|
Behavior
This 5-day-old infant is in the alert, quiet state. He has
spontaneous movements, which have a smooth flowing quality to them and
are not excessive, jerky or asymmetric. He seems to be attentive to the
environment. He makes attempts to organize and comfort himself by sucking
on his fists, which is a favorable behavioral response. When a bright
light is directed towards his eyes he has a definite response, which
consists of blinking and avoiding the light. With repeated stimulus there
is habituation, a diminished response to the stimulus. He responds to
sound by quieting and even turning is head and eyes toward the sound.
The above observations are the baby equivalent to the adult mental status
exam.
|
|
|
Cranial Nerves
Examination of the baby’s cranial nerve function
is often accomplished by observing spontaneous activity. During crying,
facial movement (Cranial Nerve 7) is observed for fullness or asymmetry.
The quality and strength of the cry is a way of looking at Cranial Nerves
9 and 10 function. Sucking and swallowing assesses Cranial Nerves 5,
7, 9, 10, and 12 because all of these cranial nerves are involved in
this
complex act. Eye movements (Cranial Nerves 3, 4 and 6) can be assessed
by using the vestibulo-ocular reflex (doll’s eyes maneuver). When
the head is turned, there is conjugate eye movement in the opposite direction.
Testing a baby’s behavior response to light (Cranial Nerve 2) and
sound (Cranial Nerve 8) also adds to the cranial nerve exam. Pupillary
light reflex, corneal reflex, gag reflex and funduscopic exam are done
in the same manner as the adult exam.
|
|
|
Tone - Resting Posture
For a term newborn the resting posture is flexion
of the extremities with the extremities closely adducted to the trunk.
After the first few days of life, the extremities are still predominantly
in the flexed position but they are not as tightly adducted as they are
in the first 48 hours of life.
|
|
|
Tone - Upper Extremity Tone
Assessing motor function of the upper extremities
begins with passive range of motion. This is done by rotating each extremity
at the shoulder, elbow and wrist and feeling the resistance and the range
of movement. Too little or too much resistance reflects hypotonia or
hypertonia. Further testing helps to better define tone and any tone
abnormalities.
|
|
|
Tone - Arm Traction
Arm traction is done with the baby in the supine
position. The wrist is grasped and the arm is pulled until the shoulder
is slightly off the mat. There should be some flexion maintained at the
elbow. Full extension at the elbow is seen in hypotonia.
|
|
|
Tone - Arm Recoil
Arm recoil tests tone and action of the biceps. The
arms are held in flexion against the chest for a few seconds, then are
quickly extended and released. The arms should spring back to the flexed
position. The hyotonic infant will have slow incomplete recoil. Asymmetry
to this response with lack of recoil would be seen with Erb’s or
brachial plexus palsy.
|
|
|
Tone - Scarf Sign
The tone of the shoulder girdle is assessed by taking
the baby’s hand and pulling the hand to the opposite shoulder like
a scarf. The hand should not go past the shoulder and the elbow should
not cross the midline of the chest.
|
|
|
Tone - Hand Position
A newborn
baby’s hand is held in a fisted position with the fingers flexed
over the thumb. The hand should open intermittently and should not always
be held in a tight fisted position. Rubbing the ulnar aspect of the hand
or touching the dorsum of the hand will often cause extension of the fingers.
Over the first 1 to 2 months of life, the baby’s hand becomes more
open. Persistence of a fisted hand is a sign of an upper motor neuron lesion
in an infant.
|
|
|
Tone - Lower Extremity Tone
Assessing motor function of the lower extremities
begins with passive range of motion. This is done by flexing the hips,
then abducting and adducting the hips. Next, flex and extend the hips,
the knees and ankles. Further testing helps to better define the tone
and any tone abnormalities.
|
|
|
Tone - Leg Traction
Leg traction is done by holding the leg by the ankle.
