Hypothesis: There exists patients who have met ALS or PMA diagnostic criteria and subsequently experienced robust and sustained improvement, i.e. a "reversal." Thirty-eight of these patients were identified in the prior Duke University study, Documentation of Known ALS Reversals (St.A.R. Protocol 1, Duke IRB Pro00076395). The investigators hypothesize these patients have had different environmental exposures than patients with typically progressive ALS. Identification of specific environmental influences may point to exposures which are protective or exposure that lead to the development of a rare and novel reversible ALS-like disease.

Objective: This study seeks to identify environmental exposures associated with ALS reversals.

Amyotrophic Lateral Sclerosis (ALS) is a devastating motor neuron disease that typically causes rapidly progressive muscle weakness, disability and premature death. In spite of a large number of attempted ALS trials, there are no significant disease-modifying therapies for this condition to-date.

There exists a small group of patients who meet diagnostic criteria for ALS or progressive muscular atrophy (PMA), progress for a period of time, and then significantly improve. Some of these "ALS reversals" even make a complete recovery back to normal neurological function. The investigators have independently verified 38 of these cases so far through review of medical records and peer-reviewed literature. These patients are different in their demographics and disease characteristics as compared to patients with more typically progressive ALS.

One possible explanation for these cases is that these patients have had protective environmental exposures. Another possible explanation is that these patients have had unique environmental exposures that led to a reversible form of ALS. Study of these selected reversal patients may yield valuable clues to environmental mechanisms of ALS resistance.

This is a pilot case-control study attempting to discover environmental exposure correlates to ALS reversals. The investigators will recruit and enroll ALS reversal "cases" to fill out an online survey form about their life. Topics include demographics, employment history, military service, substance use, physical activity, family medical history, disease progression, residential history, occupational exposures, home exposures, hobby exposures, hormonal and reproductive history (female identifying subjects only), caffeine, head and neck injuries, electrical shocks, health insurance, subjective perception of the etiology of ALS, and clinical features of disease. "Control" participant data will come from a pre-existing database.

Inclusion Criteria:

• Prior participation in Documentation of Known ALS Reversals (Duke IRB Pro00076395)
• Confirmation of ALS or PMA (primary muscular atrophy) diagnosis through medical record review (previously documented in Documentation of Known ALS Reversals protocol)
• Sustained, robust improvement on at least one objective ALS outcomes measure (ex. ALSFRS-R, FVC, strength testing, EMG) (previously documented in Documentation of Known ALS Reversals protocol)
• Able to understand English

Exclusion Criteria:

• History of cognitive impairment severe enough to preclude informed consent, reported by patient on direct questioning or as suspected by research personnel from Documentation of Known ALS Reversals (Duke IRB Pro00076395) study data

Participants will be recruited from the cohort of subjects (38 to-date) who participated in the Documentation of Known ALS Reversals (Duke IRB Pro00076395) protocol and were subsequently thought to have an ALS Reversal.