The SSEP, or Somatosensory Evoked Potential, test is a neurophysiological diagnostic procedure used to evaluate the function of the sensory pathways in the body. It assesses how well sensory signals travel from the peripheral nerves in the arms and legs, through the spinal cord, to the brain.
How the SSEP Test Works
The test involves stimulating peripheral nerves (typically in the arms or legs) with electrical impulses. Electrodes placed on the skin record the electrical responses as these signals travel along the nerve pathways to the brain. These responses are then analyzed to identify any abnormalities in the transmission of sensory signals.
What the SSEP Test Detects
The SSEP test helps detect a variety of neurological problems, including:
- Spinal cord injuries: The test can pinpoint the location and severity of damage to the spinal cord.
- Neuromuscular diseases: Conditions affecting the nerves and muscles can be diagnosed or monitored.
- Multiple sclerosis (MS): SSEPs help assess the integrity of sensory pathways frequently affected by MS.
- Peripheral neuropathy: Damage to peripheral nerves can be detected.
- Other neurological conditions: The SSEP can assist in the diagnosis of other neurological disorders impacting sensory function.
Understanding the Results
A neurologist interprets the results of the SSEP, comparing the recorded responses to established norms. Delays or abnormalities in the signals can indicate nerve damage or dysfunction at specific points along the sensory pathways. The location and nature of these abnormalities help pinpoint the cause of neurological symptoms.
For example, a delayed response might suggest a lesion in the spinal cord. Absence of a response could indicate severe nerve damage.
SSEP Test Variations
While the core principle remains the same, the specific stimulation sites and electrode placement can vary depending on the clinical question. The test can be tailored to focus on specific areas of the body and nervous system.
For instance, it could concentrate on the upper extremities to evaluate arm sensation, or focus on the lower extremities to assess leg function.
