This invention describes the use of indane acetic acid derivatives which are dual PPAR delta/gamma agonists, and which penetrate the Blood Brain Barrier and achieve effective brain to plasma drug levels at non-toxic doses, for the treatment of neurodegenerative diseases including one or more of the following: Alzheimer's Disease (AD); Huntington's Disease (HD); Parkinson's Disease (PD); Amyotrophic Lateral Sclerosis (ALS); Frontal Temporal Dementia (FTD); Corticobasal Degeneration (CBD); Progressive Supranuclear Palsey (PSP); Dementia with Lewy Bodies (DLB); or Multiple Sclerosis (MS).