Biomarkers in Neurodegenerative Diseases

Inclusion Criteria: 1. Diagnosis of MCI, AD, DLB, FTLD, PDD, TEA, TLE, SCA, HAND, ALS, PLS, or normal control. 2. Age 18 or older 3. Reliable informant with frequent contact with participant 4. Mini Mental State Exam (MMSE) ≥15 AND/OR Clinical Dementia Rating (CDR) less than 2 5. Able to undergo extensive psychometric testing Exclusion Criteria: 1. Any conditions that could account for cognitive deficits in addition to a neurodegenerative disease, including but not limited to: * Past or present diagnosis of Korsakoff's syndrome * Alcohol or substance abuse preceding dementia \& still present within 5 years of onset * Present untreated vitamin B12 or folate deficiency * Present untreated hypothyroidism * Past or present head trauma with persistent deficits * Present untreated syphilis * Past or present multiple sclerosis or another neuro-inflammatory disorder * Past or present vascular or multi-infarct dementia * Past or present diagnosis of huntington's disease * Past or present normal pressure hydrocephalus * Past or present central nervous system (CNS) lesions deemed to be clinically significant * Unresolved or present subdural hematoma * Past or present Ischemic Vascular Dementia * Past or present intracerebral hemorrhage * Present systematic liver disease * Present renal insufficiency requiring dialysis * Present encephalitis or meningitis * Present anxiety disorder (not due to dementia and requiring medication more than 3x per week) * Present severe periventricular white matter disease or greater than grade 4 white matter lesions * Present lacunar infarcts deemed to clinically significant * Present cortical stroke * Present respiratory condition requiring oxygen 2. Present significant systemic medical illness, such as cancer requiring chemotherapy or end stage cardiac insufficiency 3. Present inability to safely scan in an MRI 4. Present pregnancy or lactation - Female participants will be asked to confirm that they are not pregnant and do not plan to become pregnant. 5. Present current medication likely to affect CNS functions: * Benzodiazepines (no triazolam, but other short-acting benzodiazepines are OK) * Antidepressant therapy with amitriptyline or doxepin or tx not stable during past year * Neuroleptics in the phenothiazine and haloperidol families (atypicals OK) * Narcotics (codeine is OK, but hold 24 hours before neuropsychological testing) * Anti-seizure medication outside of therapeutic ranges * Antihistamines (\> 3x per week; hold 24 hours before neuropsychological testing)