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Behavioral Variant Frontotemporal Dementia (bvFTD)

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Behavioral variant frontotemporal dementia (bvFTD) is the most prevalent form of FTD, accounting for roughly half of all cases. It is sometimes also called frontotemporal dementia or Pick’s disease. BvFTD is primarily characterized by changes in personality, apathy, and a gradual deterioration in socially appropriate behavior, judgment, self-control, and empathy. Unlike Alzheimer’s disease, memory is often relatively preserved in bvFTD. Individuals with bvFTD may be unaware of the changes in their behavior and typically show little concern for how their actions affect those around them.

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Symptoms of bvFTD can sometimes overlap with other FTD-related disorders where motor symptoms dominate, such as progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), and the ALS–FTD spectrum disorder (ALS-FTSD).

​Recognizing the Signs and Symptoms of bvFTD

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Disinhibition
A marked reduction in social restraint can lead to impulsive or inappropriate behaviors, such as:

  • Making rude or offensive remarks

  • Invading personal space

  • Shoplifting or reckless spending

  • Inappropriate sexual behavior or touching strangers

  • Aggressive outbursts

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Apathy
A lack of motivation or interest in activities once considered meaningful, which may appear as:

  • Neglect of work, hobbies, and personal relationships

  • Poor personal hygiene

  • Loss of initiative

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Emotional Blunting
Reduced emotional responsiveness, warmth, or empathy, such as:

  • Indifference to significant life events (e.g., a loved one’s death)

  • Failure to notice or respond to others’ distress

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Compulsive or Ritualistic Behaviors
Repetitive actions or routines may include:

  • Repeating words or phrases

  • Hand rubbing or clapping

  • Re-reading the same book repeatedly

  • Hoarding items

  • Walking the same route daily

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Changes in Eating Habits or Diet
Marked alterations in eating or drinking patterns, which can include:

  • Binge eating or carbohydrate cravings

  • Preference for very specific foods

  • Increased or new use of tobacco

  • Excessive consumption of water or alcohol

  • Attempting to eat non-food items (hyperorality)

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Executive Function Deficits
Challenges with planning, problem-solving, decision-making, and organization, such as:

  • Difficulty scheduling daily activities

  • Poor financial decisions

  • Uncharacteristic mistakes at work

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Other Symptoms
Emotional instability or agitation, often expressed through:

  • Pacing

  • Abrupt mood changes

  • Lack of insight into personal behavior

  • Blaming others for the consequences of inappropriate actions

  • Frustration when activities are limited

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Primary Progressive Aphasia(PPA)

Primary Progressive Aphasia (PPA) is characterized predominantly by the gradual loss of the ability to speak, read, write, and understand what others are saying.

PPA is diagnosed when three criteria are met:

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  1. There is a gradual impairment of language (not just speech)

  2. The language problem is initially the only impairment

  3. The underlying cause is a neurodegenerative disease

 

Experts further subdivide PPA into three clinical subtypes based on the specific language skills that are most affected.
 

Nonfluent/Agrammatic variant 

Nonfluent/agrammatic PPA (nfvPPA) affects speech while leaving single-word understanding mostly intact. People may speak slowly and with effort due to apraxia of speech, and make grammatical errors, omitting small words or mis ordering sentences (agrammatism). Over time, they may struggle with complex sentences, develop swallowing difficulties, and show movement problems similar to Parkinson’s disease. In later stages, speech can be lost entirely.

 

Semantic variant

Semantic variant PPA (svPPA), also called PPA-S, primarily affects the understanding of words, while speech production and repetition remain intact. People with svPPA may speak fluently, but their language becomes vague as words are forgotten or substituted. Early signs include anomia (difficulty naming objects) and loss of single-word meaning, with later stages sometimes showing impaired object knowledge and surface dyslexia/dysgraphia. Behavioral changes similar to bvFTD, such as disinhibition or rigid food preferences, can also appear.

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svPPA is progressive and currently has no cure. Management focuses on caregiver education, communication strategies, and addressing behavioral symptoms with supportive interventions or medications like SSRIs when appropriate.

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Logopenic variant

Logopenic variant PPA (lvPPA or PPA-L) primarily affects word retrieval, causing speech to be slow and hesitant when searching for specific or unfamiliar words. Unlike semantic PPA, word meanings are preserved, and unlike agrammatic PPA, speech is generally fluent and not effortful. Individuals may also have difficulty repeating longer phrases and may make phonological errors (sound substitutions or omissions). Comprehension of complex sentences can decline over time, and swallowing problems may develop in later stages.

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Diagnosis is based on difficulty finding words and impaired repetition, often with intact single-word comprehension, correct grammar, and normal motor speech. There is currently no cure; management focuses on speech-language evaluation, monitoring progression, and supporting independence and communication.

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FTD-ALS 

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In 2011, researchers identified a variant in the C9orf72 gene as the most common cause of both genetic FTD and genetic amyotrophic lateral sclerosis (ALS). Previously, ALS was thought to be purely a movement disorder, while FTD was considered purely a cognitive or behavioral form of dementia.

