Clinical application for Somatosensation Flashcards
What is the purpose of a sensory exams? (cover conscious relay pathways)
establish whether sensory impairment is present and, if so, the location, type of sensation affected, and severity of the deficit
What are the 6 guidelines to improve the reliability of sensory testing?
- Administer tests in a quiet, distraction-free setting.
- Position the patient seated or lying supported by a firm, stable surface to avoid challenging balance.
- Explain the purpose of the test.
- Demonstrate each test before administering.
- Block the patient’s vision during the tests.
- Apply stimuli near the center of the dermatomes being tested.
What does the quick screening for somatosensation include?
- Testing proprioception and vibration in the fingers and toes
- Testing fast pain sensation in the limbs, trunk, and face with a pinprick
What distribution of losses would be seen in a stroke or neuropathy?
body region
What distribution of losses would be seen in a nerve root or spinal cord injury?
Dermatome
What distribution of losses would be seen in a peripheral nerve injury?
Peripheral nerve distribution
What are the two methods for electrodiagnostic studies?
- Nerve conduction study
2. Somatosensory-evoked potentials
Measures peripheral nerve function; Stimulating in the periphery and recording in the periphery; surface recording electrodes are placed along the course of a peripheral nerve, and the nerve is electrically stimulated
Nerve conduction study (NCS)
Tests peripheral nerves and CNS pathways; Stimulating in the periphery and recording in the CNS
Somatosensory-evoked potentials
What type of nerves are you looking at when doing a NCS?Why are they performed?
Large-diameter fibers; to see if there is a loss of myelination
To determine if an NCS is normal, what three numerical values are compared?
- Distal latency
- Amplitude of the evoked potential - measure of how many axons carry a signal
- Conduction velocity- measure of myelination
What test would you use to localize a peripheral nerve problem (myelination, or compression due to carpal tunnel)?
Nerve Conduction Study
Evaluate the function of the pathway from the periphery to the upper spinal cord or to the cerebral cortex; Potentials are used to verify subtle signs and locate lesions of the dorsal roots, posterior columns, and brainstem
Somatosensory-Evoked potentials
What are the three types of ataxia?
- Sensory
- Vestibular
- Cerebellar
Test that is used to distinguish between cerebellar ataxia and sensory ataxia. How do you distinguish between sensory and cerebellar ataxia?
Romberg test
- cerebellar = unable to perform with eyes open or closed
- sensory = can perform with eyes open, but not closed
What three systems are there to maintain balance?
- Visual
- Vestibular
- Proprioception (sensory)
general term for dysfunction or the pathologic condition of one or more peripheral nerves
neuropathy
What will be there result of a severance of a peripheral nerve?
- Lack of sensation in the distribution of the nerve (pain, touch, proprioception)
- Pain may occur (can’t feel stimuli but changes occurring cause pain or tingling in a body part)
- Sensory changes are accompanied by motor and reflex loss
What is the order of sensory losses that proceed pressure, compression or injury?
Starts with the fastest axons and goes to the slowest:
- Conscious proprioception and discriminative touch
- Cold
- Fast pain
- Heat
- Slow pain
What are common causes of dysfunction in spinal region?
- Trauma to the spinal cord and complete or partial severing of the cord
- Disease that compromises the function of specific areas in the spinal cord
- Virus that infects the dorsal root ganglion
Lesion that results in:
All sensation is prevented at one or two levels below the lesion; Voluntary motor control below the lesion is also lost
Transection of the cord