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Research Christmas 2009: Young and old

Lying obliquely—a clinical sign of cognitive impairment: cross sectional observational study

BMJ 2009; 339 doi: (Published 16 December 2009) Cite this as: BMJ 2009;339:b5273
  1. Peter Kraft, resident physician1,
  2. Ottar Gadeholt, resident physician1,
  3. Matthias J Wieser, psychologist2,
  4. Jenifer Jennings, Fulbright program exchange student1,
  5. Joseph Classen, professor of neurology13
  1. 1Department of Neurology, University of Wuerzburg, Germany
  2. 2Department of Psychology I, University of Wuerzburg, Germany
  3. 3Department of Neurology, University of Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany
  1. Corresponding author: J Classen joseph.classen{at}
  • Accepted 17 November 2009


Objective To determine if failure to spontaneously orient the body along the longitudinal axis of a hospital bed when asked to lie down is associated with cognitive impairment in older patients.

Design Cross sectional observational study.

Setting Neurology department of a university hospital in Germany.

Participants Convenience sample of 110 older (≥60 years) inpatients with neurological conditions and 23 staff neurologists.

Main outcome measures The main outcome measure was the association between the angle of the body axis and the results of three cognitive screening tests (mini-mental state examination, DemTect, and clock drawing test). Staff doctors were shown photographs of a model taken at a natural viewing able to determine their subjective perspective of what constitutes oblique.

Results 110 neurological inpatients (mean age 70.9 (SD 6.8) years) were included after exclusions. Evidence of cognitive impairment was found in 34, with scores indicating dementia in eight, according to the mini-mental state examination, and in 11 according to the DemTect. Across all patients, the mean angular deviation of the body axis from the longitudinal axis of the bed (range 0-23°) correlated linearly with the mini-mental state examination (r=−0.480), DemTect (r=−0.527), and the clock drawing test (r=−0.552) scores (P<0.001 for all), even after removing age as a covariate. Overall, 90% of staff neurologists considered a minimal body angle of 7° to be oblique. Angular deviation of at least 7° predicted cognitive impairment according to the three different tests, with specificities between 89% and 96% and sensitivities between 27% and 50%.

Conclusion Clinicians might suspect cognitive impairment in mobile older inpatients with neurological disorders who spontaneously position themselves obliquely when asked to lie on a bed.


  • We thank Klaus V Toyka (Department of Neurology, University of Wuerzburg) and Reinhard Gentner (Human Cortical Physiology Laboratory, Department of Neurology, University of Wuerzburg) for helpful comments, and staff doctors for participating.

  • Contributors: JC conceived, designed, and supervised the study. OG, JJ, and PK acquired the data. JC, OG, PK, and MJW analysed and interpreted the data. JC, PK, and OG drafted the manuscript. JC, PK, OG, JJ, and MJW critically revised the manuscript for important intellectual content. MJW and JC carried out the statistical analysis. PK and OG contributed equally. All authors had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors have seen and approved the final manuscript.

  • Funding: This study was part of OG’s MD thesis. The study was supported by research funds from the State of Bavaria. The sponsor did not have any active role in the study. The researchers were independent of the funders.

  • Competing interests: None declared.

  • Ethical approval: This study was approved by the ethics committee of the University of Wuerzburg.

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