The leg is pulled upward until the buttock starts to be lifted off the
mat. The knee should maintain a flexed angle. Full extension of the knee
with little resistance to pulling on the leg is a sign of hypotonia.
|
|
|
Tone - Leg Recoil
To test leg recoil, the legs are fully flexed on the
abdomen for a few seconds, then the legs are quickly extended and released.
The legs should spring back to the flexed position. Legs that remain
extended could be due to either hypotonia or abnormal extensor tone.
|
|
|
Tone - Popliteal Angle
The popliteal angle is an assessment of the tone
of the hamstring muscles. It is done one leg at a time. The thigh is
flexed on the abdomen with one hand and then the other hand straightens
the leg by pushing on the back of the ankle until there is firm resistance
to the movement. The angle between the thigh and the leg is typically
about 90 degrees. Extension of the leg beyond 90 to 120 degrees would
be seen in hypotonia.
|
|
|
Tone - Heel to Ear
Holding the baby’s foot in one hand, draw the
leg towards the ear to see how much resistance there is to the maneuver.
The foot should go to about the level of the chest or shoulder, but not
all the way to the ear. If the foot can be drawn to the ear then there
is hypotonia.
|
|
|
Tone - Neck Tone
The tone of the neck can be assessed by passively rotating
the head towards the shoulder. The chin should be able to rotate to the
shoulder but not beyond the shoulder. If the chin goes beyond the shoulder
then there is hypotonia of the neck muscles, which is associated with
poor head control.
|
|
|
Tone - Head Lag
Starting in the supine position, the baby is pulled by
the arms to the sitting position. The head and the arms are observed
during the maneuver. The arms should remain partially flexed at the elbow
and the head may lag behind the trunk, but should not be fully flexed
backwards. When the baby is in the sitting position, the head should
be able to come to the upright position for at least a few seconds before
dropping forward or backward.
|
|
|
Tone - Head Control
The strength and tone of the neck extensors can be
tested by having the baby in sitting position and neck flexed so the
baby’s chin is on the chest. The baby should be able to bring the
head to the upright position. The neck flexors can be tested by having
the head in extension while in the sitting position. The baby should
be able to bring the head to the upright position. These tests are an
extension of the test for head lag and are done at the same time.
|
|
|
Positions - Prone
In the prone position, the baby should be able to extend
the neck to the point where the head can be turned side to side. When
the arms are extended by the side of the trunk, the baby should be able
to bring them forward into a flexed position. The buttock should be somewhat
elevated because the hips are flexed and adducted. A baby that is flat
on the mat and can’t turn the head back and forth has low tone
and weakness.
|
|
|
Positions - Ventral Suspension
The baby is placed in the prone position,
suspended in the air by the hand placed under the chest. The baby’s
head position, back and extremities are observed. The head should stay
in the same plane as the back. The back should show some resistance to
gravity and not be simply draped over the hand on the chest. The extremities
should maintain some flexion tone and not dangle in extension. Ventral
suspension is a very good way to assess a baby’s neck and trunk
tone.
|
|
|
Positions - Vertical Suspension
The examiner holds the baby in the upright
position with feet off the ground by placing the hands under the arms
and around the chest. The baby should be suspended in this position without
slipping through the hands of the examiner. If there is shoulder girdle
weakness the arms will extend upwards and the examiner will have to reposition
their grasp of the baby to avoid the baby slipping through their hands.
It feels like trying to hold on to a slippery fish.
|
|
|
Reflexes - Deep Tendon Reflexes
Testing deep tendon reflexes is an important
part of the newborn neurological exam. They can be technically difficult
to do. The first thing is to use a reflex hammer, not a finger or a stethoscope.
Ideally, the baby is in a quiet alert state with the head in the midline.
The head turned to one side can reinforce the tone and reflexes on that
side. I usually start with the knee jerk because is the easiest to obtain.
Take control of the leg with the hand under the knee and the leg at about
a 90 degree angle at the knee. Then strike the patellar tendon with the
reflex hammer using a pendular action rather a chopping action.
