What is frontotemporal dementia, or Pick's disease?

Answer: Frontotemporal dementia (FTD) is a rare, neurodegenerative disorder that results in severe deficits in cognition.

Frontotemporal dementia, formerly called Pick's disease, is a progressive neurodegenerative disease that is generally diagnosed when a patient is in their 40s-60s. It is the second-most common cause of early onset dementia, after Alzheimer's disease. 

Symptoms

One of the earliest and most profound changes observed in a person with frontotemporal dementia is a change of personality. This is a meaningful symptom that allows for differential diagnosis between Alzheimer's dementia and Pick’s disease: Patients with Alzheimer’s disease show memory deficits before personality changes. 

Relatedly, many people with FTD also experience changes in behaviors. For instance, they may exhibit poor judgment, lack of inhibition, unusual perseverative compulsive behaviors, or a decline in personal hygiene. Many may display inappropriate social behaviors such as a lack of empathy.

Some people with frontotemporal dementia experience a difficulty with using language. They have difficulty finding the correct word to use, replacing specific nouns with generic descriptors. They have a hard time constructing meaningful sentences, and their speech pattern often appears stilted and telegraphic. 

Some forms of frontotemporal dementia manifest in the form of motor disorders. Rarely, they have a tremor or rigidity, poor coordination, and muscle weakness.

Cellular correlates of FTD

One of the trademark pathologies observed in frontotemporal dementia is an accumulation of unusual microscopic protein clumps called Pick bodies. Pick bodies are aggregations of the protein tau, which are proteins that serve a normal physiological function in the healthy brain. Specifically, tau is used by the microtubules of neurons, which are structural proteins that help maintain the three-dimensional shape of axons. 

These accumulations of proteins likely contribute to the atrophy that is observed in cortical gyri. In FTD, Pick bodies are usually found in specific brain regions such as the dentate gyrus and the CA1 of the hippocampus, as well as layers II and IV of the cortex. 

These Pick bodies are generally located in the frontal lobe. As observed in autopsy, degeneration is mainly seen specifically in the frontal lobe while the surface of the parietal, temporal, and occipital lobes are generally unaffected.

Risk factors

The best known risk factor for frontotemporal dementia is a family history of the disease. 

One of the main difficulties is accurate diagnosis of FTD. Many cases get mistakenly diagnosed as Alzheimer's disease, depression, or even schizophrenia.