Diagnosing ALS

Being diagnosed with ALS (Lou Gehrig's disease) is not as simple as taking a blood test or getting an X-ray. No test can prove with certainty that someone has ALS.

Before an ALS diagnosis can be made, a health care provider must observe certain symptoms and signs. After giving a full medical history, a patient may receive neurologic examinations at regular intervals to see whether symptoms are getting worse. Symptoms may include:

• Muscle weakness
• Muscle atrophy – the wasting away of muscle mass after long periods of disuse
• Hyperreflexia – overactive reflexes, including twitching and spastic movement
• Spasticity – the tightening and contraction of muscles, muscle stiffening

Ruling out other diseases

In some cases, infectious diseases and neurological disorders can cause ALS-like symptoms. Tests are run to rule out other possible diseases that have similar symptoms. Patients may be given tests such as:

Electromyography (EMG) – An EMG test detects electrical activity in muscles; certain findings can support the diagnosis of ALS.

Nerve conduction velocity (NCV) test - Abnormal results in the NCV may suggest that a patient has damage to peripheral nerves or muscle disease rather than ALS.

Magnetic resonance imaging (MRI) – Using a magnetic field and radio waves, a detailed image of the brain and spinal cord can be seen. The MRI images won't reveal ALS, but can reveal evidence of other problems that may be causing the symptoms.

Based on the patient's symptoms and findings from the examination and tests, a health care provider may order routine laboratory tests. Patients may also have blood and urine samples tested to eliminate the possibility of other diseases.

After being diagnosed with ALS, patients may wish to obtain a second neurological opinion (or referral to a specialized center) to rule out disorders that can resemble early stages of the disease.