Cognitive impairment in multiple sclerosis does not affect reliability and validity of self-report health measures

Abstract

Patient self-report health measures have received increasing recognition as supplementary outcome parameters in multiple sclerosis (MS). Given the high prevalence of cognitive problems in this population, reliability and validity of self-report instruments in patient groups with cognitive impairment is essential, especially when using such scales longitudinally. A sample of 80 MS patients with cognitive dysfunction according to Symbol Digit Modalities Test (SDMT) score and 107 unimpaired patients were included in the analyses. Data was available from the Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS), the Hospital Anxiety and Depression Scale (HADS), clinical rating scores [Expanded Disability Status Scale (EDSS) and FS (Functional Status) scales, CAMBS (Cambridge MS Basic Score)] and objective tests of upper and lower limb function [Timed 8 Meter Walk (T8) and Nine Hole Peg Test (9HPT)). Both self-report questionnaires showed satisfactory internal consistencies and retest reliability. Pattern and magnitude of correlations with other health status measures supported the validity of both instruments. However, there was a marked discrepancy between subjective and objective measures of cognitive function. Cognitively impaired patients furthermore showed significantly higher depression and anxiety as well as lower quality of life (QoL). The report provides evidence that QoL and affective symptomatology can be reliably assessed in MS patients with cognitive dysfunction. The common pattern of poor correlation between self-rated and objective cognitive function thus appears to be a result of the patients' (adaptive or maladaptive) coping mechanisms rather than being due to inaccurate measurement.

Coping Strategy and Anxiety Evolution in Multiple Sclerosis Patients Initiating Interferon-Beta Treatment

“…Even if cognitive changes can already be present at the beginning of MS [13], we considered them too mild to interfere with coping strategy adoption, and it was reported that cognitive impairment in MS does not affect reliability and validity of self-report health measures [14]. In our study, most patients (53%) adopted a task-oriented coping strategy.…”

Factors Associated with Health-Related Quality of Life Among Older People with Multiple Sclerosis

“…Although according to the SDMT the sample in this study was cognitively impaired, this should not affect their self-report. Gold et al 53 studied cognitively impaired MS patients and their ability to accurately self-report and found that QOL and affective symptomatology can be reliably assessed in MS patients with cognitive impairment. Sprangers et al 54 compared QOL in young, middle-aged, and older people with numerous chronic diseases and found that patients who were older, had a lower level of education, and had at least one comorbid condition had the lowest QOL.…”

Evaluation of quality of life in individuals with severe chronic motor disability: A major challenge

“…Although, recent studies reported data providing strong arguments to support the conclusion that patients with cognitive dysfunction are reliable and consistent when answering a QoL questionnaire. These works suggested that cognitive dysfunction did not compromise the reliability or validity of the selfreported QoL questionnaires among subjects with cognitive dysfunction and clarify the relevance of using self-reported QoL assessments in clinical practice (12,65,66).…”