2291 Plasma neurofilament light chain and clinical diagnosis in frontotemporal dementia syndromes

• Published in: BMJ neurology open Vol. 4; no. Suppl 1; pp. A31 - A32
• Main Authors: Ooi, Suyi, Darby, David, Eratne, Dhamidhu, Patel, Sheila K, Kyndt, Christopher, Reidy, Natalie, Lewis, Courtney, Lee, Sarah CM, Brodtmann, Amy
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.08.2022; BMJ Publishing Group LTD
• Subjects: Abstracts; Dementia; Motor neurone disease; Plasma; Semantics
• ISSN: 2632-6140
• DOI: 10.1136/bmjno-2022-ANZAN.82

ObjectiveTo study plasma NfL levels in people with frontotemporal dementia (FTD) syndromes and determine if plasma NfL can distinguish between FTD syndromes and FTD phenocopy, whom are difficult to clinically distinguish from bvFTD.MethodsPlasma NfL was estimated using two independent Quanterix Simoa machines (a HD-X and SR-X). Participants referred to a tertiary national outpatient cognitive service were characterised into bvFTD, slowly progressive bvFTD (slow progressor), phFTD, motor neuron disease with FTD (FTD-MND), semantic variant FTD (svFTD) and non-fluent variant FTD (nfvFTD). Statistical comparisons were performed using non-parametric tests.ResultsFifty participants, mean age 67.2 (standard deviation 8.4) years and mean follow-up duration of 3.6 (2.4) years were analysed, and 49 patients had a final diagnosis of an FTD syndrome. Plasma NfL was significantly higher in the FTD group compared to phFTD (p = 0.002). There was a trend towards a higher median NfL in bvFTD compared to phFTD (p = 0.14). NfL [median (interquartile range) pg/mL] was comparable in bvFTD [41.10 (50.72), n=20], semantic variant FTD [44.38 (16.61), n=11] and non-fluent variant FTD [42.61 (22.93), n=9]. It was highest in FTD with motor neuron disease [79.67 (45.32), n=4], and lowest in phFTD [13.99 (0.79), n=2] and ‘slow progressors’ [17.97 (3.62), n=3].ConclusionPlasma NfL appears to be able to differentiate subtypes of true FTD from phFTD in this exploratory analysis. Further studies should be undertaken with larger samples of patients from all clinical groups to confirm these findings and establish cut-points for each syndrome.