Most often, abnormal results are due to nerve damage or destruction, including:
- Axonopathy (damage to the long portion of the nerve cell)
- Conduction block In this the impulse is blocked somewhere along the nerve pathway
- Demyelination (damage and loss of the fatty insulation surrounding the nerve cell)
The nerve damage or destruction may be due to many different conditions, including:
- Alcoholic neuropathy
- Diabetic neuropathy
- Nerve effects of uremia (from kidney failure)
- Traumatic injury to a nerve
- Guillain-Barré syndrome
- Diphtheria
- Carpal tunnel syndrome
- Brachial plexopathy
- Charcot-Marie-Tooth disease (hereditary)
- Chronic inflammatory polyneuropathy
- Common peroneal nerve dysfunction
- Distal median nerve dysfunction
- Femoral nerve dysfunction
- Friedreich ataxia
- General paresis
- Mononeuritis multiplex (multiple mononeuropathies)
- Primary amyloidosis
- Radial nerve dysfunction
- Sciatic nerve dysfunction
- Secondary systemic amyloidosis
- Sensorimotor polyneuropathy
- Tibial nerve dysfunction
- Ulnar nerve dysfunction
Any peripheral neuropathy can cause abnormal results. Damage to the spinal cord and disk herniation (herniated nucleus pulposus) with nerve root compression can also cause abnormal results.