FTD and ALS can occur in the same person, a clinical subtype known as FTD-ALS. Describing this unique clinical syndrome has been an area of active research, and our knowledge of its underlying genetics, pathology, and clinical features is increasing.

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The current understanding of ALS with language deficits is still incomplete. Both the nonfluent agrammatic variant and the semantic variant of primary progressive aphasia, an FTD disorder that affects language, have been reported in association with ALS.

FTD-ALS Symptoms

 

In individuals with FTD-ALS, signs of a frontotemporal dementia disorder, most often behavioral variant FTD typically appear first, manifesting as changes in personality, behavior, and language.

 

Motor difficulties commonly linked to ALS, such as problems with walking, swallowing, or hand movements, tend to develop later.

 

Cognitive and behavioral changes arise from degeneration of the brain’s frontal and temporal lobes, while the motor symptoms result from nerve deterioration in the spinal cord that controls muscles throughout the body.

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Progressive Supranuclear Palsy

 

Progressive supranuclear palsy (PSP) belongs to the category of FTD disorders that primarily affect movement. Some symptoms of both PSP and corticobasal syndrome, another FTD disorder associated with a decline in motor function resembling those often seen in people with Parkinson’s disease. In fact, these features are sometimes referred to as “atypical Parkinsonism.”

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The earliest motor symptoms are stiffness in the axial muscles, the neck and trunk, along with poor balance and more frequent falls. The earliest visual signs are a decrease in upward vertical movement of the eyes (vertical saccades) and a progressive inability to move the eyes, including opening or closing the eyes. PSP can also affect coordination, and movement of the mouth, tongue, and throat. In addition to motor symptoms, people with PSP may exhibit changes in behavior and language skills common to bvFTD and PPA, particularly as the disease progresses.

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​Know the Signs…Know the Symptoms

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Supranuclear gaze palsies

The person affected may experience an inability to move or aim the eyes vertically (particularly downward) or horizontally (left and right). They may experience rapid involuntary eye movements, or difficulty blinking or excessive blinking. Supranuclear gaze palsies may be experienced as blurring. The person affected may experience difficulty reading, make poor eye contact during conversations, have difficulty going down stairs, or experience impaired vision while driving.

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Postural instability

Difficulty maintaining balance, which can lead to frequent, unexplained falls

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Gait instability

An unsteady, awkward gait

Akinesia/bradykinesia

Absence of movement (akinesia) or abnormally slow (bradykinesia) movement

Rigidity

Stiffness, resistance to movement

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Dysphagia

Difficulty swallowing, including gagging or choking. This can lead to aspiration pneumonia.

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Dysarthria

Slurred or slowed speech due to difficulty moving the muscles controlling the lips, tongue and jaw.

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Behavioral and emotional symptoms that may occur in PSP

A progressive deterioration in the diagnosed person’s ability to control or adjust their behavior appropriately in different social contexts is the hallmark of the behavior changes, and results in the embarrassing, inappropriate social situations that can be one of the most disturbing facets of FTD and related disorders.

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In addition to the depression, apathy and inability to control emotions noted above, PSP patients may manifest emotional blunting or indifference toward others and a lack of insight into changes in their own behavior.

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Cognitive symptoms

PSP patients may suffer increasing impairment in “executive functions,” such as distractibility, mental rigidity and inflexibility, impairments in planning and problem solving, and poor financial judgment. PSP patients may also have memory problems. They also develop progressive language disturbance.

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Diagnosis

Based on overlapping symptoms, PSP is frequently misdiagnosed as Parkinson’s or another movement disorder.  Some symptoms, especially the potential behavioral and cognitive ones may appear later in the progression of the disease. If you have concern that you or a loved one may have been misdiagnosed or about any of the signs and symptoms listed above it is important to consult a doctor.

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Corticobasal Syndrome (CBS)

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Corticobasal syndrome (CBS) is a type of FTD disorder that primarily impacts movement. Some of its motor symptoms resemble those seen in Parkinson’s disease, a pattern often called “atypical Parkinsonism,” and are shared with progressive supranuclear palsy, another motor-dominant FTD disorder.

 

In CBS, movement problems usually begin on one side of the body but eventually affect both sides. Over time, behavioral changes and language difficulties similar to those seen in bvFTD and PPA may also appear.

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CBS is linked to degeneration in the frontal and temporal lobes, as well as deeper brain regions responsible for initiating, coordinating, and controlling movement. The term corticobasal degeneration (CBD) refers to cases confirmed at autopsy with a specific tau pathology, though some CBS cases show Alzheimer’s-related changes instead.

Common Symptoms of CBS:

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Limb Apraxia

Difficulty performing intended movements with a hand, arm, or leg, despite normal muscle strength; challenges with daily tasks like using tools or opening doors.

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Akinesia/Bradykinesia

Absent or unusually slow movement

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Rigidity

Stiffness or resistance to movement

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Dystonia

Involuntary twisting or abnormal positioning of a limb due to muscle contraction

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Cognitive Effects

  • Alien Limb Phenomenon: Feeling that a limb does not belong to the body and inability to control its movements

  • Acalculia: Difficulty performing simple calculations

 

Visuospatial Deficits

Trouble understanding spatial orientation or navigating environments

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