Bruce Willis's Frontotemporal Dementia Is Not the Dementia We Associate with Older Relatives

News of Bruce Willis's frontotemporal dementia (FTD) diagnosis raised fears of a final chapter spent lost in a neurological quagmire. FTD is an unusual, relatively rare form of dementia. We tend to associate dementia with memory loss, but FTD more characteristically involves loss of control over emotions and other cognitive functions. For performers such as Willis, losing the verbal fluency needed to deliver lines is particularly tragic.

Nearly Invincible Action Star Bruce Willis Faces Dementia

An unforgettable presence in action and crime films, Willis seemed invincible, energetic and full of life, almost an "immortal" superhero. With FTD, however, even Willis, currently only 67, may face years of cognitive decline. If the condition follows its typical course, it may involve gradually losing social connections, emotional judgment and control, and an understanding of what is happening and why. Control of bodily functions and general health may also progressively deteriorate.

Most people with dementia lose cognitive abilities through various pathways involving brain shrinkage, disrupted thinking, evident neuropathology, lost neurobehavioral expression and forms of confusion.

Causes and Characteristics of an Unusual Dementia

Frontotemporal dementia (FTD) is unusual for several reasons:

First, it often occurs in relatively young people, with initial symptoms in their 50s or 60s. In most cases there is no genetic or other explanation for its origin, apart from medical bad luck.

Second, early FTD has little effect on overall memory and cognitive ability. Patients struggle to find the next word and speak more slowly as their brains grapple with verbal fluency. Even while memory appears intact, they have difficulty turning emotions and feelings into quick, appropriate actions.

Other dementias may produce profound cognitive losses while preserving social and emotional control and fluent speech more effectively. Consider how much impaired fluency and difficulty regulating emotional responses can affect a famous actor. By all reports, Willis continued his beloved work enthusiastically until diagnosis, and colleagues likely saw him struggling. Unfortunately, reduced self-awareness is an expected consequence of FTD.

Third , and most intriguingly, FTD involves loss of special cortical cells called von Economo neurons within the salience network. This network rapidly detects and evaluates complex thoughts and emotions and uses these neurons to initiate appropriate neurological and physical responses.

Humans share this special von Economo mechanism with great primates, whales, elephants and other social mammals.

When we see, hear or feel something evoking fear, alarm or potential reward, the salience network acts as a gatekeeper. It first evaluates the new or changing situation, then rapidly initiates an emotional and physical response. When I sit with a visibly distressed patient in my office, an empathic alarm sounds in my salience network. My brain and body immediately adjust to initiate appropriate sympathetic responses. Von Economo neurons, which largely die in FTD, are fundamental to this rapid-response sense and complex bodily-signal information system.

Controlled Emotional Responses Are Central to Our Humanity

It is a sad day when we lose controlled emotional responses.

Where other neurological conditions involve loss of specific brain cells, forms of "disuse atrophy" might partly contribute to FTD. We do not know whether this is true of FTD. Scientists have shown that certain computerized brain exercises can sharply increase salience-network activity, associated with improved regulatory control of the autonomic nervous system. This is a major response-mediating target of the network's von Economo neurons.

Interestingly, super-agers who maintain bodily and brain health into their 90s and beyond retain their full complement of von Economo neurons, working energetically within an active salience network.

Keeping these special neurons alive would likely have allowed Willis to remain on stage, and on life's larger stage, for much longer. As with so much in medicine, this dramatic condition offers lessons and hope for the future. At present, however, the actor's disease is no longer at an early stage, and existing treatment and knowledge are insufficient to substantially improve his condition.

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How Is Dementia Diagnosed?

Diagnosis of FTD and other dementias generally begins with symptoms, medical history and a comprehensive neurological examination. Tests and imaging methods are also commonly needed for accuracy. Nuclear medicine provides advanced imaging technologies that play an important diagnostic role.

1. Neuropsychological tests: These assess memory, language, attention and problem-solving, helping determine dementia severity and which areas are affected.

2. Blood and genetic tests: These may help identify the underlying cause of dementia.

Imaging Methods:

1. Magnetic resonance imaging (MRI): Detailed examination of brain structure helps identify tissue loss and damage.

2. Computed tomography (CT): Scans show brain structure and changes such as atrophy. Atrophy in particular regions is common in FTD and other dementias.

The Importance of Nuclear Medicine:

1. Positron Emission Tomography (PET): PET uses radioactive isotopes to examine brain function. It shows cellular energy use and metabolism and can help identify changes even in early dementia.

   • FDG PET is prominent in diagnosing frontotemporal dementia, while
   • amyloid PET is a leading nuclear imaging method in Alzheimer's dementia.

2. Single-Photon Emission Computed Tomography (SPECT): This nuclear medicine technique visualizes cerebral blood flow and activity, showing patterns characteristic of certain dementias.

Nuclear medicine can support earlier, more accurate diagnosis. These methods may help identify specific dementias such as FTD and assess disease course and treatment response. Early, accurate diagnosis helps patients and families develop better treatment and care plans.

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