Development of a computer-administered mobility questionnaire.

PURPOSE

Mobility is an important aspect of physical functioning, but feasible and validated self-report assessment instruments for palliative patients are lacking. This study is a part of the European Palliative Research Network research programme, aiming to develop an internationally endorsed assessment tool for symptoms and functioning in palliative cancer care. The specific aim of the present study is to assess psychometric properties of a mobility item bank, with regards to uni-dimensionality, functional coverage, redundant items and gaps in the scale.

METHODS

A cross-sectional study with 604 responses from palliative cancer and 186 from chronic pain patients (mean age 59 ± 14 years, 55% female) was performed. A tablet computer with a touch- sensitive screen was used for data collection. An item pool of 21 mobility items, ranging from sitting without support to running were presented in random order, each scored on a four-category scale rating the difficulty in performing the activity. Psychometric properties were assessed by exploratory factor analysis, internal consistency and item response theory.

RESULTS

The mobility scale can be regarded as uni-dimensional and has good internal consistency (Cronbach's alpha  =  0.97). Items had a wide functional coverage from low to high functioning. Two items were with poor psychometric properties and two redundant items were removed. There were no obvious gaps in the scale.

CONCLUSIONS

The psychometric properties of the scale are good and the next step is to make a pre-programmed version of the scale to be used in a pan-European study.