Quality of life in Essential Tremor Questionnaire (QUEST): Development and initial validation

Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7025, USA.
Parkinsonism & Related Disorders (Impact Factor: 3.97). 09/2005; 11(6):367-73. DOI: 10.1016/j.parkreldis.2005.05.009
Source: PubMed


Essential tremor (ET) can diminish functioning and quality of life (QOL) but generic QOL measures may be relatively insensitive to ET and its therapies. We sought to develop an ET-specific measure that might be more sensitive, acceptable to patients, relatively brief, and easily used.
A sample of 200 patients (average age 70 years, range 30-91; average disease duration 15 years) rated the extent to which tremor impacts a function or state, tremor severity in various body parts, perceived health, and overall QOL. Responses to this initial questionnaire were subjected to principal components analysis (PCA). Inspection of factor coordinates, Eigenvalues, variance accounted for, and correlation matrices were used to select items for confirmatory PCA. Final scale reliability was assessed using Cronbach's alpha. Validity was evaluated by correlations between QOL scales and self-rated tremor severity.
PCA of 65 initial items yielded 11 factors accounting for 71% of variance. Six factors were discarded. Two items were eliminated for not loading on a factor and 33 for perceived redundancy. Confirmatory PCA of the retained 30 items yielded an almost identical factor structure (six factors, 70% of variance accounted for, and similar item loadings). Because two factors had very few items loading on them, these two factors were combined into one scale. The final measure has five scales: Physical, Psychosocial, Communication, Hobbies/Leisure, and Work/Finance. Reliability was excellent for the whole instrument and four scales (> or =0.89), and good for the Work/Finance scale (0.79). Severity of voice and head tremor were the best correlates of Communication (0.70 and 0.35), while the Physical scale was related to right and left upper extremity tremor (0.59 and 0.56). Scales correlated more highly with patients' rating of their overall QOL than their health perception.
A brief, 30-item, ET-specific QOL scale with excellent reliability was developed. Preliminary validity data are encouraging. The Quality of Life in Essential Tremor Questionnaire (QUEST) promises to facilitate QOL measurement in ET.

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Available from: Alexander Troster, Aug 20, 2015
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    • "Although the SF-36 scale for assessing quality of life is valid and widely used,41 the Questionnaire for Essential Tremor (QUEST) is a newer, more specific assessment of quality of life changes associated with ET. Developed in 2005 by Tröster et al.,42 QUEST was designed as a clinical tool for correlating changes in 30 aspects of tremor severity, social and personal disability, and perception of health. An independent validation study of the QUEST performed by Martinez-Martin et al.43 concluded that most of the psychometric parameters were found to be satisfactory in their ability to assess the impact of ET on the patients' quality of life. "
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    ABSTRACT: Essential tremor (ET) is one of the most common tremor disorders in the world. Despite this, only two medications have received Level A recommendations from the American Academy of Neurology to treat it (primidone and propranolol). Even though these medications provide relief to a large group of ET patients, up to 50% of patients are non-responders. Additional medications to treat ET are needed. This review discusses some of the methodological issues that should be addressed for quality clinical drug development in ET.
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    • "It occurs in approximately 4.0% of individuals aged 40 years and older (Dogu et al., 2003) and its prevalence continues to rise with age, with prevalence estimates of 21.7% among persons aged 95 years and older (Louis et al., 2009c). The tremor is often progressive (Critchley, 1949) and patients may experience difficulties performing basic daily activities (Busenbark et al., 1991; Bain et al., 1994; Louis et al., 2001), thereby impairing quality of life (Troster et al., 2005). In addition to action tremor, patients may also have intention tremor (Louis et al., 2009b), rest tremor (Cohen et al., 2003), and other motor signs, including ataxia (Singer et al., 1994). "
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    ABSTRACT: Background: Essential tremor (ET) is one of the most common neurological diseases. Although a large number of medications have been tested, there are only two first-line medications, primidone and propranolol, which is a situation that has not changed in approximately 30 years. Several recent reviews have summarized the current pharmacotherapeutic options for ET and the approach to the management of ET patients. Yet there remain a number of important issues, both scientific and clinical, that have not been broached in the literature and that have therapeutic implications. Objectives: To introduce several clinical and scientific issues that have not formally entered the published literature on the treatment of ET. Methods: In September 2011, materials for this article were gathered during a literature search of PubMed using the following terms: ET, clinical, clinical trial, treatment, medications, therapeutics. English-language articles were selected for further review. Results: The paper focuses on several topics that have received scant or no discussion in the published literature on ET therapeutics. These topics are as follows: the nature of the underlying disease pathophysiology, the presence of pathological heterogeneity, the complexity of cellular and neurochemical changes which may be underlying this disorder, the presence of clinical heterogeneity, the selection of treatment endpoints, the effects of diagnostic uncertainty, the presence of cognitive and psychiatric features in ET, the identification of possible modifiable risk factors, and the absence of any neuroprotective therapies. Conclusion: The author has identified several topics that have received scant or no discussion in the published literature on ET therapeutics. Further discussion of the issues raised here may lead to improvements in clinical trial methodologies as well as facilitate the development of fresh approaches to pharmacotherapy.
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    ABSTRACT: To determine the effect of ventral intermedius (VIM) deep brain stimulation (DBS) on health-related quality of life (HRQoL) in essential tremor (ET) patients using disease-specific instruments. Several studies have concluded that DBS improves motor function in medically-refractory ET patients; less emphasis has been placed on HRQoL measures. Generic HRQoL scales are multidimensional questionnaires that cover a wide variety of areas and can be applied to many diseases, but may lack sensitivity in areas important to ET, such as tremor or social embarrassment. . ET patients who underwent VIM-DBS were assessed prospectively using several clinical scales at baseline and 6 months after implantation: Tremor Rating Scale (TRS), Quality of Life in Essential Tremor Questionnaire (QUEST), Questions on Life Satisfaction Module (QLSm), Mini-Mental Status Examination (MMSE), and Geriatric Depression Scale (GDS). At total of 7 patients (4 male), age 67.9 ± 13.9 years, consented to be enrolled in this study. The TRS improved by 65.3% (p<0.001) from baseline to 6 months (Table 1). Three portions of the QLSm improved significantly including QoL in relationship to leisure activities/hobbies, controllability/fluidity of movement, and hand dexterity (Table 2 & 3). The total QUEST score improved from 39.3 ± 6.2 to 13.0 ± 6.4 (p=0.004). On average, patients were "moderately to very satisfied" with several variables related to the neurostimulator: reliability, inconspicuousness, manipulation, and absence of false bodily sensations. Depression improved significantly while MMSE scores did not changed appreciably. Improvements in motor function for ET patients undergoing VIM-DBS translate into improved QoL using disease-specific clinical scales.
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