcerned about their deficits, because they do not believe they have any.

2. Constructional Apraxia – Patients are unable to do a motor task without having a motor deficit. They just
won’t be able to do it. They may not be able to open the door even though they have the motor capability to do so.

3. Spatial Disorientation – Patients are able to get lost in their own home.

Stroke (Ischemic Cerebrovascular Disease)

Cerebral ischemia is caused by a reduction of blood flow that may be transient or lead to infarction. Strokes are clinical
syndromes with different etiologies and different symptom complexes.

Lacunar infarcts are small areas of thrombotic infarct in the brain that are usually the result of hypertension or a complication
of diabetes mellitus. They are often found in the basal ganglia and the pons.

The Focused Neurologic Exam in Stroke