Approach to motor neuron disease

Motor neuron diseases (MND) consist of a clinical spectrum and are manifested by progressive weakness resulting from the degeneration of motor neurons of the brain, brainstem, and spinal cord. MND is a clinical diagnosis by exclusion of other neurological disorders and supported by findings on electrodiagnostic testing, in the absence of other abnormalities on neuroimaging or serological testing. The spectrum of motor neuron diseases includes a pure lower motor neuron; mixed upper and lower motor neuron; and a pure upper motor neuron variant in addition to regional variants restricted to the arms, legs or bulbar region. Amyotrophic lateral sclerosis (ALS) is a progressive painless mixed upper and lower motor neuron disorder, most commonly sporadic (~85%), which is invariably fatal. Diagnostic approach to MNDs consists of clinical studies, including electrodiagnostic testing, neuroimaging, and laboratory tests, are routinely obtained to find support for the diagnosis and exclude treatable disorders and ALS mimics. upper motor neuron findings can only be determined clinically, although emerging testing may aid in this assessment. Electrodiagnostic testing assesses for the presence of lower motor neuron dysfunction and excludes other neuromuscular disorders include peripheral nerve diseases, such as multifocal motor neuropathy with conduction block.