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Dementia diagnostics in primary care: with a focus on cognitive testing
Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background

Age is the greatest risk factor for developing dementia and the total number of people aged 60 years and above is expected to more than double globally from 2013 to 2050 (1). Primary health care (PHC) is important for basic diagnostic evaluations. Objective test measurements have been shown to be more reliable than a patient's subjective memory complaints in dementia assessments (2). However, several studies indicate the low use of objective cognitive screening tools in dementia diagnostics in PHC (3). Some general practitioners (GPs) do not perceive today’s cognitive instruments as helpful in the diagnostic process and administration problems have been reported in PHC (4, 5).

The overall aim of this thesis was to investigate the accuracy of several cognitive tests used in dementia assessments in PHC, especially among older patients: A Quick Test of Cognitive Speed (AQT), Cognistat and Cognitive Assessment Battery (CAB). The normative values of the Mini Mental Status Examination (MMSE) in the oldest old was also studied.

Methods

The studies included in this thesis are from two different study populations.

  • Studies I, II and IV. Patients with and without cognitive symptoms were recruited from four primary health care centres in Sweden between 2007 and 2009.
  • Study III. The Elderly in Linköping Screening Assessment (ELSA 85) cohort-population examined people born in 1922 in the municipality of Linköping, Sweden.

Results

Study I. Results showed that AQT is a usable test for dementia diagnosis in PHC. Sensitivity for AQT is superior to the Clock Drawing Test (CDT), equivalent to MMSE and the combination MMSE and CDT. The AUC for AQT was 0.773, valued good enough.

Study II. Overall, the results for Cognistat in this study are superior to MMSE and CDT, also in combination. Cognistat is promising for improved dementia diagnosis in PHC with a quick and easily administered multi-domain test for dementia assessments.

Study III. This study presents valuable information about normative MMSE data for the oldest patients. Results, suggest using the 25th percentile in MMSE of 25 to 26 points, and indicate that MMSE 26 is as a reasonable cut-off for cognitive decline and further medical evaluation in older persons aged from 85 to 93 years.

Study IV. In summary, the additive value of the CAB test in dementia investigations in PHC is not obvious. In addition to questionable accuracy, the test is quite time consuming and normative values are scarce. By introducing the numerical sum (CABsum) the accuracy was increased.

Conclusion

In conclusion, objective cognitive tests are an important part of dementia diagnosis in PHC and there is a need for improved instruments and norm-values. From our results, several cognitive quick tests are usable in PHC - MMSE, AQT and Cognistat - but they have some disadvantages. MMSE 26 is a reasonable cut-off for cognitive decline in the oldest patients 85 to 93 years from a well-educated population with quite good socioeconomic. There is a great interest in finding short and better multi-domain instruments but the additive value of CAB in dementia investigations in PHC is questionable.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. , p. 80
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1691
National Category
General Practice
Identifiers
URN: urn:nbn:se:liu:diva-160371DOI: 10.3384/diss.diva-160371ISBN: 9789176850374 (print)OAI: oai:DiVA.org:liu-160371DiVA, id: diva2:1353042
Public defence
2019-10-18, Berzeliussalen, Hus 463, Campus US, Linköping, 09:00 (Swedish)
Opponent
Supervisors
Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2019-10-01Bibliographically approved
List of papers
1. A Quick Test of Cognitive Speed (AQT): Usefulness in dementia evaluations in primary care
Open this publication in new window or tab >>A Quick Test of Cognitive Speed (AQT): Usefulness in dementia evaluations in primary care
2013 (English)In: Scandinavian Journal of Primary Health Care, ISSN 0281-3432, E-ISSN 1502-7724, Vol. 31, no 1, p. 13-19Article in journal (Refereed) Published
Abstract [en]

