Understanding Semantic Dementia & Living with It

Semantic dementia (also called Pick’ s Disease) is a variant of frontotemporal dementia (FTD). While Alzheimer s disease is the most common and well-known form of dementia, FTD is another variant. It’s a term used to describe several disorders that affect the brain’ s frontal, left, and right temporal lobes.

Frontotemporal dementia may be hard to live with and a little harder to understand, especially for a family member taking care of a senior. This article hopes to help you understand what semantic dementia is to help your loved one deal with the everyday challenges. 

What is Semantic Dementia?

What is semantic dementia | My Delta Care

According to an article by Maria Luisa Gorno-Tempini (Behavioral Features in Semantic Dementia vs. Other Forms of Progressive Aphasias), semantic dementia is distinguishable from other FTD, specifically with behavioural characteristics typical of frontotemporal dementia.

Semantic dementia (SD) is the progressive fluent aphasia of variant frontotemporal dementia and is primarily associated with temporal lobe involvement.

How does semantic dementia manifest: 

However, patients with this disorder retain the ability to speak fluently and have a relatively preserved episodic memory. This syndrome’s cognitive loss seems to be in the permanent store of long-term memory representing general conceptual knowledge-semantic memory.

SD patients don’t perform well on tests of semantic knowledge. Nobody knows why semantic memory is impaired, and semantic information deteriorates in SD patients. This theory is supported by the deterioration of the anterior temporal lobe, which is believed to contain a semantic system component that integrates conceptual information.

What part of the brain is usually damaged in semantic dementia?

What part of the brain is usually damaged in semantic dementia | My Delta Care

In Semantic Variant Primary Progressive Aphasia, there is a build-up of a protein called TDP-43 in the left side of the brain tissue, which controls speech and language (giving SD patients language disorders) called left temporal lobe atrophy. 

This protein usually occurs, but nobody understands what causes it to build up in large amounts in this brain area.

As more and more TDP-43 forms, the brain cells are unable to function and eventually perish. SD causes the brain’s temporal lobe to shrink, seen in a positron emission tomography (PET) scan or magnetic resonance imaging (MRI). (Using simultaneous PET/MRI to compare the accuracy of diagnosing frontotemporal dementia by arterial spin labeling MRI and FDG-PET, University of Western Ontario) 

How long can you live with semantic dementia?

Research suggests that people with Semantic Variant Primary Progressive Aphasia may live an average of 12 years, although this can vary per patient. 

What is the life expectancy of someone with frontotemporal dementia?

What is the life expectancy of someone with frontotemporal dementia semantic dementia | My Delta Care

The rate at which FTD progresses differs significantly, with life expectancy ranging from less than two years to 10+ years. On average, people live for about 6 – 8 years after the start of symptoms

Patients with probable progressive nonfluent aphasia, a variant of FTD, typically live about 3-12 years after being diagnosed initially. 

Is semantic dementia hereditary?

Unlike other forms of frontotemporal dementia, most cases of semantic dementia occur ‘out of the blue,’ and no other family members are affected. In a small number of cases, the family’s condition runs and is passed through the genes. 

Who is at risk of semantic dementia?

Who is at risk of semantic dementia | My Delta Care

The cause of frontotemporal lobar degeneration is not known. Most patients with SD start to have symptoms in their 50s or 60s, although some have shown signs earlier or later. 

The probability of developing it increases considerably with age. However, SD can affect younger people too. 

Living with semantic dementia

People living with dementia may be prone to tantrums, disconcerting habits, and many more changes. These are normal and should be expected. Below are more things to expect when caring for someone who lives with semantic dementia. 

Living with routines

The patient may be unable to adjust their actions in new situations and they misbehave. They might 'sulk' or throw a tantrum because they are stopped from doing something in their routine.

Their words and topics in conversation may also be routine and repeat the same. (Hoarding and Obsessive-compulsive Behaviours in Frontotemporal Dementia: Clinical and Neuroanatomic Associations, Lancet Neurol)

Policing and protecting

Policing and protecting, essentially monitoring your loved one with semantic dementia, will be hard. Patients won't be able to do a lot of the stuff they once could, and while they still will try, it's dangerous to leave them to it. Their semantic dementia impairs their understanding of how some things work, making them susceptible to mistakes.

Making connections

Connecting with your loved one with semantic dementia may become much harder now (Distinct Behavioural Profiles in Frontotemporal Dementia and Semantic Dementia, J Neurol Neurosurg Psychiatry, UK).

With their struggles with word meaning, it's best to accommodate single-word comprehension. Also, it will feel like you can't make a deep, emotional connection anymore. The person's response may also have more movements and fewer words than you're used to, but that's normal.

Being adaptive and flexible

You need to be adaptive and flexible because your loved one with semantic dementia may have a change in interests. Someone with semantic dementia may once liked sports but now can't stop mentioning ballet dances and performances. Be adaptive to these changes, and expect them to have drastic personality changes and not resemble themselves from before.


Dealing with patients with semantic dementia and Alzheimer s disease is challenging. It can be frustrating, especially if the person with semantic dementia is almost nothing like who they were before. There is a cohort study, The Selective Impairment of Semantic Memory from the Quarterly Journal of Experimental Psychology (Q J Exp Psychol), you can take a look. Or, a professional article online, The Core and Halo of Primary Progressive Aphasia and Semantic Dementia from Department of Neurology, Annals of Neurology (Ann Neurol).

As someone caring for an aged with dementia, be sure to take a break and ask for help, information, and navigation, whether from other family members or doctors. As the disease progresses, especially in the later stages, knowledge can become increasingly needed, so there’s no shame in seeking it.

Scroll to Top
Delta Care