Development and Validation the Mobile Toolbox (MTB) Spelling Test

Background

Spelling assessments can provide a valuable marker of cognitive change in Alzheimer’s disease and related dementias (ADRD) and play an important role in ADRD research. However, most commercial assessments are not well-suited to the needs of researchers or participants; they are expensive and often require face-to-face administration by a trained examiner. To help overcome these barriers and foster progress in ADRD research, the National Institute on Aging (NIA)-funded Mobile Toolbox (MTB) offers a library of cognitive measures that can be self-administered remotely on a participant’s own smartphone, including a brand-new Spelling test.

Objective

The goal of this paper is to describe the design, piloting, calibration, and validation of the MTB Spelling test.

Design

We describe a pilot study, calibration study, and three validation studies, all of which use a cross-sectional design.

Setting

The pilot study, calibration study, and validation studies 2 and 3 were conducted remotely, while validation study 1 was conducted in the lab.

Participants

Participants for all of the studies were recruited from the general population by a thirdparty market research firm and the samples were stratified by age, gender, race, ethnicity, and education to represent the U.S. population. The pilot sample included 1,950 participants and the calibration study included 1335 participants over the age of 8. Validation study 1 included 92 participants ages 20 to 84, validation study 2 included 1021 participants ages 18 to 90, and validation study 3 included 168 participants ages 28 to 87.

Measurements

Participants in each of the studies completed the MTB Spelling test. Participants in validation studies 1 and 2 completed measures from the NIH Toolbox including Oral Reading Recognition as a measure of convergent validity, and Visual Reasoning and the Rey Auditory Verbal Learning as measures of divergent validity. As an additional measure of convergent validity, participants in study 1 also completed the Spelling subtest from the Wechsler Individual Achievement Test, 4th Edition.

Results

The MTB Spelling test demonstrated evidence of internal consistency (r=.79 to.83) convergent validity (r=.56 to.81, p<.01), discriminant validity (r =.23 to.36, p <.01), test-retest reliability (ICC=.63), and correlations with normal cognitive aging (r = −.06 to −.04, p >.01).

Conclusion

Findings suggest the MTB Spelling test is a reliable and valid measure of English spelling abilities in general population samples, and has potential in ADRD research.