Could a routine blood test improve dementia outcomes?

Morgan Liotta

6/07/2021 3:53:21 PM

Researchers are hoping a simple blood protein point-of-care test will aid early detection of cognitive impairment.

Patient getting a blood test.
Researchers want a routine diagnostic screening test for dementia and other cognitive conditions to be available in the primary care setting.

Dementia is the second leading cause of death in Australia.
Currently, there is an estimated 472,000 Australians living with the condition, and that number is expected to double to more than one million by 2056.
To help ensure early and timely diagnosis, researchers from the Royal Melbourne Hospital (RMH) are exploring blood biomarkers for people with cognitive, psychiatric and neurological symptoms through the Markers in Neuropsychiatric Disorders (MiND) Study.
Dr Dhamidhu Eratne, the study’s chief investigator and a consultant neuropsychiatrist at the RMH, told newsGP the goal of the research is to lead to routine, clinically-available blood tests for GPs and other specialists.
‘[The tests would] reduce the delay to diagnosis of dementia and other neurological and neurodegenerative disorders,’ he said. ‘And improve outcomes for people with cognitive, psychiatric and/or neurological symptoms, their families, clinicians and healthcare systems.’
Early findings from the MiND Study show that levels of the brain cell protein neurofilament light (NfL) are a marker of neuronal injury and can indicate whether someone has dementia.
This is the first time Australian researchers have established a link between NfL levels and cognitive impairment.
‘NfL levels are much higher in neurodegenerative disorders compared to primary psychiatric and non-neurodegenerative disorders,’ Dr Eratne said.
‘These distinguish neurodegenerative from primary psychiatric causes of cognitive, neurological and psychiatric/behavioural symptoms with very high, more than 90%, accuracy. Thus showing great promise for a screening test to reduce diagnostic delay and improve outcomes.’
Dr Eratne said these findings are significant, given that timely and accurate diagnosis of neurodegenerative disorders, as well as differentiating from primary psychiatric and non-neurodegenerative causes, can be challenging in clinical practice.
‘Especially in younger people and in early stages of neurodegenerative illnesses,’ he said.
‘For example, common challenges include distinguishing Alzheimer’s disease from depression or a “depressive pseudodementia” or differentiating behavioural variant frontotemporal dementia from bipolar disorder.
‘Many patients go through a “diagnostic odyssey”, characterised by many years of multiple assessments and repeated and costly investigations, misdiagnosis, uncertainty, stress, frustration, and needless to say, negative outcomes.’
Professor Dennis Velakoulis, MiND Study lead and Director of Neuropsychiatry at the RMH, agrees that diagnosis can be challenging.
‘In many situations, the blood tests, the brain scans, even the memory testing, can be close to normal,’ he told the ABC.
‘There are many situations that GPs and [other] specialists face where it’s unclear if someone has a mental health or psychiatric disorder, like depression.
‘People with psychiatric illnesses, or people who are healthy, have normal levels of NfL, because there’s no brain cells dying. But in many neurological disorders, particularly in dementia, there are brain cells that are dying and releasing NfL … so when we see it elevated in the spinal fluid or blood, it indicates that there’s been some brain injury.’
The MiND Study team is anticipating the blood test for NfL will one day be available to GPs across the country and is currently working with the Integrated Mental Health Team at the Department of General Practice at the University of Melbourne.
Headed by Professor Jane Gunn, the mental health team is hoping to recruit patients across general practice in Victoria, while also looking to expand interstate.
Dr Eratne said the ‘secondary objectives’ of the study are to build strong relationships with general practice by setting up a platform to support cross-disciplinary collaboration and opportunities for broad biomarker and clinical, cognitive and psychosocial research.

‘The study is aiming for clinical translation by demonstrating the diagnostic, clinical and health economic utility of a blood test for NfL,’ he said.
‘We need help from GPs with referring eligible patients ­− we have very broad eligibility criteria­ ­− so we can understand how this test performs in a primary care setting, feasibility, and how this could be implemented in primary care and other settings.’
Acknowledging GPs’ numerous existing commitments, Dr Eratne said their involvement is kept as ‘simple as possible’, with the minimum requirement being completion of a brief, two-minute referral form. But GPs who would like to be more involved in the MiND Study are welcome.
‘The first step is recruiting patients and getting the data,’ Dr Eratne said.
‘Regarding the next step of actual implementation, we see this as being available as a routine diagnostic screening test, akin to a C-reactive protein or prostate-specific antigen “for the brain” to tell if something neurological is going on for people with cognitive, neurological and/or psychiatric symptoms.
‘This would be similar to testing full blood count and thyroid function as part of dementia screening.’
The MiND Study also has a role in preventive health via early intervention approaches.
‘We anticipate that one day in the future, this could even be a test that could be done periodically,’ Dr Eratne said.
‘Similar to cardiovascular risk factor monitoring, such as lipid monitoring, as a way of predicting future risk and therefore intervening prior to the onset of clinical symptoms when interventions are more likely to be more effective, and preventing the development of illness/clinical symptoms.’

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