I would at least ask the questions when obtaining history-specifically regarding occupational exposure to heavy metals like mercury, lead or arsenic. There is also a theory about BMAA a toxic aminoacid made by Cyanobacteria that may explain clusters of ALS-like or Parkinsonian syndrome that occurred...

Risk factors of amyotrophic lateral sclerosis: a global meta-summary (published in Frontiers of Neuroscience in April 2023) looked at genetic and non-genetic risk factors for ALS. 230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four ...