Objective: To develop and validate a new standardized confusion assessment method (CAM) that enables nonpsychiatric clinicians to detect delirium quickly in high-risk settings.

Design: Prospective validation study.

Setting: Conducted in general medicine wards and in an outpatient geriatric assessment center at Yale University (site 1) and in general medicine wards at the University of Chicago (site 2).

Patients: The study included 56 subjects, ranging in age from 65 to 98 years. At site 1, 10 patients with and 20 without delirium participated; at site 2, 16 patients with and 10 without delirium participated.

Measurements and Main Results: An expert panel developed the CAM through a consensus building process. The CAM instrument, which can be completed in less than 5 minutes, consists of nine operationalized criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R). An a priori hypothesis was established for the diagnostic value of four criteria: acute onset and fluctuating course, inattention, disorganized thinking, and altered level of consciousness. The CAM algorithm for diagnosis of delirium required the presence of both the first and the second criteria and of either the third or the fourth criterion. At both sites, the diagnoses made by the CAM were concurrently validated against the diagnoses made by psychiatrists. At sites 1 and 2 values for sensitivity were 100% and 94%, respectively; values for specificity were 95% and 90%; values for positive predictive accuracy were 91% and 94%; and values for negative predictive accuracy were 100% and 90%. The CAM algorithm had the highest predictive accuracy for all possible combinations of the nine features of delirium. The CAM was shown to have convergent agreement with four other mental status tests, including the Mini-Mental State Examination. The interobserver reliability of the CAM was high (kappa = 0.81 - 1.0).

Conclusions: The CAM is sensitive, specific, reliable, and easy to use for identification of delirium.

