Enfeeblement in Essential Tremor: Development and Validation of a New Psychometric Measure

Abstract

Introduction: Despite a growing body of knowledge regarding essential tremor (ET), past studies have fallen short in capturing the full impact of ET on patients and caregivers. We propose enfeeblement (i.e., having the qualities of being prematurely old, helpless, or debilitated) as a novel clinical outcome measure in ET. Due to the lack of enfeeblement scales for ET in the literature, we developed and validated an enfeeblement scale for ET. Methods: The Essential Tremor Enfeeblement Survey (ETES) consists of eight 5-point Likert-type scale questions and is designed to be a caregiver-reported outcome. Results: Enfeeblement scores showed a floor effect of 15.3%, no ceiling effects, and demonstrated good overall test-retest reliability (intraclass correlation coefficient ¼ 0.73), favorable internal consistency (Cronbach a coefficient ¼ 0.92) and good convergent validity. Conclusion: The ETES has robust properties. Aside from future studies of enfeeblement in ET, enfeeblement should be explored more broadly as a psychometric measure across other neurological disorders.

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

“…The ETES measures enfeeblement (i.e.,having the qualities of being prematurely old, helpless, or debilitated) and is composed of eight questions (see Table 1) to which caregivers reply on a scale of 1–5 (strongly disagree, disagree, neither agree nor disagree, agree, strongly agree), with higher scores indicating more enfeeblement (range 8–40). 26 The ETES has demonstrated good reliability (intraclass correlation coefficient = 0.73) and good convergent validity to a variety of other measures. 26 The modified pETEA is composed of 14 items querying caregivers to rate on a scale of 1 (strongly disagree) to 5 (strongly agree) their loved ones’ embarrassment related to their tremor (e.g., “My relative is embarrassed by the tremor because other people might think that he/she is nervous”), with higher scores indicating higher levels of perceived embarrassment (range 14–70).…”

“…26 The ETES has demonstrated good reliability (intraclass correlation coefficient = 0.73) and good convergent validity to a variety of other measures. 26 The modified pETEA is composed of 14 items querying caregivers to rate on a scale of 1 (strongly disagree) to 5 (strongly agree) their loved ones’ embarrassment related to their tremor (e.g., “My relative is embarrassed by the tremor because other people might think that he/she is nervous”), with higher scores indicating higher levels of perceived embarrassment (range 14–70). 25,27 The pETEA has been shown to be reliable and valid.…”

“…We have begun to conceptualize this overall quality as one of “enfeeblement.” To facilitate studies of enfeeblement in ET, we recently developed and validated a scale, the Essential Tremor Enfeeblement Survey (ETES), to measure enfeeblement in ET. 26…”