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Light Touch
With light touch the patient indicates that the perception of the stimulus
is different over the left side of the face. The feeling has an abnormal
quality to it described as different, uncomfortable or burning. This would
be called paresthesia or dysesthesia. Light touch causing
pain would be allodynia.
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Pain Upper
Extremities
A sharp
wooden stick is used to delineate the area of decreased sharp sensation.
There is loss over the ulnar side of the right hand as well as the ulnar
aspect of the forearm but the arm is normal. This loss is constant with
a C8-T1 dermatome distribution.
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Pain Lower
Extremities
This patient has a sensory level at T3 with decreased pain sensation below
the level including the leg. The sensory level is one to two spinal cord
segment levels below the actual anatomical cord lesion because the spinothalamic
axons ascend several spinal cord levels prior to crossing. The left sided
T3 sensory level combined with this patient's upper extremity sensory
finding indicates a lesion of the right side of the spinal cord at the
C8-T1 level.
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Temperature
The patient
is unable to distinguish the difference between a hot and cold test tube
simultaneously applied to the ulnar side of the right hand and arm and
the left leg. This deficit is in the same distribution as the pain deficit
noted when testing sharp sensation. Pain and temperature sensation are
tests for spinothalamic tract function.
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Vibratory
Vibratory
sensation is decreased on the right great toe compared to the left. This
could be due to a peripheral neuropathy but it also could be secondary
to DCML deficit, which is actually the case for this patient.
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Position Sense
The patient
makes more mistakes identifying the correct direction of toe movement
on the right then left indicating a proprioceptive loss. For this patient
this is secondary to a lesion effecting the dorsal column on the right
side of the spinal cord.
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Tactile Movement
When comparing
left vs. right, the patient has more difficulty on the right side again
indicating dorsal column dysfunction. If the dorsal column pathways are
intact, then tactile movement is a sensitive test of parietal cortical
function.
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Two-Point Discrimination
Patients with a lesion of the primary somatosensory cortex will have difficulty
with two-point discrimination on the opposite side of the body. The peripheral
nerve and DCML pathway must be intact for this test to be a test of parietal
cortical function.
No video is available.
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Graphesthesia
This patient has more difficulty identifying numbers written in the right
hand than in the left hand. This is called agraphesthesia and is from
a lesion of the somatosensory cortex in the left parietal lobe.
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Stereognosis
The patient is asked to identify objects placed in both the right and
left hand with his eyes closed. He knows that something is in his right
hand but he is unable to identify it while he readily identifies the same
object placed in the left hand. This is called astereognosis. The patient
has a lesion involving the left parietal lobe.
Video is without sound.
Video is courtesy of Alejandro Stern, Stern Foundation.
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Double Simultaneous
Stimulation
When the
patient is touched on the right or left he correctly identifies the side
touched but when both sides are touched simultaneously he neglects the
stimulus on the right. This is extinction or simultanagnosia and indicates
a lesion in his left parietal cortex.
Video is without sound.
Video is courtesy of Alejandro Stern, Stern Foundation.
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Romberg Test
With his
eyes open, the patient is able to hold still but when his eyes are closed
he sways and loses his balance. He has a significant loss of proprioception.
Video is without sound.
Video is courtesy of Alejandro Stern, Stern Foundation.
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