Dementia researchers have called for updates to the diagnostic criteria for one of the most common younger-onset forms of the disease, behavioural variant frontotemporal dementia (bvFTD), a condition similar to the one actor Bruce Willis has been diagnosed with.
Published in Alzheimer's & Dementia , the journal of the US Alzheimer's Association, the study is the most comprehensive review of diagnostic criteria for bvFTD since they were established in 2011.
Using data from 110 patients over 14 years, the study reveals that the current cognitive requirements for diagnosis are "overly restrictive" and could delay access to treatment and clinical trials.
The lead author is Professor Olivier Piguet from the University of Sydney Brain and Mind Centre and the School of Psychology . He said: "Behavioural-variant frontotemporal dementia is a devastating condition that affects personality, empathy and executive function.
"Our findings show that the cognitive criterion - particularly the requirement for preserved memory and visuo-spatial skills - exclude many patients who clearly have this form of dementia. This risks delays in diagnosis and support, especially critical as bvFTD tends to be a younger-onset dementia."
Brain scan of a person with frontotemporal dementia. Source: FRONTIER/USYD
BvFTD is the most common form of frontotemporal dementia, accounting for up to 70 percent of cases. It typically begins with subtle changes in behaviour, such as apathy, disinhibition and loss of empathy. It can then progress to more severe cognitive and functional decline.
Unlike Alzheimer's disease, which primarily affects memory, bvFTD targets the brain's frontal lobes, which govern personality and social behaviour.
The study found that nearly 90 percent of patients presented with empathy loss or apathy, while only 14.5 percent met the strict cognitive criterion currently required for diagnoses. These included memory and visuo-spatial skills.
When the researchers broadened the definition to include executive dysfunction, regardless of memory and visuo-spatial performance, qualifying patients rose to 73 percent.
"This research shows that the behavioural symptoms - such as empathy loss and apathy - are far more consistent and reliable indicators for bvFTD than current cognitive benchmarks," Professor Piguet said.
"We propose removing the requirement for preserved memory and visuo-spatial skills, and adding social cognition as a core diagnostic feature."
"Our hope is that this research will lead to earlier and more accurate diagnoses, better support for families and improved access to emerging therapies."
Professor Olivier Piguet Professor of Clinical Neuropsychology
Importantly, the study also found the number or combination of diagnostic criteria did not predict disease progression or survival. The average survival time from symptom onset was 10.4 years, with women experiencing slightly shorter survival times than men.
The research was conducted through FRONTIER , the University of Sydney's frontotemporal dementia research clinic. It highlights the need for more inclusive diagnostic tools, especially for culturally and linguistically diverse populations.
"Bruce Willis's diagnosis has brought global attention to frontotemporal dementia," Professor Piguet said. "Our hope is that this research will lead to earlier and more accurate diagnoses, better support for families and improved access to emerging therapies."
Research
Piguet, O. et al 'Fourteen years later: reviewing the diagnostic criteria for behaviouralvariant frontotemporal dementia' ( Alzheimer's and Dementia 2025) DOI: 10.1002/alz.70604
Declaration
The authors declare no competing interests. Funding was received from ForeFront, a collaborative research group dedicated to the study of frontotemporal dementia and motor neuron disease; the National Health and Medical Research Council (NHMRC); the Australian Research Council (ARC); and the US Alzheimer's Association.
