This study will use a magnetic resonance imaging technique called nuclear magnetic spectroscopy (H-MRS) to define the pathology and progression of primary lateral sclerosis, hereditary spastic paraplegia and amyotrophic lateral sclerosis and assess the usefulness of this technique in evaluating patients' response to therapy. H-MRS will be used to examine metabolic changes in the parts of the brain and spinal cord (motor cortex and corticospinal tract) involved in movement.

Normal volunteers and patients with primary lateral sclerosis, hereditary spastic paraplegia or amyotrophic lateral sclerosis between 21 and 65 years of age may be eligible for this study. Participants will have up to five H-MRS studies, including baseline and follow-up tests. For this procedure, the subject lies on a stretcher that is moved into a strong magnetic field. Earplugs are worn to muffle the loud knocking noise that occurs during switching of radio frequencies. The subject will be asked to lie still during each scan, for 1 to 8 minutes at a time. Total scanning time varies from 20 minutes to 2 hours, with most examinations lasting between 45 and 90 minutes. Communication with the medical staff is possible at all times during the scan.

Standard MRI imaging of the brain shows no consistent abnormalities in many degenerative disorders with progressive upper motor neuron symptoms, including primary lateral sclerosis, hereditary spastic paraparesis, and amyotrophic lateral sclerosis. Nuclear magnetic resonance spectroscopy (H-MRS) is able to evaluate certain cerebral metabolites that reflect the functioning and integrity of neurons. The objective of this protocol is to study metabolic changes in the motor cortex and corticospinal tract using MRS in these disorders to characterize the pathology, the progression of the diseases, and assess the utility of MRS to follow the response to therapies.

INCLUSION CRITERIA:

Adult patients with PLS, HSP, and ALS already evaluated by protocol #01-N-0148.

Adult normal volunteers

EXCLUSION CRITERIA:

Pregnancy, implanted devices such as pacemakers, medication pumps or defibrillators, metal in the cranium except the mouth, intracardiac lines, history of eye shrapnel injury or any other condition/device that may contraindicate or prevent the acquisition of an MRI.