Dear Doctor: My wife does calligraphy, but she’s having trouble because her hands have started shaking. She’s worried it’s Parkinson’s disease. What else could be the cause?

Dear Reader: Uncontrolled shaking, trembling or quivering, which is known as a tremor, occurs as the result of sustained and involuntary muscle contractions in the affected area. A tremor can range from something so slight that the person barely notices, to more pronounced movement that interferes with daily activities. Although tremors mostly involve the hands, they can affect virtually any muscle in the body, including those in the head and neck, vocal cords, legs, feet, arms and torso. The movement may occur at irregular intervals with periods of stillness in between episodes, or it can be constant. And while the condition becomes more common as people enter their later years, it can occur at any age.

There are two major types of tremor -- resting and action. In resting tremor, which most often involves the hands and fingers, the affected body part shakes or trembles when the muscles are relaxed and at rest. An action tremor occurs when the muscles are engaged. This can happen during general movement, like when you pat a dog or pass a plate; while bracing a body part, such as holding out an arm; when engaging in a fine motor task, such as writing; or while zeroing in on a specific target, such as touching the tip of one’s nose.

Tremors can occur without a discernible cause; may be a symptom of a physical, medical or neurological condition; or can result from medical treatment. Many of us have experienced the shaky hands that can accompany fear, anxiety, anger, anticipation and exhaustion. Substances like caffeine, alcohol and nicotine can contribute to tremors. So can a range of drugs, both legal and illicit. Medications that may cause tremor include those used to manage asthma, certain antidepressants, some types of blood pressure drugs, thyroid medications, weight-loss medications, anti-inflammatory drugs and antivirals.

It’s true that tremor can be a symptom of a neurological disorder, including Parkinson’s disease. In your wife’s case, it is likely an action tremor because it occurs while she is writing. Parkinsonian tremor falls into the category of the resting tremor: A person with Parkinson’s disease will notice that their fingers or hands tremble while at rest, and that as soon as the muscles are engaged in activity, the tremor disappears. However, since any type of tremor can be a symptom of an underlying condition, it’s a good idea for your wife to speak about it with her family doctor.

Diagnosis entails a comprehensive physical and neurological exam, a detailed medical history, performance tests and certain laboratory tests. Imaging tests such as CT scans or MRI don’t diagnose tremor, but may be used to rule out other conditions. There is no cure for tremor at this time, but with medication and, in some cases, surgery, the condition often can be successfully managed.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our son’s work as an engineer is taking him to Kampala, Uganda. He’s had to get all sorts of vaccinations, but his mother is concerned that Ebola wasn’t on the list. Is there a vaccine yet?

Dear Reader: After decades of research and testing, an injectable vaccine that targets the deadly Ebola virus in humans won approval from the European Union in late November. Known as Ervebo, the vaccine also meets standards of quality, safety and efficacy set forth by the World Health Organization. In the United States, the Food and Drug Administration has placed the vaccine under priority review, but it is not yet available here.

Ebola virus disease, or EVD, is a rare and often fatal illness that affects both humans and nonhuman primates. The family of viruses that cause EVD are found mainly in sub-Saharan Africa, but because the disease is highly contagious, the WHO considers it a potential global threat. The virus is originally transmitted to people from animals, including fruit bats, porcupines and nonhuman primates. It then spreads through direct contact with the blood or bodily fluids of someone who is sick with, or died from, EVD. The average fatality rate of the virus is 50%. There is no evidence of transmission of the Ebola virus by mosquitoes or other insects.

Symptoms can appear from two days to three weeks after infection. The disease typically begins with bodily aches and pains, often including a sore throat or severe headache, accompanied by a fever. Weakness, fatigue, intestinal pain and vomiting are also possible. Some patients experience hemorrhaging, bleeding or bruising, which gave the disease its original name of Ebola hemorrhagic fever.

Health care workers and others tending to patients with EVD, and laboratory workers dealing with the bodily fluids of an infected individual, are at highest risk of contracting the disease. The disease is also easily transferred to family and friends in close contact with someone who is sick, or even with the surfaces and materials the infected person contaminated.

There is no cure for EVD at this time. Since its discovery in 1976, the largest outbreak of EVD occurred from 2014 to 2016; more than 11,000 people died in Guinea, Liberia and Sierra Leone.

The new vaccine, which protects against the Zaire species of Ebola, had been in limited use on a “compassionate basis” during the most recent outbreak of the disease in the Democratic Republic of Congo. It has been reported to be more than 97% effective at preventing infection. Still, more than 3,000 cases have been reported, included several in Uganda.

Thanks to the recent bureaucratic green light, nations most at risk of an outbreak will soon begin to receive the vaccine for distribution. The pharmaceutical company Merck reports that it has donated more than 250,000 doses of the vaccine for use by the WHO. With the vaccine now fast-tracked by the FDA, manufacture of the drug is expected to begin in the fall of 2020.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Can you talk about FTD dementia, especially the type that affects behavior? I am sure that a close acquaintance has it, although she is clear-minded. Her symptoms involve increasingly strange behavior and, lately, social withdrawal.

Dear Reader: You’re referring to a group of brain disorders known as frontotemporal dementia, or FTD. Originally identified about a century ago, the condition is caused by damage to the nerves, also known as neurons, in the frontal and temporal lobes of the brain. For reasons that are not yet understood, people with FTD experience a buildup of certain proteins within these two areas of the brain. This leads to the progressive loss of structure, and even death, of the neurons, which causes these lobes of the brain to shrink.

Unlike Alzheimer’s disease, which typically begins with cognitive problems and memory loss, the onset of FTD is marked by changes to the individual’s personality, social behavior or language abilities. This is due to the specific functions performed by the areas of the brain affected by FTD. The frontal lobe, one of the four lobes of the human brain, is involved in mood, personality, emotional expression, self-awareness, language and judgment. The temporal lobe, which processes sound, also plays a key role in understanding and using language, and in the management of sensory input, including pain, visual stimuli and emotion.

Depending on the specific site of the nerve damage, symptoms of FTD can show up as either problems with language or changes to behavior and personality. The type of FTD that you’re asking about, known as behavioral variant FTD, affects about half of all people with the condition. In this type of FTD, an individual’s personality begins to gradually change. They lose inhibitions, which leads to inappropriate social behavior. They can become impulsive and tactless; lose the ability to feel sympathy or empathy; can’t think logically or solve problems; and are unable to plan ahead. They also lose self-awareness, so they’re unable to recognize the changes that are taking place.

The second major type of FTD features disturbances to the ability to speak, read and understand language. It can also include behavioral changes. Some people diagnosed with FTD also experience changes to reflexes, muscular weakness and a slowing of their movements.

FTD is the most common type of dementia in people under the age of 60. About two-thirds of cases of FTD occur between ages 45 and 65. Diagnosis includes a detailed medical history; tests to assess behavior, memory, language and neurological function; and brain scans to look for atrophy. The cause of this type of dementia is unknown, but researchers have connected it to certain genetic mutations. It’s not inherited, but FTD does run in families. Up to 40% of diagnosed patients have a family history of the condition.

Unfortunately, there is no cure at this time. Although your friend’s behavior does match certain symptoms of FTD, other potential causes can include physical illness, substance abuse and mental illness. If you’re interested in additional information and support relating to FTD, visit theaftd.org.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)