Affiliations: [a] Groupe de recherche interdisciplinaire sur les maladies neuromusculaires (GRIMN), CSSS de Jonquière, G7X 7X2 Saguenay, QC, Canada
| [b] Centre de recherche Charles-Le-Moyne, Faculty of Medecine and Health Sciences, Université de Sherbrooke, QC, Canada
| [c] Département des sciences de la santé, Université du Québec à Chicoutimi, Saguenay, QC, Canada
| [d] ÉCOBES – Recherche et transfert, Cégep de Jonquière, Saguenay, QC, Canada
Correspondence to: Benjamin Gallais, Ph.D. Groupe de reche-rche interdisciplinaire sur les maladies neuromusculaires, 2230 de l’Hôpital, cp 1200, Jonquière, G7X 7X2, QC, Canada. Tel.: +1 418 695 7700 (#2786); E-mail: [email protected].
Abstract: Background:Apathy is a common debilitating symptom of myotonic dystrophy type 1 (DM1). The Apathy Evaluation Scale (AES) has been identified as a promising measurement instrument to be used in DM1 but its metrological properties must be further documented. Objective:To determine the internal consistency of the Self (AES-S), Informant (AES-I), and Clinician (AES-C) versions of the AES and to assess the test-retest reliability, standard error of measurement, and minimal detectable change of the AES-S and AES-I in a sample of DM1 patients and their related informants. Results:All scales showed good internal consistency (Cronbach’s alpha: 0.83–0.87) and the AES-S and AES-I showed good test-retest reliability (ICC = 0.79–0.91). Additionally, clinicians and informants had a tendency to overestimate DM1 patients’ level of apathy compared to patients’ self-ratings, suggesting potentially impaired self-awareness in DM1 patients. Conclusions:The present results advocate the use of the AES-I as a reliable instrument to estimate apathy in DM1 patients for either clinical or research purposes, and support the relevance to pursue the assessment of metrological properties of the AES as a tool of great value for the development of outcomes for clinical trial readiness in DM1.