Validation of a New Patient-Reported Outcome Measure of the Functional Impact of Essential Tremor on Activities of Daily Living

Ludy C Shih; Michael T Stevenson; Steven Bellows; Alfonso Fasano; Sheng-Han Kuo; Kelly E Lyons; Henry Moore; Holly A Shill; Aparna Wagle Shukla; Carlos Singer; Rodger J Elble

doi:10.5334/tohm.886

Validation of a New Patient-Reported Outcome Measure of the Functional Impact of Essential Tremor on Activities of Daily Living

Tremor Other Hyperkinet Mov (N Y). 2024 May 14:14:26. doi: 10.5334/tohm.886. eCollection 2024.

Authors

Ludy C Shih^{1

2}, Michael T Stevenson³, Steven Bellows⁴, Alfonso Fasano^{5

6

7}, Sheng-Han Kuo⁸, Kelly E Lyons⁹, Henry Moore¹⁰, Holly A Shill¹¹, Aparna Wagle Shukla¹², Carlos Singer¹⁰, Rodger J Elble¹³

Affiliations

¹ Beth Israel Deaconess Medical Center, Department of Neurology, Boston, MA 02215, US.
² Harvard Medical School, Boston, MA 02215, US.
³ Boston Medical Center, Department of Neurology, Boston, MA 02118, US.
⁴ Baylor College of Medicine, Department of Neurology, Houston, TX, US.
⁵ Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada.
⁶ Division of Neurology, University of Toronto, Toronto, Ontario, Canada.
⁷ Krembil Brain Institute, Toronto, Ontario, Canada.
⁸ Columbia University, Department of Neurology, New York, NY, US.
⁹ University of Kansas Medical Center, Department of Neurology, US.
¹⁰ University of Miami School of Medicine, Department of Neurology, Miami, FL, US.
¹¹ Barrow Neurological Institute, Phoenix, AZ, US.
¹² Fixel Institute for Neurological Diseases, University of Florida, Department of Neurology, Gainesville, FL, US.
¹³ Southern Illinois University School of Medicine, Department of Neurology, Springfield, IL, US.

Abstract

Background: The Essential Tremor Rating Assessment Scale (TETRAS) is a popular scale for essential tremor (ET), but its activities of daily living (ADL) and performance (P) subscales are based on a structured interview and physical exam. No patient-reported outcome (PRO) scale for ET has been developed according to US regulatory guidelines.

Objective: Develop and validate a TETRAS PRO subscale.

Methods: Fourteen items, rated 0-4, were derived from TETRAS ADL and structured cognitive interviews of 18 ET patients. Convergent validity analyses of TETRAS PRO versus TETRAS ADL, TETRAS-P, and the Quality of Life in Essential Tremor Questionnaire (QUEST) were computed for 67 adults with ET or ET plus. Test-retest reliability was computed at intervals of 1 and 30 days. The influence of mood (Hospital Anxiety and Depression Scale, HADS) and coping behaviors (Essen Coping Questionnaire, ECQ) was examined with multiple linear regression.

Results: TETRAS PRO was strongly correlated (r > 0.7) with TETRAS ADL, TETRAS-P, and QUEST and exhibited good to excellent reliability (Cronbach alpha 95%CI = 0.853-0.926; 30-day test-retest intraclass correlation 95%CI = 0.814-0.921). The 30-day estimate of minimum detectable change (MDC) was 6.6 (95%CI 5.2-8.0). TETRAS-P (r_semipartial = 0.607), HADS depression (r_semipartial = 0.384), and the coping strategy of information seeking and exchange of experiences (r_semipartial = 0.176) contributed statistically to TETRAS PRO in a multiple linear regression (R² = 0.67).

Conclusions: TETRAS PRO is a valid and reliable scale that is influenced strongly by tremor severity, moderately by mood (depression), and minimally by coping skills. The MDC for TETRAS PRO is probably sufficient to detect clinically important change.

Keywords: anxiety; coping skills; depression; essential tremor; patient-reported outcome measure.

Publication types

Validation Study

MeSH terms

Activities of Daily Living*
Adult
Aged
Aged, 80 and over
Essential Tremor* / diagnosis
Essential Tremor* / physiopathology
Essential Tremor* / psychology
Female
Humans
Male
Middle Aged
Patient Reported Outcome Measures*
Quality of Life
Reproducibility of Results
Surveys and Questionnaires

Grants and funding

The Essential Tremor Rating Assessment Scale is copyrighted by the Tremor Research Group. All authors received grant funding from Tremor Research Group to conduct this study. RJE received additional funding from the Kiwanis Neuroscience Research Foundation, Illinois-Eastern Iowa District of Kiwanis International.