Objective. To validate A Quick Test of Cognitive Speed (AQT) as an instrument in diagnostic dementia evaluations against final clinical diagnosis and compare AQT with the Mini-Mental State Examination (MMSE) and Clock Drawing Test (CDT) in primary care. Design. Primary health care cohort survey. Setting. Four primary health care centres and a geriatric memory clinic in Sweden. Patients. 81 patients (age 65 and above) were included: 52 with cognitive symptoms and 29 presumed cognitively healthy. None of the patients had a previous documented dementia diagnosis. All patients performed MMSE, CDT, and AQT at the primary health care clinic and were referred for extensive neuropsychological testing at a memory clinic. AQT was validated against final clinical diagnosis determined by a geriatric specialist and a neuropsychologist. Main outcome measures. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, correlation data, and receiver operating characteristic (ROC). Results. For MMSE, sensitivity and specificity was 0.587 and 0.909; CDT 0.261 and 0.879; and AQT 0.783 and 0.667, respectively. For the combination of MMSE and CDT, sensitivity and specificity was 0.696 and 0.788, for MMSE and AQT 0.913 and 0.636. The ROC curve for AQT showed an area under curve (AUC) of 0.773. Conclusion. Our results suggest AQT is a usable test for dementia assessments in primary care. Sensitivity for AQT is superior to CDT, equivalent to MMSE, and comparable to the combination MMSE and CDT. MMSE in combination with AQT improves sensitivity. Because AQT is user-friendly and quickly administered, it could be applicable for primary care settings.

Place, publisher, year, edition, pages
Informa Healthcare, 2013
Keywords
Alzheimers disease, dementia, general practice, A Quick Test of Cognitive Speed (AQT), Clock Drawing Test (CDT), Mini-Mental Status Examination (MMSE), primary care, Sweden
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-89797 (URN)10.3109/02813432.2012.751699 (DOI)000314653700005 ()
Note

Funding Agencies|Swedish Brain Power||ALF Grants||County Council of Ostergotland||

Available from: 2013-03-07 Created: 2013-03-07 Last updated: 2019-09-20
2. Clinical Utility of Cognistat in Multiprofessional Team Evalutations of Patients with Cognitive Impairment in Swedish Primary Care
Open this publication in new window or tab >>Clinical Utility of Cognistat in Multiprofessional Team Evalutations of Patients with Cognitive Impairment in Swedish Primary Care
2014 (English)In: International Journal of Family Medicine, ISSN 2090-2042, E-ISSN 2090-2050, Vol. 2014, p. 649253-Article in journal (Refereed) Published
Abstract [en]

Background. Diagnostic evaluations of dementia are often performed in primary health care (PHC). Cognitive evaluation requires validated instruments.

Objective. To investigate the diagnostic accuracy and clinical utility of Cognistat in a primary care population.

Methods. Participants were recruited from 4 PHC centres; 52 had cognitive symptoms and 29 were presumed cognitively healthy. Participants were tested using the Mini-Mental State Examination (MMSE), the Clock Drawing Test (CDT), and Cognistat. Clinical diagnoses, based on independent neuropsychological examination and a medical consensus discussion in secondary care, were used as criteria for diagnostic accuracy analyses.

Results. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.85, 0.79, 0.85, and 0.79, respectively, for Cognistat; 0.59, 0.91, 0.90, and 0.61 for MMSE; 0.26, 0.88, 0.75, and 0.46 for CDT; 0.70, 0.79, 0.82, and 0.65 for MMSE and CDT combined. The area under the receiver operating characteristic curve was 0.82 for Cognistat, 0.75 for MMSE, 0.57 for CDT, and 0.74 for MMSE and CDT combined.

Conclusions. The diagnostic accuracy and clinical utility of Cognistat was better than the other tests alone or combined. Cognistat is well adapted for cognitive evaluations in PHC and can help the general practitioner to decide which patients should be referred to secondary care.

 

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2014
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-107048 (URN)10.1155/2014/649253 (DOI)
Available from: 2014-06-04 Created: 2014-06-04 Last updated: 2019-09-20Bibliographically approved
3. Age-Normative MMSE Data for Older Persons Aged 85 to 93 in a Longitudinal Swedish Cohort
Open this publication in new window or tab >>Age-Normative MMSE Data for Older Persons Aged 85 to 93 in a Longitudinal Swedish Cohort
2019 (English)In: Journal of The American Geriatrics Society, ISSN 0002-8614, E-ISSN 1532-5415, Vol. 67, no 3, p. 534-538Article in journal (Refereed) Published
Abstract [en]

BACKGROUND/OBJECTIVES: Normative Mini-mental state examination (MMSE) reference values in elderly are scarce. Therefore, the aim is to present normative MMSE values for 85-93 year olds.

