Reducing sample size requirements for future ALS clinical trials with a dedicated electrical impedance myography system.
Amyotroph Lateral Scler Frontotemporal Degener
; 19(7-8): 555-561, 2018 11.
Article
em En
| MEDLINE
| ID: mdl-30265154
ABSTRACT
OBJECTIVE:
In this longitudinal multicenter cohort study, we evaluated the potential of a dedicated electrical impedance myography (EIM) device to assess ALS progression and the system's basic reproducibility and diagnostic accuracy.METHODS:
Forty-six ALS patients underwent up to five sequential measurements of multiple muscles over a period of 8 months at 2-month intervals using the mView EIM device (Myolex, Inc., San Francisco, CA). Standard measures of disease status were also obtained. A group of 30 healthy volunteers and 30 ALS-mimics were evaluated once to determine if the technique could assist with initial diagnosis. Several electrode arrays and EIM outcomes were assessed.RESULTS:
EIM tracked ALS progression; power analyses suggested a 5.2-fold reduction in sample size requirements compared to ALSFRS-R by utilizing 50 kHz phase value from the muscle with the greatest EIM decline in each subject. This progression rate correlated to total ALSFRS-R progression, with R = 0.371, p = 0.021. Reproducibility was high, with both intra- and inter-rater intraclass correlation coefficients for individual muscles mostly greater than 0.90. The mean 50 kHz phase distinguished between ALS patients and healthy controls (area-under-curve 0.78, 95% confidence intervals (CIs) 0.68, 0.89), but not between mimics and ALS patients (area-under-curve 0.60, 95% CIs 0.47, 0.73).CONCLUSIONS:
While limited in its specificity to identify ALS versus disease mimics, these results support the hypothesis that single-muscle EIM can serve as a convenient, repeatable, and powerful outcome measure in ALS clinical trials.Palavras-chave
Texto completo:
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Impedância Elétrica
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Tamanho da Amostra
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Músculo Esquelético
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Potencial Evocado Motor
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Miografia
Tipo de estudo:
Clinical_trials
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Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Amyotroph Lateral Scler Frontotemporal Degener
Ano de publicação:
2018
Tipo de documento:
Article