Pick's disease, named after its discoverer Arnold Pick, is a progressive form of dementia. Unlike Alzheimer's disease, which involves deterioration of structures at the back of the brain, Pick's disease involves deterioration of structures in the front of the brain. It is a form of frontotemporal dementia. Pick's disease occurs earlier in life than other forms of dementia, usually between the ages of 55 and 65, and it tends to run in families.
Four variations of Pick's disease
Pick's disease presents subtle symptoms at first. For the first one to three years, people who have the condition do well on quick cognitive screening tests, such as the Mini-Mental Status Examination (MMSE). These tests don't pick up deterioration of inhibition and social judgment, however, and the disease may be disabling before it is diagnosed.
What kinds of social judgment are impaired in Pick's disease? There are well-identified links between the specific areas of brain deterioration and changes in behavior:
- Pick's disease patients with loss of gray matter in the anterolateral orbitofrontal cortex may develop hyperphagia, a desire to eat all the time.
- Pick's disease patients with dorsomedial or dorsolateral frontal dysfunction may become apathetic. They simply may stop caring about their families, their jobs, and themselves. They may lose self-awareness and become unable to understand meanings of turns of phrase and gestures. They lose their abilities to appreciate humor.
- Pick's disease patients with gray matter loss in the bilateral posterolateral orbitofrontal cortex and right anterior insula may develop an insatiable sweet tooth.
- Pick's disease patients with orbitofrontal dysfunction do things that are socially inappropriate and become aggressive. They may act aggressively as if they were motivated by an obsessive-compulsive disorder. Or they just can't stop saying and doing things that embarrass themselves and their families.
These four categories of Pick's disease are not always mutually exclusive. It may not be possible to distinguish exactly which areas of the brain are deteriorating. And it is not always possible to distinguish Pick's disease from other forms of frontotemporal dementia. However, there are predictable patterns in Pick's disease that set it apart from other forms of dementia.
Pick's disease affects one side of the brain
Most other forms of dementia affect both sides of the brain. Pick's disease (for the most part) affects just one side of the brain. As a result, people who have Pick's disease are less likely to develop apraxia (an inability to plan muscle movements) and are less likely to have problems with eye-hand coordination.
Pick's causes incontinence relatively early
On the other hand, people who have Pick's disease lose control of their bladder and bowels relatively early in the disease. Bowel and bladder control are conserved longer in most other forms of dementia, such as Alzheimer's.
Parkinson's and Pick's are not mutually exclusive
People who have Parkinson's disease can develop Pick's disease, and vice versa. People who have Pick's disease can become rigid, or have issues with gait. However, severe rigidity or severe problems with walking suggest that the primary condition is Parkinson's, not Pick's disease.
How does the doctor recognize Pick's disease?
Only a doctor who has conducted a medical examination in person can make a diagnosis of Pick's disease or any other form of dementia. However, certain symptoms of the disease are relatively frequent:
- Lack of verbal fluency. Pick's patients may not be able to name the objects in photographs shown them quickly, and not be able to respond to a question quickly. Once they form their response, however, it is grammatically correct and makes sense.
- Inappropriate jocularity (Witzelsucht), telling bad jokes at the wrong time, or telling jokes compulsively or telling jokes all the time. This is distinguished from pseudobulbar affect disorder, which causes laughter or crying when the patient isn't feeling amused or sad. Despite constant joking, the patient does not understand subtle humor. Sometimes the patient only appreciates their own jokes, not someone else's.
- Echolalia, repeating the doctor's words, but not in an attempt to understand them.
- Echopraxia, repeating the doctor's gestures, but not to express the patient's own feeling or emotion.
- Perseveration, repeating the same muscle motion over and over again. A good example of this is doodling.
- Atonia. At rest the patient may have slight tremors, or become rigid. This symptom overlaps with Parkinson's disease.
- Absence of the palmomental reflex, a twitch of the chin when the doctor touches a specific location on the palm. Instead of the normal chin twitch, a Pick's patient may make a suckling motion, a sucking motion, or contort the face into a snout.
Pick's disease isn't diagnosed until the doctor has ruled out hereditary hemochromatosis (which can present some of the same symptoms), brain tumors, brain aneurysms, Creutzfeldt-Jakob disease, meningitis, and several other rare conditions.