Design and implementation of the mobility assessment tool: software description.

BACKGROUND: In previous work, we described the development of an 81-item video-animated tool for assessing mobility. In response to criticism levied during a pilot study of this tool, we sought to develop a new version built upon a flexible framework for designing and administering the instrument. RESULTS: Rather than constructing a self-contained software application with a hard-coded instrument, we designed an XML schema capable of describing a variety of psychometric instruments. The new version of our video-animated assessment tool was then defined fully within the context of a compliant XML document. Two software applications--one built in Java, the other in Objective-C for the Apple iPad--were then built that could present the instrument described in the XML document and collect participants' responses. Separating the instrument's definition from the software application implementing it allowed for rapid iteration and easy, reliable definition of variations. CONCLUSIONS: Defining instruments in a software-independent XML document simplifies the process of defining instruments and variations and allows a single instrument to be deployed on as many platforms as there are software applications capable of interpreting the instrument, thereby broadening the potential target audience for the instrument. Continued work will be done to further specify and refine this type of instrument specification with a focus on spurring adoption by researchers in gerontology and geriatric medicine.

The Virtual Short Physical Performance Battery.

BACKGROUND: Performance-based and self-report instruments of physical function are frequently used and provide complementary information. Identifying older adults with a mismatch between actual and perceived function has utility in clinical settings and in the design of interventions. Using novel, video-animated technology, the objective of this study was to develop a self-report measure that parallels the domains of objective physical function assessed by the Short Physical Performance Battery (SPPB)-the virtual SPPB (vSPPB). METHODS: The SPPB, vSPPB, the self-report Pepper Assessment Tool for Disability, the Mobility Assessment Tool-short form, and a 400-m walk test were administered to 110 older adults (mean age = 80.6±5.2 years). One-week test-retest reliability of the vSPPB was examined in 30 participants. RESULTS: The total SPPB (mean [±SD] = 7.7±2.8) and vSPPB (7.7±3.2) scores were virtually identical, yet moderately correlated (r = .601, p < .05). The component scores of the SPPB and vSPPB were also moderately correlated (all p values <.01). The vSPPB (intraclass correlation = .963, p < .05) was reliable; however, individuals with the lowest function overestimated their overall lower extremity function while participants of all functional levels overestimated their ability on chair stands, but accurately perceived their usual gait speed. CONCLUSION: In spite of the similarity between the SPPB and vSPPB, the moderate strength of the association between the two suggests that they offer unique perspectives on an older adult's physical function.