Frontotemporal dementia, or FTD, is a neurodegenerative disease that affects adults, with an average age of onset between 50 and 60. It is the second most common early onset dementia after Alzheimer’s disease, occurring in about 1 per 10,000 people over the age of 50. It is equally common in men and women.
It gets its name because it affects the frontal and temporal lobes of the brain. It is therefore sometimes also called frontotemporal lobar degeneration or FTLD. The disorder used to be called Pick’s disease, and this name is occasionally still used.
In about a third of people with FTD the disease is caused by an abnormal gene that has been passed on from one generation to another, a pattern of inheritance known as autosomal dominant. It remains unclear exactly why the other two thirds of people with FTD develop the condition.
FTD is actually a group of disorders that overlap with each other. Usually the first symptoms are either changes in people’s behaviour, which we call behavioural variant FTD, or impairment in their language skills, which we call primary progressive aphasia,or PPA. PPA can be further split into two subtypes, known as semantic dementia, or SD, and progressive nonfluent aphasia, or PNFA.
Some people with FTD may also develop disorders that affect movement of the body. Motor neurone disease or MND, is a disease that affects the motor nerves, causing weakness of the muscles that control the limbs, speech and swallowing. It is also called amyotrophic lateral sclerosis, or ALS. Parkinsonian disorders are a group of conditions similar to Parkinson’s disease in that they cause stiffness and slowing of movement rather than weakness. These are also sometimes called parkinsonism. Two particular parkinsonian disorders overlap with FTD, called corticobasal syndrome, or CBS, and progressive supranuclear palsy, or PSP.