Reposition
the leg and try several times if you have trouble getting a knee jerk.
Next, I go to the ankle jerk. If I can’t get an ankle jerk in
the conventional fashion, I place my fingertips on the plantar aspect
of
the foot, flex the foot slightly, then strike the back of my fingers.
For the bicep jerk, have the arm flexed at the elbow, thumb over the
bicep tendon, then strike the thumb with a pendular action. Because of
the predominantly flexor tone of the newborn, it is rare to obtain a
triceps jerk.
Absence of deep tendon reflexes is a much more important
finding than hyperreflexia in the newborn. A normal newborn can have
hyperreflexia and still be normal, if the tone is normal, but absent
reflexes associated with low tone and weakness is consistent with a
lower motor neuron disorder. Preserved or exaggerated reflexes associated
with
low tone is the hallmark of what is called central or cerebral hypotonia
and the cause is an upper motor neuron lesion.
|
|
|
Reflexes - Plantar Reflex
The normal response to stroking the lateral
aspect of the plantar surface of the foot is extension of the great toe
and fanning of the other toes. If the stimulus is brought across the
ball of the foot then a grasp reflex will be elicited and the toes will
plantar flex. The up going toes or “Babinski sign” is normal
in the infant and may be present for the first year of life because of
the incomplete myelination of the corticospinal tracts.
|
|
|
Primitive Reflexes - Suck, Root
The baby should have a strong coordinated
suck reflex with good stripping action of the tongue. There should be
resistance to pulling out the pacifier. A root reflex is obtained by
gently stroking
the cheek towards the lips. The baby should open the mouth towards the
stimulus and turn the head to latch on to the object.
|
|
|
Primitive Reflexes - Moro
The Moro reflex is obtained by holding the
baby’s head and shoulders off of the mat with the arms held in
flexion on the chest. The examiner suddenly lets the head and shoulders
drop back a few inches while releasing the arms. The arms should fully
abduct and extend, then return towards the midline with the hand open
and the thumb and the index finger forming a “C” shape. An
absent or incomplete Moro is seen in upper motor neuron lesions. An asymmetric
Moro is most often seen with a brachial plexus lesion. The brachial plexus
palsy is on the side of the poorly abducted arm.
|
|
|
Primitive Reflexes - Galant
The Galant reflex (trunk incurvation) is
obtained by placing the baby in ventral suspension, then stroking the
skin on one side of the back. The baby’s trunk and hips should
swing towards the side of the stimulus.
|
|
|
Primitive Reflexes - Stepping
The stepping or walking reflex is obtained
by holding the baby upright over the mat with the sole of the foot touching
the mat. This initiates a reciprocal flexion and extension of the legs
and it looks like the baby is walking.
|
|
|
Primitive Reflexes - Grasp
Placement of the examiner’s finger in
the palm of the hand or on the sole of the foot will cause flexion and
grasping of the fingers or toes. One should avoid touching the dorsum
of the hand while eliciting the grasp reflex because stimulating the
back
of the hand causes a hand opening reflex to occur. With the two competing
reflexes, the grasp response will be incomplete or inconsistent.
You can actually see this happen with the baby that is being examined.
The
grasp reflex can be reinforced by applying traction on the arm.
|
|
|
Head Shape and Sutures
The head should be closely inspected as part
of the neurological examination. There can be molding of the head, which
is an expected finding in a newborn. Palpate the sutures and outline
the anterior and posterior fontanelles.
|
|
|
Head Circumference
It is very important to measure the head circumference,
which sometimes is referred to as the OFC (occipital-frontal circumference)
because the measurement is obtained by placing the measuring tape around
the most prominent aspect of the frontal and occipital bones. The most
accurate measurements are obtained with a plastic tape measure rather
than a paper tape measure because the paper can stretch. The head circumference
measurement should be plotted on a standardized head growth chart for
the appropriate sex.
|
|