Behavioral Variant Frontotemporal Dementia (Bvftd): Characteristics And Diagnosis Of The Behavioral Variant Of Ftd

Overview of Frontotemporal Dementia (FTD)

‘Dementia’ is a term that most of us are familiar with and, of its characteristics, the most commonly recalled issues are memory problems. The NHS more precisely describes dementia as ‘problems with mental abilities caused by gradual changes and damage in the brain’. There are, therefore, multiple variants of dementia and various issues caused by dementia depending on which parts of the brain are affected. For instance, frontotemporal dementia describes a class of neurodegenerative diseases which primarily affect the frontal and temporal lobes of the brain. Frontotemporal dementia is further classified into two separate clinical types: a behavioral variant (bvFTD) and a language type.¹ We will be discussing the behavioural variant of frontotemporal dementia at length in this article, which is also known as Pick’s disease.

Frontotemporal dementia causes parts of the frontal and temporal lobes to atrophy (shrink).¹ The specific symptoms you observe depend on which structures within these lobes are affected, and to what extent. This is why not everyone with the same diagnosis presents in the same way. The behavioural variant of frontotemporal dementia specifically presents with alterations of the behaviour.

Characteristics of Behavioral Variant Frontotemporal Dementia (BvFTD)

Frontotemporal dementia tends to start at a younger age than other, more common, forms of dementia; most cases of frontotemporal dementia are diagnosed in people aged 45-65, although it can also affect younger or older people, whereas typically dementia affects people over the age of 65. (NHS)

People with bvFTD do not usually recognise the changes in their own behavior, however if you know someone affected by BvFTD you may observe the following signs:²

• Apathy: a lack of interest in previously meaningful activities, this can be observed through the neglect of hobbies, social activities or personal hygiene
• Disinhibition: this is where you become less socially conscious about controlling your impulses or regulating your actions. Signs of disinhibition include uncharacteristic risk taking, making offensive comments, financially irresponsibility and ignoring the personal space of others
• Repetitive or stereotypic behaviour: these are behaviours which are continuously repeated, such as repeating words or phrases, rereading the same book countless times, or hoarding items
• Blunted affect: this appears as a monotonous demeanor, people with blunted affect struggle to show emotions properly and engage in appropriate emotional reactions
• Changes in appetite: prominent changes in appetite such as binge eating, only eating specific food groups, or attempting to eat non-food items
• Memory problems (to much a lesser extent than in other forms of dementia)

Neuropathology of BvFTD

Frontotemporal dementia is caused when clumps of abnormal proteins form inside brain cells. In a lot of cases, the protein associated with dementia is the tau protein, although other protein types are sometimes linked to dementia too. The accumulation of proteins can damage the brain cells and stop them working properly. The exact dysfunction someone experiences will depend on the location of the impaired brain cells: in the case of bvFTD, proteins accumulate and impair the function of brain cells in the frontal and temporal lobes of the brain. These areas are collectively important for controlling language, behaviour, and the ability to plan and organise activities. When abnormal proteins build up in these brain regions, these processes become disturbed.

It's not yet fully understood why abnormal proteins such as tau build up in brain cells, but there's often a genetic component, meaning that people who get frontotemporal dementia are more likely to have relatives who were also affected by the condition. (NHS)

Some people who know they have a family history of frontotemporal dementia find it helpful to talk to their doctor about it;  it should be helpful to talk to your doctor about obtaining a referral to a geneticist who can arrange a genetic test to see if you're at risk. For more information on this, visit the NHS site.

Diagnosis of Behavioral Variant Frontotemporal Dementia

bvFTD is among one of the harder conditions to diagnose due to symptoms overlapping with other conditions. As a result, diagnoses are often considered either ‘possible’ or ‘probable’ with your healthcare provider checking off different criteria for each. 

