Diagnosis of Neuropathy
It is important to determine the cause of the neuropathy as quickly as possible to reduce the risk for permanent nerve damage. Diagnosis of neuropathy involves physical and neurological examination, nerve conduction velocity studies (NCV), and electromyography (EMG).
Nerve conduction velocity studies record the speed at which impulses travel through nerves and measure electrical responses. EMG records electrical activity in muscle tissue and is used to distinguish neuropathy from muscle disease (myopathy). These tests often are used in combination and are referred to as EMG/NCV studies.
When EMG/NCV studies are inconclusive, nerve, skin, or muscle biopsy may be performed to confirm the neuropathy diagnosis. Biopsy involves removing nerve, skin, and/or muscle tissue for microscopic evaluation and chemical analysis.
Electroencephalography (EEG), spinal tap (lumbar puncture), blood and urine tests, and imaging tests (e.g., CT scan, MRI scan) may be performed to determine the underlying cause of the neuropathy and to rule out other conditions.
EEG measures electrical activity in the brain and is used to evaluate brain function and detect seizure disorders.
Spinal tap, or lumbar puncture, is performed to analyze cerebrospinal fluid (CSF). This test is used to rule out infectious disease (e.g., meningitis), high or low levels of CSF (e.g., hydrocephalus), and to detect abnormal protein levels. In this procedure, a needle is inserted between two lumbar (lower spine) vertebrae and cerebrospinal fluid is collected and analyzed.