TMS for staging and predicting functional decline in frontotemporal dementia.

Area of Science:

• Neuroscience
• Neurology
• Neurophysiology

Background:

• Frontotemporal dementia (FTD) encompasses several neurodegenerative disorders.
• Understanding FTD progression and identifying reliable biomarkers are crucial for patient management.
• Current markers for FTD severity and progression may not fully capture disease dynamics.

Purpose of the Study:

• To assess the correlation between transcranial magnetic stimulation (TMS) measures and FTD disease severity.
• To determine if TMS measures can predict functional decline in FTD patients over a 12-month period.
• To identify the most effective neurophysiological marker for predicting FTD progression.

Main Methods:

• Paired-pulse TMS was employed to examine intracortical circuit activity in 171 FTD patients and 74 controls.
• Pearson's correlations analyzed the association between TMS measures and disease severity (FTLD-CDR).
• Multiple regression identified predictors of 12-month functional decline (change in FTLD-CDR scores).

Main Results:

• Significant correlations were found between TMS measures (SICI-ICF, LICI) and FTD disease severity (r > 0.5, p < 0.005).
• SICI-ICF, SICF, and LICI predicted functional decline over 12 months (p < 0.005).
• Short-interval intracortical inhibition (SICI) was the strongest predictor of disease progression, explaining 72.5% of the variance in FTLD-CDR scores at 12 months (adjusted R² = 0.72, p < 0.001).

Conclusions:

• Dysfunction in inhibitory and facilitatory intracortical circuits, as measured by TMS, is strongly linked to FTD severity.
• TMS measures, particularly SICI, serve as robust predictors of functional decline in FTD.
• TMS offers a promising neurophysiological tool for monitoring FTD progression and predicting outcomes.