Symptomatic conversion in a case of sporadic frontotemporal dementia: Longitudinal neuroimaging of the presymptomatic stage.

BACKGROUND

Identifying preclinical stages of behavioral variant frontotemporal dementia (bvFTD) is exclusively possible in familial bvFTD. In non-genetic (sporadic) cases this is prevented by the lack of biomarkers. In particular, serial neuroimaging might preview early abnormalities in asymptomatic genetic bvFTD, whereas such data are lacking in sporadic bvFTD.

CASE: Here, we present a pathology-confirmed case of sporadic bvFTD in a 61-year-old male with the unique availability of multiple presymptomatic magnetic resonance imaging (MRI) scans following a resection of meningioma 20 years prior to disease onset. This study aims to provide a detailed description of his clinical disease course, symptom onset, and early cortical changes on MRI using visual rating scales (VRS), as well as post-mortem evaluation.

METHODS

Eight T1-weighted MRI scans (2000-2023) were assessed using previously developed and validated VRS, scored for both hemispheres separately by two independent raters (DML, and GGF). The scales used were: Anterior cingulate (AC), orbitofrontal (OF), frontoinsular (FI), anterior temporal (AT), medio-temporal atrophy (MTA), and posterior atrophy (PA). Four MRI scans were available in the presymptomatic stage, and four after reported symptom onset in 2016. Clinical data was collected from medical charts, and a structured retrospective interview with the patient's family and caregivers.

CONCLUSIONS

In this case of sporadic bvFTD due to Pick's disease, structural changes in frontoinsular and anterior temporal cortices preceded symptom onset by 5-9 years. Exploring patient populations with repeated follow-up imaging, particularly outside of dementia clinics, could provide valuable insights into longitudinal changes in neurodegenerative diseases.