Introduction

Jim Galvin and colleagues at Washington University, St. Louis, Missouri, have developed a simple tool to discern very early dementia in routine clinical settings. The field overwhelmingly agrees that dementia should be detected as early as possible, yet commonly used tests, such as the MMSE, tend to miss dementia until it is well established. In the rush of daily practice very mild cases often go undiagnosed, and when a person finally gets a diagnosis of possible AD, the spouse or adult child says that they began noticing changes years earlier. A key problem is that routine tests compare a person’s performance to group norms. Galvin and colleagues believe it’s better to gauge incipient dementia through loss of the person’s own prior abilities, not by comparing them to a norm.
 

This month, Galvin and colleagues reported results of further evaluation of the AD8 interview in back-to-back papers in Archives of Neurology. One new paper notes that combining the AD8 interview with brief psychometric tests boosts its ability to discern a cognitive impairment in people who do not meet formal clinical criteria for dementia, and the combined procedure is still short enough to be administered in everyday clinical practice. The other paper reports that when there is no informant available, the patient him- or herself can take the AD8, especially when the dementia is still very mild and the patient has insight into their condition.

Jim Galvin led this Webinar on 30 May 2007. Readers are invited to submit additional comments by using our Comments form at the bottom of the page.

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Galvin JE, Roe CM, Coats MA, Morris JC. Patient’s Rating of Cognitive Ability: Using the AD8, a Brief Informant Interview, as a Self-rating Tool to Detect Dementia. Arch Neurol. 2007;64:725-730. View PDF

Galvin JE, Roe CM, Morris JC. Evaluation of Cognitive Impairment in Older Adults: Combining Brief Informant and Performance Measures. Arch Neurol. 2007;64:718-724. View PDF

AD8 Dementia Screening Interview, Guidelines

Background

Background Text
By James Galvin

The diagnosis of Alzheimer disease (AD) and related dementias remains a clinical one, based on intra-individual decline in cognition with interference in accustomed daily activities. Typically, we think of memory impairments as the earliest signs of AD; however, formal neuropsychological assessments are time-consuming, costly, and not readily available in all clinical situations. Consequently, early-stage Alzheimer disease is often missed in community health settings. We therefore began efforts to develop a sensitive and specific cognitive screening tool that is valid, easy to administer, and minimally time-consuming (Galvin et al., 2005). Brief cognitive tests such as the Mini Mental State Examination (MMSE) may help differentiate cognitively normal older adults from those with moderate dementia. While these brief objective measures are easily applicable in clinical practice, the MMSE and other brief tests lack the sensitivity and specificity to detect very mild impairment and may not be culturally sensitive. Brief cognitive tests also may be limited in their ability to detect change because baseline testing is often unavailable. Lastly, it is unclear how helpful many of these brief measures would be in detecting mild cognitive impairment (MCI) or non-amnestic forms of dementia. We have found informant-based assessments of intra-individual change such as the Clinical Dementia Rating (CDR) to be more sensitive than brief performance-based measures that rely on inter-individual norms to detect cognitive change. However, the time-consuming nature of informant interviews precludes their use in many clinical settings. We therefore used this premise to develop a much briefer informant interview, the AD8, which distinguishes individuals with very mild dementia from those without dementia.

The AD8 is an informant-based measure that validly and reliably differentiates non-demented from demented individuals. It is sensitive to the earliest signs of cognitive change as reported by an informant. The AD8 is highly correlated with our gold standard, the CDR and its sum of boxes, as well as performance on objective measures of memory, visuospatial skills, attention, and executive function. The AD8 took the clinical staff less than 3 minutes to complete, and it can be reliably administered either in person or over the phone. The reliability and validity of a brief informant interview such as the AD8 suggests that dementia may be detected at the earliest stages by placing emphasis on intra-individual, rather than inter-individual comparisons. A key concern is that deviation from the patient’s baseline and accustomed activities often is not readily assessed by comparison to a scale determined on the basis of group norms.

We also found that combining the AD8 with brief psychometric tests further improved the ability to screen for the presence of dementia. The addition of the 10-item word list recall improved discrimination to 97 percent between non-demented adults and those with dementia. Using cut-offs of two or greater on the AD8 and five or fewer words on the word list recall resulted in excellent sensitivity (94 percent) and specificity (82 percent).

In general practice, a reliable informant may not always be available. We wished, therefore, to test whether there is value in asking individuals to self-rate their cognitive abilities. Self-rating scales for dementia have not gained common use because of the perception that dementia patients lack insight and deny cognitive problems, even in mild forms of dementia. The AD8, although developed as an informant rating, may also serve as a self-rating tool to discriminate older adults without dementia from those with even the mildest forms of dementia. The self-rated AD8 corresponded to gold standards for this study (the CDR and CDR-SB) and to brief global assessments of cognition (MMSE and SBT) and had adequate agreement with the informant’s AD8 rating. The participants were able to complete the AD8 within 3 minutes without additional instructions.

Subjective cognitive complaints are common in older adults, found in up to 88 percent of people over age 85. These complaints are often attributed to depression. A short scale addressing self-rating of cognitive abilities may be preferable to asking a single question about memory self-perception to assess memory complaints (i.e., “Are you having a problem with your memory?”).

In summary, the AD8 is a brief screening tool that may discriminate healthy older adults from those with very mild dementia. The AD8 is administered preferably to an informant. In the absence of an informant, the AD8 can be administered to the patient. If the patient endorses any of its questions, further evaluation is warranted. The AD8 may be applicable as a screening tool in community settings and primary care to assist in the detection of dementia in the older adult.

We suggest these questions for discussion:

1. What patients do you evaluate for cognitive disorders?

2. What screening tools do you currently use for detecting dementia?

3. Are you satisfied with the currently available tools for diagnosing dementia?

4. What are the potential barriers to screening patients for dementia?

5. How does the AD8 compare to the MMSE?

6. What will it take for the field to adopt the AD8?

References:
Galvin JE, Roe CM, Powlishta KK, Coats MA, Muich SJ, Grant E, Miller JP, Storandt M, Morris JC. The AD8: A brief informant interview to detect dementia. Neurology. 2005;65:559–564. View PDF

Galvin JE, Roe CM, Xiong C, Morris JC. Validity and reliability of the AD8 informant interview in dementia. Neurology. 2006;67:1942–1948. View PDF

Galvin JE, Roe CM, Coats MA, Morris JC. Patient’s Rating of Cognitive Ability: Using the AD8, a Brief Informant Interview, as a Self-rating Tool to Detect Dementia. Arch Neurol. 2007;64:725-730. View PDF

Galvin JE, Roe CM, Morris JC. Evaluation of Cognitive Impairment in Older Adults: Combining Brief Informant and Performance Measures. Arch Neurol. 2007;64:718-724. View PDF

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References

Webinar Citations

1. The AD8: A Brief Screening Tool for Very Mild Dementia 25 May 2007

Paper Citations

1. Galvin JE, Roe CM, Powlishta KK, Coats MA, Muich SJ, Grant E, Miller JP, Storandt M, Morris JC. The AD8: a brief informant interview to detect dementia. Neurology. 2005 Aug 23;65(4):559-64. PubMed.

Other Citations

1. View PDF

External Citations

1. cognitive screening tool
2. AD8 Dementia Screening Interview, Guidelines

Further Reading