Dementia lacking distinctive histology (DLDH)
by André Delacourte
These FTD are also named FTD non-Alzheimer, non-Pick, to emphasize that there are no accumulation of tau proteins. However, levels of normal tau protein are dramatically decreased, suggesting that this fronto-temporal dementia is also a tauopathy (“tau-less tauopathy”: Zhukareva et al, 2001).
Fronto-temporal dementia, non-Alzheimer, non-Pick Frontal lobe degeneration
Symptoms and course
The symptoms are similar to FTD. Typically, during the initial stages of fronto-temporal dementia, memory will still be intact, but the personality and behaviour of the person will change. The person may lose their inhibitions and become extrovert, or alternatively may become apathetic and withdrawn. They may talk to strangers, make inappropriate remarks in public and be rude or impatient. They may become aggressive which may be quite out of character, and may develop fixed routines. Some people begin to hoard things and become obsessive. Behaviour may be sexually suggestive, though a loss of interest in sexual acts themselves is also common. Often the person with dementia will be unaware of the problems.
People may also develop a sweet tooth and overeat leading to gain in weight. Excessive alcohol intake may occur. Spending money and losing cash often causes problems. In the later stages people with the illness may compulsively put objects in their mouths.
In the early stages memory is not usually affected. However sometimes difficulties in organisation and concentration may lead to an apparent memory problem. People may be very distractible.
Later in the disease a more generalised dementia can develop, and symptoms will usually appear to be similar to those with Alzheimer's disease. Those affected may no longer recognise friends and family and may need nursing care, become incontinent and bed-ridden.
Average age of onset : 50 to 60 Duration of the disease : several years
Causes and risk factors
DLDH is likely heterogeneous. Indeed, in addition to the previous description, there are DLDH not linked to tau.
- non tau FTD linked to chromosome 3
- FTD with Motor neuron disease:
- Amyotrophic Lateral Sclerosis (ALS) can be associated with FTD
- Guam ALS is also a rare form of FTD and ALS found in the Chamorro population of Guam island. Tangles (tau pathology) is also well developed in neocortical areas
Not rare among non-familial FTD cases
In order to differentiate FTD from AD, in addition to the clinical assessment, CT and MRI scans may be helpful demonstrating frontal atrophy. Functional imaging (PET, SPECT) in typical cases show frontal / temporal hypometabolism.
Care and treatment
As yet there is no cure for fronto-temporal dementia and the progression of the condition cannot be slowed.
Drugs that are designed for the treatment of Alzheimer's disease, such as Aricept ® and Exelon ® may increase symptoms. Symptomatic for disinhibition and behavioural problems. Antidepressants for apathy. Trazodone for agitation. No prevention.
Ongoing research / clinical trials
Research on the physiopathology of tau proteins, likely involved in the process
- Lebert F, Stekke W, Hasenbroekx Ch, Pasquier F.Fronto-temporal dementia. A randomized, controlled trial with trazodone. Dem Cogn Disord. (in press)
- Tolnay, M. and A. Probst (2001). Frontotemporal lobar degeneration. An update on clinical, pathological and genetic findings. Gerontology 47(1): 1-8.
- Zhukareva V., Vogelsberg-Ragaglia V., Van Deerlin V. M., Bruce J., Shuck T., Grossman M., Clark C. M., Arnold S. E., Masliah E., Galasko D., Trojanowski J. Q. and Lee V. M. (2001) Loss of brain tau defines novel sporadic and familial tauopathies with frontotemporal dementia. Ann Neurol 49, 165-175.
Last Updated: vendredi 09 octobre 2009