NIAAA data show long exposure to high proof alcohol leads to structural changes in areas like the prefrontal cortex and hippocampus. These changes include loss of gray matter volume, not only a shift in mood or behaviour. MRI studies show heavy drinkers of strong alcohol face 10% to 15% reduction in frontal lobe size over ten years. Higher ethanol concentration increases damage speed because BAC rises faster than the liver can process at a rate of 0.015% per hour. Regions studying proof alcohol Alabama show a link between high volume spirit use and an increase in neurological hospital cases.