maybe an environmental toxin? Carbon monoxide leak from a stove, water heater, A/C- heater unit? CO can also leak into the car if the system is faulty. It tends to have an affinity for the cerebellum, hippocampus. I replaces oxygen in the blood and therefore the brain (possible causing atrophy) With long term exposure, symptoms don't necc. clear up once you leave the house. Have a HVAC specialist check out for CO leaks. Or a natural gas leak?