PROJECT SUMMARY/ABSTRACT Socioemotional impairments are core features of behavioral variant of Frontotemporal Dementia (bvFTD) and account for the majority of disease related morbidity. bvFTD patients also demonstrate autonomic impairments and these likely account for several socioemotional deficits in this condition. However, efforts to characterize autonomic dysfunction in bvFTD patients remain sparse, and the reliability of such measures remains undetermined. The characterization of autonomic dysfunction in bvFTD would be greatly advanced by novel technologies that measure autonomic function more consistently and in patients’ home environments. Such technologies include wearable garments and smartwatches capable of serially recording heart-rate variability, electrodermal activity, pupil reactivity and others. This proposal will first assess the test-retest reliability of “gold-standard” measurements of autonomic function in 30 bvFTD patients and in 30 matched controls in a controlled laboratory setting. This will establish that bvFTD patients have detectable and stable autonomic impairments when compared to controls. It will then assess the test-retest reliability of ambulatory wearable technologies in the same laboratory environment in both groups and will correlate gold-standard and ambulatory metrics to establish the validity of the ambulatory measures. Next, it will assess the feasibility of using ambulatory autonomic assessments in both subject groups at home. Finally, it will correlate gold- standard and ambulatory autonomic measurements to validated ratings of socioemotional function. This work will germinate studies establishing autonomic metrics as predictive biomarkers of socioemotional dysfunction in bvFTD. It will also vastly advance our understanding of the neurobiological basis of autonomic dysfunction and socioemotional impairment in bvFTD.