An older adult's hands.

"I thought I had Parkinson’s disease!” the 65-year-old stock analyst exclaimed.

Over the past six months, her handwriting had deteriorated to the point that she was having difficulty signing checks. Because a good friend of hers had recently received a Parkinson’s disease diagnosis, she feared the worst.

I began to suspect that her concern was groundless when I noticed that both her hands shook and that she had a barely noticeable to-and-fro motion of her head—two signs that are uncommon in Parkinson’s disease.

And as she walked toward the examining room, her gait was normal and her arms swung freely—hardly the stiff, hesitant shuffle so often seen with Parkinson’s.

The exam turned up none of the other cardinal manifestations of Parkinson’s—the typical masklike facial expression; the slowed, monotonous speech pattern; and the ratchetlike sensation the examiner feels when alternately flexing and extending the patient’s arm.

Moreover, her hand tremors seemed to improve at rest and worsen when asked to do the “finger to nose” test.

The diagnosis was unmistakable: She had essential tremor, a nervous-system problem that causes unintentional shaking, most often starting in the hands. 

Tracking the Cause

The cause of essential tremor remains uncertain, yet it may affect as much as 1 percent of the population worldwide. It usually begins in late middle age and ­often worsens despite attempts to suppress the symptoms.

The limbs, head, and even the voice can shake severely enough to interfere with eating, dressing, speaking, and using the bathroom.

Essential tremor is often called benign in the sense that it is not a life-threatening disease. But many who have it consider it anything but benign.

More on Senior Health

The social stigma can lead to depression and force some into early retirement. The late Katharine Hepburn was a courageous exception; the actress continued to perform and have an active public life despite advanced and fairly severe head tremor.

Recent studies have shown a possible genetic cause. Our stock analyst managed to recall that her grandfather’s hands “shook a bit.” 

There are no laboratory or easily available tests for essential tremor, so diagnosis has to be made entirely on clinical grounds and by selective testing to rule out other diseases, mostly all too obvious, that cause tremors.

These include any long-lasting severe disease that results in muscle weakness or wasting, such as cancer. Thyroid overactivity produces a fine hand tremor (in contrast to the coarse movements seen in essential tremor), and blood tests easily confirm the diagnosis.

Some drugs, including bupropion (Wellbutrin and generic), caffeine, lithium, methylphenidate (Ritalin and ­generic), and pseudoephedrine, can cause tremors.

Various toxins, including lead and mercury, can also cause them. But by and large, essential tremor’s most look-alike contender is Parkinson’s disease, a progressive movement disorder caused by a neuro­transmitter deficit in a specific part of the brain. 

Treating Tremors

For those with mild essential tremor, treatment is available and can be helpful. A small amount of alcohol can diminish symptoms for an hour or two in the majority of people with the condition. ­Although that is not the ideal way to control the disorder on a long-term basis, it can come in handy at times.

The mainstays of medical treatment are propranolol (Inderal and generic), a beta-blocker also used to treat hypertension, chest pain, and migraine headaches; and primidone (Mysoline and generic), an epilepsy drug also helpful in movement disorders.

In addition, various tranquilizers and anti-anxiety drugs have been used because the tremor tends to worsen in tension-producing situations.

Surgical techniques, such as deep brain stimulation and heat ablation, are also now being employed in some very severe cases.

The stock analyst’s relief in learning she did not have Parkinson’s disease was almost enough to improve her tremors. She declined my offer to medicate her.

However, she has taken to having a glass of wine when out for dinner. The only continuing annoyance is getting the glass to her lips for that first sip—after which she’s fine.

Editor’s Note: This article also appeared in the August 2018 issue of Consumer Reports On Health