How do brain lesions diagnose multiple sclerosis, lewy body dementia, etc?

Diagnosis/symptoms: Brain lesions are the actual physical changes in the structure of the brain or individual cells of the brain that account for the psychiatric symptoms we may see, for example tangles and plaques in alzheimer's disease that cause clinical symptoms like memory loss or mood/personality changes. Some brain lesions are found on imaging, like a ct or MRI scan, while others requires microscopic exam.

It's what makes: Up the lesions that tell us what we are dealing with.

LBD Clinical only: Neurodegenerative, progressive d/o with  milder physical parkinsonism than parkinson's disease typically. (slowed movements, stiff/rigid muscles & posture, possibly resting tremor). But with early dementia, often with associated psychosis (visual hallucinations/delusional thoughts, excessive sleepiness, depression, anxiety, apathy, & rbd=rem behavior d/o, causing acting-out of dreams in rem sleep.

Use of MRI testing: The brain lesions in MS are seen within white matter in particular patterns, and different lesion ages can confirm MS. Lewy body dementia is more difficult to diagnose looking for specific lesions and PET scan with decreased occipital lobe metabolism can confirm. Likewise, PET can show specific patterns for fronto-temporal and Alzheimer's dementias.