Frontotemporal dementia, a rare disease that accounts for only one in every 20 cases of dementia, gained attention earlier this year when actor Bruce Willis announced his diagnosis. This form of dementia typically emerges in a person’s late 50s and initially affects their behavior, personality, and language abilities. Unlike other types of dementia, memory impairment occurs only in the final stages of the disease. Unfortunately, frontotemporal dementia dramatically reduces life expectancy, with patients typically surviving for only eight years following diagnosis. At present, there are no known cures or treatments that can slow down its progression. However, recent groundbreaking research published by our team at Lund University, in collaboration with colleagues in the US and Amsterdam, has shed new light on the development and progression of this debilitating condition.
During fetal development, a unique and intricate network of folds forms in the brain. This process occurs as the brain grows within the womb and expands within the skull. These folds, known as sulci, play a crucial role in our cognitive abilities in later life. While there are several folds that develop early in fetal development and can be found in every person’s brain, there is one fold that sometimes forms later in the process – the paracingulate sulcus. However, not everyone possesses this fold, and for those who do, it may be present on one side or both sides of the brain.
Interestingly, the presence of the paracingulate sulcus is associated with significant differences in cognitive abilities. Studies have shown that individuals with the fold on the left side of their brain, but not the right, possess cognitive advantages and perform better on tasks involving control and memory. Recognizing this link between the paracingulate sulcus and cognitive function, our research team focused on studying the role of this brain fold in the context of frontotemporal dementia.
One of the most challenging aspects of frontotemporal dementia is the aggressiveness with which it attacks the frontal lobes of the brain. Particularly, the central portions surrounding the paracingulate sulcus are heavily impacted by this early-onset dementia. To investigate the specific role of the paracingulate sulcus, our team analyzed MRI brain images of 186 individuals diagnosed with frontotemporal dementia. Participants with genetically inherited frontotemporal dementia were excluded from the study, allowing us to focus on non-genetic factors.
The findings of this study were significant. Among the participants, 57% had a paracingulate sulcus on the right side of their brain. Interestingly, those with this additional fold experienced a delay in the onset of symptoms by an average of two and a half years. This delay, although seemingly small, offers a significant reprieve for individuals and their families given the devastating nature of this condition. However, once symptoms manifested, patients with the paracingulate sulcus deteriorated at a faster rate compared to those without the fold, resulting in a shorter overall survival time.
This paradoxical relationship between the paracingulate sulcus and the progression of frontotemporal dementia aligns with the concept of “brain reserve” in neuroscience. Brain reserve refers to the brain’s ability to resist the onset of symptoms before a disease takes hold. However, at a certain point, this protective mechanism becomes overwhelmed, and symptoms emerge. Subsequently, individuals with high brain reserve experience a rapid decline, outpacing those with low brain reserve.
In a similar manner, our research indicates that the presence of the paracingulate sulcus operates as a protective structure, delaying symptom onset but contributing to a faster progression afterward. This groundbreaking revelation marks the first identification of a protective mechanism in the brain that postpones the onset of frontotemporal dementia symptoms.
These findings open up new avenues for potential treatments and interventions to prevent or delay the symptoms of frontotemporal dementia. By uncovering ways to preserve the protective quality of the paracingulate sulcus, researchers may pave the way for the development of novel therapeutic approaches. This could lead to longer and more fulfilling lives for individuals affected by frontotemporal dementia, offering hope to patients and their loved ones in the face of this devastating disease. As we continue to delve deeper into the intricacies of the brain and its complex diseases, we inch closer to a future where frontotemporal dementia is no longer a life sentence, but rather a condition with manageable symptoms and improved quality of life.