Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and...

The subjective dimension of disability, the perception of disability, is a dimension missing from the International Classification of Functioning, Disability and Health (ICF), and from health-related quality of life (HRQOL) instruments. However, it is a highly relevant dimension for clinical practice as perceived disability may identify care needs. We therefore developed a measure for this subjective dimension of disability in multiple sclerosis (MS) and examined the contribution of this dimension to QOL.

A measure named the Multiple Sclerosis Impact Profile-Disability Perception (MSIP-DP) was developed to reflect a person's perception of disabilities reported using the original MSIP-disability (MSIP-D) items. MS patients (n=530) completed both MSIP sections, the medical outcome study short form questionnaire (SF-36), the World Health Organisation Quality Of Life-BREF (WHOQOL-BREF) and questions concerning disease severity. The contribution of disability perception (DP) to QOL in MS was estimated using hierarchical multiple regression analyses after controlling for MS severity.

Confirmative factor analysis confirmed the hypothesised disability perception domains that correspond with the related disability domains in the MSIP. DP scales yielded sufficient reliability. DP explained a unique and substantial part of the variance in QOL, particularly the perception of impairments in mental functions.

Results indicated that the subjective dimension of functioning and health operationalised in the MSIP-DP is a relevant concept in explaining QOL in MS. In clinical practice psychological interventions addressing a patient's perception of disability, particularly of impairments in mental functioning, may contribute to QOL.