Neurological Examination of Sensation, Reflexes, and Motor Function Flashcards
Type of primary sensation that refers to external stimuli, typically light touch, pain, and temperature, detected by various receptors in the skin
Exteroceptive sensation
Type of primary sensation that refers to stimuli from muscles, tendons, ligaments, and joints, in relation to position and movement of the body, limbs, and digits, and is important for balance and coordination
Proprioceptive sensation
Type of primary sensation that refers to internal stimuli affecting visceral organs, such as perception of a distended bladder
Interoceptive
Type of sensation that involves the simultaneous perception of several basic stimuli, further integrated and interpreted at the cortical level
Cortical (combined) sensation
Abnormal, spontaneous sensation, not provoked by stimuli, often described as tingling or “pins and needles”
Paresthesia
Uncomfortable, at times painful, hypersensitivity to non-noxious stimuli
Dysesthesia
What are the components of the exteroceptive sensation examination?
- Light touch (wisp of cotton, light stroke of the finger)
- Pain (broken cotton-swab stick, blunted safety pin)
- Temperature (cool metallic object)
- Vibration (128 Hz tuning fork), patient reports when the vibration is gone
- Alternate from left to right
- Move proximally
Define abnormally decreased vibration sensation.
If the tuning fork is still perceived to vibrate more proximally or at the same bony site (less valid with age, as this normally declines)
What are the components of the examination of proprioceptive sensation?
Test position sense by raising or lowering the patient’s finger or toe subtly a few degree at one joint; patient identifies the movement as “up” or “down”
If patient detects only large excursion of the joint, but consistently misses smaller movements, position sense is decreased. If even large joint movements are not detected, position sense is absent. May test proximally at wrists and ankles.
What is gnosis?
Object recognition
A lesion in the ___ or its connecting pathways produces a cortical sensory deficit in the contralateral body, while primary sensations may be relatively intact.
Parietal sensory cortex
What is the tactile recognition of familiar or common objects, such as a penny or paper clip in the palm of the hand, with the patient’s eyes closed?
Sterognosis
What is a deficit in stereognosis?
Astereognosis
What is the identification of numbers traced on the palm with the eyes closed?
Graphesthesia
What is a deficit of graphesthesia?
Agraphesthesia
What is the ability to perceive two tactile stimuli applied simultaneously to the same bilateral parts of the body with the eyes closed?
Double simultaneous stimulation
When bilateral tactile stimuli are given, the consistent failure to detect a stimulus on one side is due to what lesion? What is this called?
Contralateral parietal cortical lesion; extinction on double simultaneous stimulation
What is the ability to detect the simultaneous application of two sharp points separated by a minimal distance on the skin?
Two-point discrimination (fine touch)
How does a deficit in two-point discrimination appear?
Perceiving the two points as one point or failing to feel it at all
Although conveyed by the ___, two-point discrimination is usually considered a cortical sensation.
Posterior columns
Describe the progression of sensory loss in disorders of peripheral nerves.
Initial involvement of the larger, more myelinated sensory fibers causes impairment of position sense and vibration
Initial involvement of the smaller, less myelinated or unmyelinated sensory fibers produces early impairment of temperature and pain sensation
Eventually, if extensive and severe, all fibers and sensory modalities will be impaired.
Lesions of the posterior or dorsal columns cause what sensory deficits?
Deficits in position sense, vibration, and two-point discrimination
Presentation of lesions in the posterior (dorsal) columns of the spinal cord?
Deficits in position sense, vibration, and two-point descrimination
Isolated deficits in two-point discrimination associated with?
Contralateral sensory (parietal) cortex lesion
Lesions of the spinothalamic tract cause what deficits?
Deficits in pain and temperature
Absence of light touch sensation associated with?
Extensive lesions of the spinal cord or its dorsal roots (or in severe peripheral neuropathy or thalamic lesions) - because multiple spinal cord pathways convey light touch
Define mononeuropathy.
Sensation is decreased or lost in the territory of one peripheral nerve
Define polyneuropathy.
Aka peripheral neuropathy, sensation is decreased or lost in several peripheral nerves, creating a “stocking and glove” distal pattern of deficit
What are sensory impairments in the territory of one or more dermatomes from one or multiple root lesions.
Dermatomal deficits
Dissociation of sensation (loss of one modality with preservation of another) is characteristic of what type of lesion? Note that it is possible to occur in ___ lesions.
Spinal cord lesions (myelopathy); brain stem lesions
Define an intramedullary spinal cord lesion and describe the associated deficits.
Occur within the spinal cord parenchyma; cause a suspended or vestlike sensory loss and sacral sparing of sensory deficit
Define an extramedullary spinal cord lesion and describe the associated deficits.
Compress the spinal cord from outside, creating an initial sensory loss in sacral segments, progressing up “to a level” because of lamination of the STT
Hemisensory (hemibody) deficit of basic sensations on the R or L side of the body including the face is caused by what lesions?
Contralateral thalamic lesion or involvement of sensory pathways to the contralateral parietal lobe
Isolated or predominant deficits involving cortical or combined sensation typically occur on one side of the body and are usually do to what lesion?
Lesion in the contralateral parietal sensory cortex
Important dermatomal landmarks - C5
Lateral shoulder
Important dermatomal landmarks - C6
Thumb
Important dermatomal landmarks - C7
Index/middle fingers
Important dermatomal landmarks - C8, T1
Ring/little fingers
Important dermatomal landmarks - T4
Nipple
Important dermatomal landmarks - T10
Umbilicus
Important dermatomal landmarks - L3, L4
Anterior thigh
Important dermatomal landmarks - L5
Dorsal foot
Important dermatomal landmarks - S1
Lateral foot/sole
What is referred pain?
Pain perceived along a dermatome having sensory afferents from the same dorsal root level as the diseased internal organ