This is diagnosed by MRI of the brain, and since your MRI only showed a few nonspecific foci, this means there is no tumor.
Multiple sclerosis can cause
vertigo, but often, other
symptoms are present as well. A normal MRI of the brain excludes multiple sclerosis; the description you provide of your MRI does not suggest MS. Thyroid problems can also lead to vertigo. Your symptoms really are not consistent with Alzheimer's disease, parkinson's disease, or ALS, so you can rest these fears.