References

  • 1. LevkoffBesdineWetle SRT. Acute confusional states (delirium) in the hospitalized elderly. Ann Rev Gerontol Geriatr. 1986;6:1-26. MedlineGoogle Scholar
  • 2. Hodkinson H. Mental impairment in the elderly. J R Coll Physicians Lond. 1973;7:305-17. MedlineGoogle Scholar
  • 3. Report of the Royal College of Physicians by the College Committee on Geriatrics. Organic mental impairment in the elderly. J R Coll Physicians Lond. 1981;15:141-67. MedlineGoogle Scholar
  • 4. ChisholmDenistonIngrisanBarbus SORA. Prevalence of confusion in elderly hospitalized patients. Journal of Gerontological Nursing. 1982;8:87-96. CrossrefMedlineGoogle Scholar
  • 5. GillickSerrellGillick MNL. Adverse consequences of hospitalization in the elderly. Soc Sci Med. 1982;16:1033-8. CrossrefMedlineGoogle Scholar
  • 6. WarshawMooreFriedman GJS. Functional disability in the hospitalized elderly. JAMA. 1982;248:847-50. CrossrefMedlineGoogle Scholar
  • 7. Cavanaugh S. The prevalence of emotional and cognitive dysfunction in a general medical population: using the MMSE, GHQ, and BDI. Gen Hosp Psychiatry. 1983;5:15-24. CrossrefMedlineGoogle Scholar
  • 8. Lipowski Z. Transient cognitive disorders (delirium, acute confusional states) in the elderly. Am J Psychiatry. 1983;140:1429-36. Google Scholar
  • 9. WilliamsCampbellRaynorMusholtMlynarczykCrane MEWMSL. Predictors of acute confusional states in hospitalized elderly patients. Res Nurs Health. 1985;8:31-40. CrossrefMedlineGoogle Scholar
  • 10. Foreman M. Confusion in the hospitalized elderly: incidence, on-set, and associated factors. Res Nurs Health. 1989;12:21-9. CrossrefMedlineGoogle Scholar
  • 11. Lipowski Z. Acute confusional states (delirium) in the elderly. In: Albert ML, ed. Clinical Neurology of Aging. New York: Oxford University Press; 1984:279-97. Google Scholar
  • 12. Bedford P. General medical aspects of confusional states in elderly people. Br Med J [Clin Res]. 1959;2:185-8. CrossrefMedlineGoogle Scholar
  • 13. Lipowski Z. Delirium (acute confusional states). JAMA. 1987;258:1789-92. CrossrefMedlineGoogle Scholar
  • 14. WilliamsWardCampbell MSE. Issues in studying confusion in older hospitalized patients [Abstract]. In: Stinson SM, Kerr JC, Giovanetti P, Field PA, MacPhail J, eds. New Frontiers in Nursing Research. Edmonton: University of Alberta Press; 1986:390. Google Scholar
  • 15. Wedding W. The mortality of delirium: an underappreciated problem. Psychosomatics. 1982;23:1232-5. CrossrefMedlineGoogle Scholar
  • 16. LamontSampsonMatthiasKane CSRR. The outcome of hospitalization for acute illness in the elderly. J Am Geriatr Soc. 1983;31:282-8. CrossrefMedlineGoogle Scholar
  • 17. ZaritZarit SJ. Cognitive impairment. In: Lewinsohn PM, Teri L, eds. Clinical Geropsychiatry: New Directions in Assessment and Treatment. New York: Pergamon Press; 1983:38-80. Google Scholar
  • 18. FrancisStrongMartinKapoor JSDW. Delirium in elderly general medical patients: common but often unrecognized [Abstract]. Clin Res. 1988;36:711A. Google Scholar
  • 19. WilliamsHollowayWinn MJM. Nursing activities and acute confusional states in elderly hip-fractured patients. Nurs Res. 1979;28:25-35. CrossrefMedlineGoogle Scholar
  • 20. FolsteinFolsteinMcHugh MSP. The Folstein Mini-Mental State Examination: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12:189-98. CrossrefMedlineGoogle Scholar
  • 21. LowyEngelsmanLiposwki FFZ. Study of cognitive functioning in a medical population. Compr Psychiatry. 1973;14:331-8. CrossrefMedlineGoogle Scholar
  • 22. GustafsonBerggrenBrannstrom YDB. Acute confusional states in elderly patients treated for femoral neck fracture. J Am Geriatr Soc. 1988;36:525-30. CrossrefMedlineGoogle Scholar
  • 23. BerggrenGustafsonEriksson DYB. Postoperative confusion after anesthesia in elderly patients with femoral neck fractures. Anesth Analg. 1987;66:497-504. CrossrefMedlineGoogle Scholar
  • 24. CameronThomasMulvihillBronheim DRMH. Delirium: a test of the Diagnostic and Statistical Manual III criteria on medical inpatients. J Am Geriatr Soc. 1987;35:1007-10. CrossrefMedlineGoogle Scholar
  • 25. JacobsBernhardDelgadoStrain JMAJ. Screening for organic mental syndromes in the medically ill. Ann Intern Med. 1977;86:40-6. LinkGoogle Scholar
  • 26. KatzAgleDePalmaDeCosse NDRJ. Delirium in surgical patients under intensive care: utility of mental status examination. Arch Surg. 1972;104:310-3. CrossrefMedlineGoogle Scholar
