We report on the development and initial validation of 13 brief measures of QOL for adults with neurologic disorders. Each Neuro-QOL short form comprises a set of items that have been carefully selected from item banks to enhance estimation of a patient's health status. The length of each short form ranges from 8 to 9 items; each can be completed in less than 2 minutes by the typical patient.19
A profile of 6 selected domains, for example, would require approximately 10 minutes to complete. This compares favorably to other QOL instruments in common use, which can take as many as 20 minutes or more. Scoring look-up tables are available in appendix e-1 on the Neurology®
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. Researchers also may design their own short forms by selecting items from the item banks. In that case, scoring and converting to the T-score metric can be done with direction also provided in appendix e-1. The short forms reported here provide a practical opportunity for multidimensional assessment in neurologic clinical research or practice. Over time and with accumulating publications, their use can be enhanced by increased interpretability with regard to the meaning of specific scores and score changes. For now, the interpretability of these scales surrounds the reference point provided by the T score. Specifically, the following 4 banks were referenced against a clinical neurology population: sleep disturbance, fatigue, emotional and behavioral dyscontrol, and stigma. T scores from the other 9 item banks are referenced against the US general population. Therefore, when interpreting sleep disturbance, fatigue, emotional and behavioral dyscontrol, or stigma scores, one should consider a score of 60, for example, to be 1 SD higher (worse) than the average of the clinical neurology sample described here and elsewhere.11
When interpreting scores on the other 9 item banks or short forms, one should consider the reference group to be the US general population. That same score of 60 would be 1 SD higher (worse) than the average US resident (rather than neurology patient) on anxiety or depression, and 1 SD higher (better) than the average US resident on upper and lower extremity function, applied cognition, positive affect and well-being, ability to participate in social roles and activities, and satisfaction with social roles and activities.
The Neuro-QOL measurement system is intended to be brief, reliable, valid, responsive, and consistent enough across the selected conditions to allow for cross-disease comparison, and yet flexible enough to capture condition-specific HRQOL issues. However, there are limitations in the current work which can be addressed in future research. First, the calibration samples were essentially samples of convenience, with most respondents recruited through Internet panel companies. The impact of this sampling strategy is likely negligible with regard to the integrity of the item statistics (“calibrations”), because what is most important for calibration is obtaining a full range of responses to items administered. When the general population sample did not provide sufficient responses in the most impaired response option (i.e., physical function, applied cognition, and sleep), we supplemented cases from the clinical outpatient sample to obtain stable item parameter statistics. However, the predominant use of an Internet panel sample raises questions about the generalizability of the results and the interpretation of T scores. Further research with populations that are not regular Internet users and those with limited reading ability will be important. In addition, it will be very important to evaluate use of these short forms with patients who have limited functional or expressive ability and with proxies. Finally, although we developed Spanish language equivalent assessments for all of these 13 QOL domains, they have not been formally tested or evaluated.
Standardized QOL evaluations such as Neuro-QOL can inform health care accountability, from patient care to health care policy. It does so by improving assessment of patient-reported outcomes and disease burden in neurologic diseases, increasing measurement consistency across neurologic clinical research, and offering a common metric to express burdens of disease and benefits of treatment. Over time, accumulated experience and published results with Neuro-QOL measures will support their use in a variety of applications, from clinical trial research to broader comparative effectiveness research, cross-sectional and longitudinal observational cohort studies, health care delivery observational and intervention studies, and population-based research.