Karen Weintraub

Special for USA TODAY

A medical condition might explain former President George H.W. Bush’s recent behavior, according to several doctors who are familiar with the condition but not with the President’s case or care.

Bush, 93, who has used a wheelchair for the last five years, was accused recently of groping several women while posing for photographs with them. His office today released a statement saying that the touching and a joke that he has told repeatedly was not meant to be inappropriate. The statement offered an apology to anyone who was offended.

Bush has been diagnosed with a rare condition known as vascular Parkinsonism, which is generally believed to be caused by small strokes that damage the same brain structures as are affected in Parkinson’s Disease.

It’s possible that the strokes or other damage to his brain might explain why he acted inappropriately – and seemingly out of character.

President George H.W. Bush apologizes for sometimes patting women on the rear

Any damage to the frontal lobes, the part of the brain right behind the forehead, can cause personality changes, executive function problems and a loss of self-control, said Dr. Alberto J. Espay, a professor of neurology at the University of Cincinnati.

It “could lead to behaviors that are not voluntary – not entirely under their control or volition,” he said.

While most people with vascular Parkinsonism become introverted and withdrawn, there are “outliers,” said Dr. Jeff Bronstein, a neurologist and director of the Movement Disorders Program at UCLA. Such outliers “become disinhibited and do things they wouldn’t do. That’s very possible.”

Vascular Parkinsonism can also cause depression, behavioral problems and memory problems, Bronstein said. It can lead to executive function problems where the person forgets the steps involved even in simple tasks like walking, Espay added.

Bush’s perpetual, strained smile – which Espay described as “abnormal grimacing” – may be a side effect of the drug levodopa, used to treat Parkinson’s Disease. Levodopa can also cause involuntary movements, Bronstein said.

Levodopa and other medications that are effective in Parkinson’s Disease are “of minimal benefit” against vascular Parkinsonism, Bronstein said, but added that he tries most of his vascular Parkinsonism patients on the drug, and some report feeling a little better.

Ole Isaacson, a professor of neurology at Harvard Medical School, said medications given to patients with vascular Parkinsonism can cause hypersexuality and related behaviors.

Espay has an unconventional view of the cause of vascular Parkinsonism. He doesn’t believe the data supports the idea that blood vessel damage or the accumulation of strokes lead to the condition.

The standard treatments for stroke, including lowering cholesterol and treating diabetes have had no effects whatsoever on vascular Parkinsonism, he said, suggesting that the symptoms would occur regardless of a person’s lifestyle, and likely have a genetic cause.

Plus, while patients with stroke tend to get better over time, vascular Parkinsonism symptoms progress without improvement, he said.

Instead, he thinks vascular Parkinsonism is likely to be caused by abnormalities in the myelin sheath, the white coating on brain cells that gives “white matter” its name. In younger people, multiple sclerosis can also affect this sheathing, which slows and disrupts brain signals.