Classification of evidence ratings, I-IV, and the definitions for practice recommendations based on classification of evidence (Standard, Guideline, Practice Option, Practice Advisory) are defined at the end of the "Major Recommendations" field.
Diagnostic Criteria
Are the current criteria for the diagnosis of dementia reliable?
- The Diagnostic and Statistical Manual, 3rd edition, revised (DSM-III-R) definition of dementia, which is identical to Diagnostic and Statistical Manual, 4th edition (DSM-IV) definition, is reliable and should be used routinely (Guideline).
Are current diagnostic criteria able to establish a diagnosis for the prevalent dementias (Alzheimer’s disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia, prion diseases)?
- The National Institute of Neurologic, Communicative Disorders and Stroke–Alzheimer’s disease and Related Disorders Association (NINCDS-ADRDA) for the diagnosis of probable Alzheimer's disease or the Diagnostic and Statistical Manual, 3rd edition, revised (DSM-III-R) criteria for dementia of the Alzheimer's type (DAT) should be routinely used (Guideline).
- The Hachinski Ischemic Index criteria may be of use in the diagnosis of cerebrovascular disease in dementia (Option).
- The Consortium for dementia with Lewy bodies (DLB) diagnostic criteria may be of use in clinical practice (Option).
- The Consensus diagnostic criteria for frontotemporal dementia (FTD) may be of use in clinical practice (Option).
- Clinical criteria for Creutzfeldt-Jakob disease (CJD) should be used in rapidly progressive dementia syndromes (Guideline).
Laboratory Tests
Do laboratory tests improve the accuracy of clinical diagnosis of dementing illness?
- Structural neuroimaging with either a noncontrast computed tomography or magnetic resonance scan in the initial evaluation of patients with dementia is appropriate. (Guideline).
- Linear or volumetric magnetic resonance or computed tomography measurement strategies for the diagnosis of Alzheimer's Disease and are not recommended for routine use at this time (Guideline).
- For patients with suspected dementia, single photon emission computed tomography (SPECT) cannot be recommended for routine use in either initial or differential diagnosis as it has not demonstrated superiority to clinical criteria (Guideline).
- Positron emission tomography (PET) imaging is not recommended for routine use in the diagnostic evaluation of dementia at this time (Guideline).
- Genetic testing of patients with suspected dementia with Lewy bodies and Creutzfeldt-Jakob disease is not recommended (Guideline).
- Routine use of apolipoprotein E (APOE) genotyping in patients with suspected Alzheimer's disease is not recommended at this time (Guideline).
- There are no other genetic markers recommended for routine use in the diagnosis of Alzheimer’s disease (Guideline).
- Testing for tau mutations or Alzheimer's disease gene mutations is not recommended for routine evaluation in patients with frontotemporal dementia at this time (Guideline).
- There are no cerebrospinal fluid or other biomarkers recommended for routine use in determining the diagnosis of Alzheimer's disease at this time (Guideline).
- The cerebrospinal fluid 14-3-3 protein is useful recommended for confirming or rejecting the diagnosis of Creutzfeldt–Jakob disease in clinically appropriate circumstances (Guideline).
Screening for Comorbid Diseases
What comorbidities should be screened for in elderly patients undergoing an initial assessment for dementia?
- Depression is a common, treatable comorbidity in patients with dementia and should be screened for (Guideline).
- B12 deficiency is common in the elderly, and B12 levels should be included in routine assessments of the elderly. (Guideline).
- Because of its frequency, hypothyroidism should be screened for in elderly patients. (Guideline).
- Unless the patient has some specific risk factor or evidence of prior syphilitic infection, or resides in one of the few areas in the United States with high numbers of syphilis cases, screening for the disorder in patients with dementia is not justified (Guideline).
Definitions:
Classification of Evidence
- Evidence provided by a well-designed prospective study in broad spectrum of persons with the suspected condition, using a "gold standard" for case definition, in which test is applied in a blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy.
- Evidence provided by a well-designed prospective study of a narrow spectrum of persons with the suspected condition, or a well designed retrospective study of a broad spectrum of persons with an established condition (by "gold standard") compared with a broad spectrum of controls, in which test is applied in blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy.
- Evidence provided by a retrospective study in which either persons with the established condition or controls are of a narrow spectrum, and in which test is applied in a blinded evaluation
- Any design in which test is not applied in blinded evaluation OR evidence provided by expert opinion alone or in descriptive case series (without controls).
Practice Recommendations Based on Classification of Evidence
Standard. Principle for patient management that reflects a high degree of clinical certainty (usually this requires Class I evidence that directly addresses the clinical question, or overwhelming Class II evidence when circumstances preclude randomized clinical trials).
Guideline. Recommendation for patient management that reflects moderate clinical certainty (usually this requires Class II evidence or a strong consensus of Class III evidence).
Practice Option. Strategy for patient management for which the clinical utility is uncertain (inconclusive or conflicting evidence or opinion).
Practice Advisory. Practice recommendation for emerging and/or newly approved therapies or technologies based on evidence from at least one Class I study. The evidence may demonstrate only a modest statistical effect or limited (partial) clinical response, or significant cost–benefit questions may exist. Substantial (or potential) disagreement among practitioners or between payers and practitioners may exist.