DESIGN: A longitudinal age cohort study.

SETTING: A population study of the residents in the municipality of Linköping, Sweden.

PARTICIPANTS: Residents (n = 650) born in 1922 during the course of 2007. In total, 374 individuals participated and were tested with MMSE at age 85, 280 of these were willing and able to also participate at age 86, 107 at age 90 and 51 at age 93.

MEASUREMENTS: MMSE, from 0-30, with lower scores denoting more impaired cognition.

RESULTS: Median MMSE values for the total population over the ages 85, 86, 90 and 93 years was 28 for all ages investigated. The 25th percentile values were 26, 26, 26 and 27, respectively. For a "brain healthy" sub-group median values were 28, 29, 28, and 28. The 25th percentile values were 27, 28, 26 and 27, respectively. Comparisons for age-effects showed no differences when all individuals for each age group were compared. When only the individuals reaching 93 years of age (n = 50) were analyzed, there was a significant lowering of MMSE in that age group.

CONCLUSION: The literature is variable and in clinical practice a low (24) MMSE cut off is often used for possible cognitive impairment in old age. The present data indicate that MMSE 26 is a reasonable cut off for possible cognitive decline in older persons up to the age of 93. J Am Geriatr Soc 67:534-538, 2019.

Place, publisher, year, edition, pages
Wiley-Blackwell Publishing Inc., 2019
Keywords
aged 80 and over, dementia test, mental status
National Category
Geriatrics
Identifiers
urn:nbn:se:liu:diva-160367 (URN)10.1111/jgs.15694 (DOI)000461567700019 ()30536796 (PubMedID)2-s2.0-85058337422 (Scopus ID)
Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2020-04-29Bibliographically approved
4. Accuracy of the Cognitive Assessment Battery in a Primary Care Population
Open this publication in new window or tab >>Accuracy of the Cognitive Assessment Battery in a Primary Care Population
2019 (English)In: Dementia and Geriatric Cognitive Disorders Extra, E-ISSN 1664-5464, Vol. 9, no 2, p. 294-301Article in journal (Refereed) Published
Abstract [en]

Background: There are several cognitive assessment tools used in primary care, e.g., the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment. The Cognitive Assessment Battery (CAB) was introduced as a sensitive tool to detect cognitive decline in primary care. However, primary care validation is lacking. Therefore, we investigated the accuracy of the CAB in a primary care population. 

Objective: To investigate the accuracy of the CAB in a primary care population. 

Methods: Data from 46 individuals with cognitive impairment and 33 individuals who visited the primary care with somatic noncognitive symptoms were analyzed. They were investigated with the MMSE, the CAB, and a battery of neuropsychological tests; they also underwent consultation with a geriatric specialist. The accuracy of the CAB was assessed using c-statistics and the area under the receiver operating characteristic curve (AUC) was used to quantify the binary outcomes (“no cognitive impairment” or “cognitive impairment”).

Results: The “cognitive impairment” group was significantly different from the unimpaired group for all the subtests of the CAB. When accuracy was based on binary significant reduction or not in one or several domains of the CAB, the AUC varied between 0.685 and 0.772. However, when a summation or logistic regression of several subcategories was performed, using the numerical values for each subcategory, the AUC was >0.9. For comparison, the AUC for the MMSE was 0.849.

Conclusions: The accuracy of the CAB in a primary care population is poor to good when using binary cutoffs. Accuracy can be improved to high when using a summation or logistic regression of the numerical data of the subcategories. Considering CAB time, lack of adequate age norms, and a good accuracy for the MMSE, implementation of the CAB in primary care is not recommended at present based on the results of this study.

Place, publisher, year, edition, pages
S. Karger, 2019
Keywords
Primary care cognitive tests, Cognitive Assessment Battery, Cognitive assessment tools
National Category
Neurology Geriatrics
Identifiers
urn:nbn:se:liu:diva-160370 (URN)10.1159/000501365 (DOI)000496485700009 ()2-s2.0-85071030454 (Scopus ID)
Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2023-03-20Bibliographically approved

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