Deriving reference limits from historical data – A comparison of four novel methods

Clinical Neurophysiology, vol. 182, pp. 2111451

Abstract

OBJECTIVE: To compare four novel methods - extrapolated norms (E-norms), extrapolated reference values (E-Ref), multivariable extrapolated reference values (MeRef) and mixture model clustering (MMC) - for obtaining reference limits for nerve conduction studies (NCS) from historical data containing both normal and abnormal studies. METHODS: Reference limits for 29 commonly clinically used NCS measurements were calculated from a historical database containing measurements from 24618 patients using E-norms, E-ref, MeRef and MMC. The resulting reference limits were compared to reference limits for NCS calculated from 680 healthy subjects using Youden's J statistics. RESULTS: Except for distal latencies, E-norms produced reference limits with the highest Youden's J statistics with higher sensitivity, but lower specificity. E-Ref, MeRef and MMC produced reference limits with high specificity, but lower sensitivity than E-norms. CONCLUSIONS: There are substantial differences in the performance of E-norms, E-Ref, MeRef and MMC. A dynamic approach, where the methods used are changed based on the type of NCS measurement and the amount of historical data available, may yield the highest accuracy. SIGNIFICANCE: When combining the different novel methods, it is possible to create clinically useful reference limits using historical data.

Authors 11

1. Tomasz Szymon Szczepanski corresponding

   Oslo University Hospital · University of Oslo

   Affiliation as printed

   Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway. Electronic address: tomszc@ous-hf.no

2. Petter Moe Omland

   Norwegian University of Science and Technology · St Olav's University Hospital

   Affiliation as printed

   Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim, Norway; Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway; NorHEAD - Norwegian Centre for Headache Research , NTNU, Trondheim, Norway

3. Øystein Dunker

   Oslo University Hospital · University of Oslo

   Affiliation as printed

   Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Research and Innovation, Division of Neuroscience, Oslo University Hospital, Oslo, Norway

4. Trond Sand

   Norwegian University of Science and Technology · St Olav's University Hospital

   Affiliation as printed

   Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim, Norway

5. Martijn Rudolf Tannemaat Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leiden University Medical Center, Netherlands

6. Robert H. A. M. Reijntjes Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leiden University Medical Center, Netherlands

7. Anis Yazidi

   OsloMet – Oslo Metropolitan University

   Affiliation as printed

   OsloMet, Oslo, Norway

8. Kerstin Bach

   Norwegian University of Science and Technology

   Affiliation as printed

   Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway

9. John‐Anker Zwart

   Oslo University Hospital · University of Oslo

   Affiliation as printed

   Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Research and Innovation, Division of Neuroscience, Oslo University Hospital, Oslo, Norway

10. Joe F. Jabre

    Tufts University

    Affiliation as printed

    Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA, USA

11. Kristian Bernhard Nilsen

    Oslo University Hospital

    Affiliation as printed

    Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Oslo, Norway