| Amyotrophic lateral sclerosis (ALS) is difficult to | | | | small shock is passed through the nerve to measure |
| diagnose early because it may appear similar to other | | | | the size and speed of nerve signals. |
| neurological diseases. No test can provide a definite | | | | - Imaging. A doctor may suggest magnetic resonance |
| diagnosis of ALS, although the presence of upper and | | | | imaging (MRI) or a computerized tomography (CT) |
| lower motor neuron signs in a single limb is strongly | | | | scan to produce brain and spinal cord images. These |
| suggestive. Instead, the diagnosis of ALS is primarily | | | | tests can help the doctor determine if something |
| based on the symptoms and signs the physician | | | | other than ALS may be causing the signs and |
| observes in the patient and a series of tests to rule | | | | symptoms. |
| out other diseases. Physicians obtain the patient's full | | | | - Spinal tap (lumbar puncture). This test analyzes the |
| medical history and usually conduct a neurologic | | | | cerebrospinal fluid surrounding the brain and spinal |
| examination at regular intervals to assess whether | | | | cord. A needle is inserted into the spinal canal to |
| symptoms such as muscle weakness, atrophy of | | | | collect fluid. Tests on this fluid indicate the number |
| muscles, hyperreflexia, and spasticity are getting | | | | and types of white blood cells, the level of sugar, and |
| progressively worse. | | | | the levels and types of proteins. Additional tests on |
| Diagnostic tests for ALS may include: | | | | this fluid can indicate evidence of bleeding, infection |
| - Electromyogra (EMG). Electromyography measures | | | | and abnormal cells. |
| the tiny electrical discharges produced in muscles. A | | | | - Blood and urine tests. Analyzing samples of blood |
| thin-needle electrode is inserted into the muscles the | | | | and urine in the laboratory may help the doctor |
| doctor wants to study. An instrument records the | | | | eliminate other possible causes of signs and |
| electrical activity in the muscle as it rests and | | | | symptoms. |
| contracts. | | | | - Muscle biopsy. If the doctor detects muscle disease |
| - Nerve conduction study (NCS). As part of an | | | | rather than ALS, the doctor may recommend a |
| electromyography study, two electrodes are taped | | | | muscle biopsy. In this procedure, a small portion of |
| to skin above a nerve or muscle to be studied. A | | | | tissue is removed and sent to a lab for analysis. |