Striatal dopaminergic patterns and clinical features in frontotemporal dementia

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Frontotemporal dementia (FTD) is a neurodegenerative disorder characterized by behavioral and language impairments.
• Dopamine dysfunction, especially in the caudate nucleus, is increasingly implicated in FTD pathophysiology.
• A deficit in goal-directed behavior, potentially linked to altered frontostriatal dopamine control, is a proposed FTD mechanism.

Purpose of the Study:

• To investigate striatal dopamine transporter (DAT) levels and distribution patterns in FTD using neuroimaging.
• To compare DAT levels in FTD with Parkinson's disease (PD) and healthy controls (HC).
• To explore correlations between DAT uptake and clinical features, including social cognition and language abilities in FTD.

Main Methods:

• ¹²³I-Ioflupane Single Photon Emission Computed Tomography (SPECT) imaging was used to measure DAT levels.
• Participants included 34 FTD patients (22 behavioral variant FTD, 12 primary progressive aphasia), 68 PD patients, and 37 HC.
• Social cognition and language abilities were assessed using standardized neuropsychological tests.

Main Results:

• FTD patients exhibited significantly reduced DAT levels compared to HC (P < 0.001).
• FTD showed a higher putamen-to-caudate DAT ratio than PD (P < 0.001), especially in mutation carriers.
• DAT levels correlated with parkinsonian motor features, general cognition, social cognition (facial emotion recognition), and language abilities in FTD.

Conclusions:

• Striatal DAT uptake patterns may serve as a valuable imaging biomarker for FTD.
• The findings highlight the role of the dopaminergic system and striatum in core FTD clinical features.
• This research opens avenues for investigating dopaminergic mechanisms and therapeutic targets in FTD.