Enfeeblement in Elders with Essential Tremor: Characterizing the Phenomenon and Its Role in Caregiver Burden

BACKGROUND: Individuals with essential tremor (ET), a common movement disorder, experience functional impairment, which contributes to burden experienced by their loved ones and caregivers. Some burdened caregivers report their loved ones as seeming debilitated or prematurely old, a concept that we have called enfeeblement. Using the Essential Tremor Enfeeblement Survey (ETES), we seek to characterize enfeeblement in elders with ET and assess its contribution to caregiver burden. METHODS: We administered the ETES (range = 8–40, higher scores indicating more enfeeblement) and other scales to 98 caregivers of individuals with ET. Individuals with ET were also queried regarding tremors, cognitive abilities, and overall health. We then identified demographic and clinical correlates of ETES and modeled the contribution of ETES to caregiver burden (assessed using the Zarit 12-item Burden Interview [ZBI-12]). RESULTS: Mean ETES score was 14.2 ± 6.2 (median = 12.0, range = 8.0–32.0); 26.5% of respondents endorsed at least one of the eight ETES items. Older age, greater tremor severity and disability, more functional and gait disability, more cognitive difficulty, and more depressive symptoms were associated with higher ETES scores. ETES was the strongest contributor to caregiver burden (ZBI-12) and substantially increased the variance explained in models of caregiver burden. DISCUSSION: Enfeeblement seems to describe a previously unexplained component of caregiver burden in elders with ET. The presence of enfeeblement may contribute to greater burden and should be factored into assessments of patient and caregiver needs.