Jim Gibbons, shown at his swearing-in as governor on New Year's Day, has a condition known as familial tremors. Photo by The Associated Press.

When Gov. Jim Gibbons signed a proclamation as his first act in office, he did more than designate Wednesday as a day of mourning for President Ford: He also revealed he suffers from a chronic neurological condition, an ailment that affects as many as 10 million Americans.

As a group watched Gibbons be sworn in Monday and then affix his signature to the document at the state Capitol in Carson City, his hand trembled so noticeably at both functions that he felt compelled to explain he has a condition known as familial tremors.

Often misidentified as Parkinson's disease, a more serious neurological condition, familial tremors is a term used to further explain a neurological disorder -- essential tremor -- that tends to run in families.

He told the gathering that his tremors, which he characterized as nothing more than "annoying" and not threatening to his job performance, have gotten worse and were exacerbated recently by a caffeine-laced drink and a subsequent lack of sleep.

Though some people with the condition take medication and can elect to have brain surgery to correct the symptoms, the tremors may be mild and nonprogressive throughout life for others.

Gibbons' communication director, Brent Boynton, said Wednesday that the governor's mother and other members of his family have the condition.

"This is nothing that should affect the governor's performance," Boynton said. "He is not a brain surgeon."

Boynton said Gibbons did not have time Wednesday to talk about his medical condition.

Gibbons, 62, is not on medication for the condition and has no plans for surgery, Boynton said.

The governor's press secretary, Melissa Subbotin, refused to ask Gibbons Wednesday when he was first diagnosed with the condition and also declined to ask him how quickly the disorder is progressing.

Dr. Jaimie Henderson, a Stanford University School of Medicine neurosurgeon, said the disorder can grow to be so debilitating with advancing age that an individual with the condition cannot feed himself.

Stress and caffeine often worsen the condition, which can result in the trembling of hands, head, voice, legs or trunk, Henderson said.

Alcohol helps stop the trembling temporarily, he said.

Essential tremor is a result of abnormal communication between certain areas of the brain, including the cerebellum, thalamus and brain stem, according to Las Vegas neurosurgeon Daniel J. Broeske. The cause of the disorder is unknown.

Broeske said he believes the governor can help educate the public about the condition.

Evidence shows the tremor is genetic, giving each child of a parent with essential tremor a 50 percent chance of inheriting a causation gene. Sometimes, people without a family history develop the disorder.

Though newborns and infants have been diagnosed with the condition, the average age of onset is 45.

Public figures best known with the condition were actress Katharine Hepburn and current U.S. Sen. Robert Byrd, D-WV.

"Neither one of those people would agree to be a spokesman for the condition and help educate the public," said Catherine Rice, executive director of the International Essential Tremor Foundation, based in Kansas. "Perhaps we can convince your new governor to be our spokesman. That way we can get funding to find out the cause of the condition as well as new drugs to treat it."

Experts believe only a small percentage of people with essential tremor seek medical assistance, including drug therapies that are commonly used for high blood pressure or epilepsy.

Another therapy involves injecting Botulinum toxin into muscles, Rice said. That has been successful in the treatment of some patients with head and voice tremors.

Surgical procedures include thalamic stimulation, which involves implanting an electrode deep into the brain.

By sending electrical current through the electrode, communication between tremor cells can be interrupted. Within seconds of activation, tremor reduction occurs and can be dramatic. Significant or complete tremor reduction occurs in approximately 80 percent of people.

But Henderson said the surgery risks can be daunting.

"There is a 1.5 percent risk of a stroke and also a risk of infection with the surgery," he said.

The most notable differences between essential tremor and Parkinson's disease is that Parkinson's patients have a tremor that usually is most prominent at rest.

Essential tremor patients have a tremor that is noticeable when they hold out their hands or hold an object such as a pen or a cup.

Stiffness and slow movement also characterize Parkinson's.

"At this point, I would say the governor's medical condition is a minor irritant," Boynton said. "We'll just make sure he sticks to decaffeinated coffee."