  • 27. KiernanMuellerLangstonVan Dyke RJJC. The neurobehavioral cognitive status examination: a brief but differentiated approach to cognitive assessment. Ann Intern Med. 1987;107:481-5. LinkGoogle Scholar
  • 28. ScwammVan DykeKiernanMerrinMueller LCREJ. The neurobehavioral cognitive status examination: comparison with the Cognitive Capacity Screening Examination and the Mini-Mental State Examination in a neurosurgical population. Ann Intern Med. 1987;107:486-91. LinkGoogle Scholar
  • 29. TrzepaczBakerGreenhouse PWJ. A symptom rating scale for delirium. Psychiatry Res. 1988;23:89-97. CrossrefMedlineGoogle Scholar
  • 30. AnthonyLeRescheVonKorffNiazFolstein JLMUM. Screening for delirium on a general medical ward: the tachistoscope and a global accessibility rating. Gen Hosp Psychiatry. 1985;7:36-42. CrossrefMedlineGoogle Scholar
  • 31. . Diagnostic and Statistical Manual of Mental Disorders. 3d ed. Washington, DC: American Psychiatric Association; 1987:97-124. Google Scholar
  • 32. Foreman M. Acute confusional states in the hospitalized elderly: a research dilemma. Nurs Res. 1986;35:34-8. CrossrefMedlineGoogle Scholar
  • 33. . Diagnostic and Statistical Manual of Mental Disorders. 3d ed. Washington, DC: American Psychiatric Association; 1980:104-7. Google Scholar
  • 34. Cavalieri T. Acute confusional states in the geriatric population. J Am Osteopath Assoc. 1984;83:801-5. MedlineGoogle Scholar
  • 35. Foreman M. Acute confusional states in the elderly: an algorithm. Dimensions of Critical Care Nursing. 1984;3:207-15. CrossrefMedlineGoogle Scholar
  • 36. Hodkinson H. Mental impairment in the elderly. J R Coll Physicians Lond. 1973;7:305-17. MedlineGoogle Scholar
  • 37. Doty E. The incidence and treatment of delirious reactions in later life. Geriatrics. 1946;1:21-6. MedlineGoogle Scholar
  • 38. Jolley D. Acute confusional states in the elderly. In: Coakley D, ed. Acute Geriatric Medicine. London: Croom Helm; 1981:175-89. Google Scholar
  • 39. PurdieHonigmanRosen FBP. Acute organic brain syndrome: a review of 100 cases. Ann Emerg Med. 1981;10:455-61. CrossrefMedlineGoogle Scholar
  • 40. MorseLitin RE. The anatomy of a delirium. Am J Psychiatry. 1971;128:143-8. CrossrefGoogle Scholar
  • 41. FlintRichards FS. Organic basis of confusional states in the elderly. Br Med J [Clin Res]. 1956;2:1537-9. CrossrefMedlineGoogle Scholar
  • 42. WilliamsCampbellRaynorMlynarczykWard MEWSS. Reducing acute confusional states in elderly patients with hip fractures. Res Nurs Health. 1985;8:329-37. CrossrefMedlineGoogle Scholar
  • 43. SeymourHenschkeCapeCampbell DPRA. Acute confusional state and dementia in the elderly: the role of dehydration/volume depletion, physical illness and age. Age Ageing. 1980;9:137-46. CrossrefMedlineGoogle Scholar
  • 44. McKhann G. Disorders of consciousness. In: Harvey AM, ed. The Principles and Practice of Medicine. 20th ed. New York: Appleton-Century-Crofts: 1980:1188-90. Google Scholar
  • 45. RabinsFolstein PM. Delirium and dementia: diagnostic criteria and fatality rates. Br J Psychiatry. 1982;140:149-53. CrossrefMedlineGoogle Scholar
  • 46. TrzepaczTeagueLipowski PGZ. Delirium and other organic mental disorders in a general hospital. Gen Hosp Psychiatry. 1985;7:101-6. CrossrefMedlineGoogle Scholar
  • 47. ChedruGeschwind FN. Disorders of higher cortical functions in acute confusional states. Cortex. 1972;8:395-411. CrossrefMedlineGoogle Scholar
  • 48. Feinstein A. Clinimetrics. New Haven: Yale University Press; 1987:194-5, 208. Google Scholar
  • 49. ScherrAlbertFunkenstein PMH. Correlates of cognitive function in an elderly community population. Am J Epidemiol. 1988;128:1084-101. CrossrefMedlineGoogle Scholar
  • 50. StrubBlack RF. The Mental Status Examination in Neurology. Philadelphia: F.A. Davis Company; 1977:18-9. Google Scholar
  • 51. Cummings J. Clinical Neuropsychiatry. Orlando: Grune and Stratton, Inc.; 1985:9. Google Scholar
  • 52. Feinstein A. Clinical Epidemiology: The Architecture of Clinical Research. Philadelphia: W.B. Saunders Company; 1985:145-52, 186. Google Scholar
  • 53. InouyeHorwitzTinettiBerkman SRML. Acute confusional states in the hospitalized elderly: incidence, risk factors, and complications [Abstract]. Clin Res. 1989;37:524A. Google Scholar

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