• Diagnosis of ‘possible’ bvFTD

For you to receive a diagnosis of ‘possible’ bvFTD, you must fulfill three of six features: disinhibition, apathy, loss of sympathy/empathy, compulsive/perseverative behaviors, hyperorality or dietary changes and executive function deficits

• Diagnosis of ‘probable’ bvFTD

For you to meet the criteria for ‘probable’ bvFTD, you must also show signs of functional disability with characteristic neuroimaging findings, in addition to the features noted for a diagnosis of‘’possible’ bvFTD.

Neuroimaging is a useful tool in the diagnosis of bvFTD; the characteristic atrophy of the frontal and temporal lobes in bvFTD can be seen on an MRI scan of the brain. An important consideration is that functional impairment often occurs in bvFTD prior to clear atrophic changes can be seen on MRI. Therefore, the absence of neurodegenerative signs on MRI does not rule out bvFTD.³

Your cognitive abilities may also be assessed, to help your healthcare provider diagnose you. These tests help to measure your cognitive abilities, and to observe how you perform compared to the average, healthy person in your age group. For example the ability to recognise emotions, such as anger and disgust, can be tested.⁴ Additionally, those with bvFTD may have difficulties with concluding what another person is thinking or feeling based off social cues or facial expressions.⁵ Testing these kinds of social-cognitive abilities is particularly helpful in differentiating bvFTD from other forms of dementia.

Ultimately, your diagnosis is likely to be achieved through your healthcare provider’s clinical judgment and by eliminating the possibility of other conditions that are known to cause the symptoms you are experiencing. Your healthcare provider may also take into consideration any family history of bvFTD due to the documented genetic influence - bvFTD is considered to be the most heritable form of frontotemporal dementia.⁶

Challenges in Diagnosis

During the diagnostic process, your healthcare provider will aim to rule out the possibility of other conditions being responsible for your symptoms. This is because the symptoms of behavioural variant frontotemporal dementia can also be indicative of disorders such as obsessive-compulsive disorder, bipolar disorder, depression or schizophrenia. In fact, in one study approximately 50% of the cohort were initially diagnosed with a psychiatric illness before their bvFTD diagnosis was achieved.⁷

The diagnostic process may also require your healthcare provider to reach out and talk with family members or friends of the affected person. This can be helpful in gathering more information because the person directly affected might not have sufficient insight into their own condition or symptoms. This feature of the diagnosis relies heavily on the family and friends spending enough time with the person to have a valid insight into their experience.

There is no single test that can definitively diagnose bvFTD, which can make the diagnostic process feel long, complicated and frustrating. You’re likely to be asked to do several tests, and to answer many questions. These are all very important sources of information for your healthcare provider, because achieving an accurate diagnosis will enable you to access the most suitable treatment. 

Treatment of bvFTD

There is currently no treatment option which alters the course of bvFTD, and treatment options must be tailored to the specific individual and the symptoms which are most pronounced in their case. Some people with bvFTD may be prescribed the following medications:

• Selective Serotonin Reuptake Inhibitors (SSRIs) may help with disinhibition, impulsivity, repetitive behaviors and altered appetite
• Trazodone may help with agitation, aggression and sleeping difficulties
• Antipsychotic medications can also help with some of the behavioural symptoms

These medications have been successful in alleviating some of the symptoms experienced by those with bvFTD.⁸ Additionally, there are non-medication options which can support you, such as occupational therapy.

Summary

• Frontotemporal dementia describes a class of neurodegenerative diseases which primarily affect the frontal and temporal lobes of the brain
• bvFTD is a form of frontotemporal dementia which has profound effects on someone’s behaviour and interpersonal relationships
• Signs of bvFTD include disinhibition, apathy, changes in appetite, stereotypic behaviour, blunted affect and sometimes memory problems
• The symptoms of bvFTD are caused by the accumulation of proteins in brain cells
• There is no definitive test for bvFTD, so the diagnostic process can be long
• Getting an accurate diagnosis is important for deciding the most effective treatment method
• Pharmacological treatment options include antipsychotics, SSRIs, trazodone and others