Open Access Research article

Quantification of relevance of quality of life assessment for patients with cognitive impairment: the suitability indices

Karine Baumstarck1*, Mohamed Boucekine1, Laurent Boyer1, Valérie Aghababian2, Nathalie Parola3, Françoise Reuter4, Anderson Loundou1, Christophe Lançon3, Jean Pelletier4 and Pascal Auquier1

Author Affiliations

1 EA3279 Self-perceived Health Assessment Research Unit and Department of Public Health, Aix-Marseille University, APHM, Marseille, France

2 EA 3273 Psychology of Cognition, Language, and Emotion Research Centre, Aix-Marseille University, Marseille, France

3 Department of Psychiatry, Sainte-Marguerite University Hospital, 13009 Marseille, France

4 Departments of Neurology and CRMBM CNRS6612, Timone University Hospital, APHM, Marseille, France

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BMC Neurology 2014, 14:78  doi:10.1186/1471-2377-14-78

Published: 8 April 2014

Abstract

Background

The extent to which MS patients with cognitive dysfunction can accurately self-report outcomes has been a crucial issue. The aim of this study was to quantify and compare the relevance of the quality of life (QoL) assessment between two populations with a high occurrence of cognitive dysfunction, specifically in individuals with multiple sclerosis (MS) and in individuals suffering from schizophrenia (SCZ).

Methods

Design: A cross-sectional study was performed using the following inclusion criteria: MS and SCZ patients were diagnosed according to the McDonald criteria and DSM-IV criteria, respectively. Data on sociodemographic (age, gender, education level) and clinical (disease severity, disease duration) factors, QoL (disease-specific questionnaires, MusiQoL and SQoL) and cognitive performance (executive, memory, and attention functions) were collected. Non-impaired and impaired populations were defined according to the French norms. Psychometric properties were compared to those reported in reference populations, which were assessed in the respective validation studies. Suitability indices were provided used to quantitatively compare how the structures in the different populations matched with the initial structure of the questionnaires (reference populations).

Results

One hundred and twenty-four MS patients and 113 SCZ patients were enrolled. Factor analysis was performed on the impaired populations and revealed that the questionnaire structure adequately matched the initial structure of the disease-specific QoL questionnaires. All of the suitability indices of construct and external validity in the non-impaired populations ranged from 70 to 100%.

Conclusions

Our study suggested that cognitive dysfunction did not compromise the reliability or validity of the self-reported QoL questionnaires among subjects with cognitive dysfunction, such as MS and SCZ. Thus, this report may clarify the relevance of using self-reported QoL assessments in clinical practice.

Keywords:
Cognitive impairment; Multiple sclerosis; Schizophrenia; Quality of life; Validity; Reliability; MusiQoL; SQoL