FTLD includes dementias such as behavioral-variant FTLD, primary progressive aphasia, Pick’s disease, corticobasal degeneration and progressive supranuclear palsy.
Typical early symptoms include marked changes in personality and behavior and/or difficulty with producing or comprehending language. Unlike Alzheimer’s, memory is typically spared in the early stages of disease.
Nerve cells in the front (frontal lobe) and side regions (temporal lobes) of the brain are especially affected, and these regions become markedly atrophied (shrunken). In addition, the upper layers of the cortex typically become soft and spongy and have abnormal protein inclusions (usually tau protein or the transactive response DNA-binding protein, TDP-43).
The symptoms of FTLD may occur in those age 65 years and older, similar to Alzheimer’s, but most people with FTLD develop symptoms at a younger age. About 60 percent of people with FTLD are ages 45 to 60. Brain research scientists think that FTLD is the most common cause of dementia in people younger than 60. In a systematic review, FTLD accounted for about 3% of dementia cases in studies that included people 65 and older and about 10% of dementia cases in studies restricted to those younger than 65.
Frontotemporal disorders can be grouped into three types, defined by the earliest symptoms physicians identify when they examine patients.