The behavior changes associated with early dementia have not been well characterized. Better identification of behavior changes would help physicians decide which patients should be further evaluated for dementia. Ready and colleagues investigated two amnestic behavior changes (repetitive questioning and repetitive actions) to determine whether they are useful in screening for early dementia.
Study participants were patients from a hospital-based memory disorder clinic. Persons who knew the 75 study patients well and accompanied them to the clinic were identified as informants. Informants were asked whether the patient asks the same question over and over (repetitive question item) and repeats the same action over and over (repetitive action item). Medical chart reviews provided patient data and diagnoses. The full sample also included 25 control subjects; the remaining participants had no cognitive disorder, undetermined dementia, or definite dementia. The classification performance of the amnestic behavior items was compared with the Mini-Mental State Examination (MMSE).
Cutoffs were determined to arrive at the best sensitivity and specificity for distinguishing patients with dementia from control subjects. The repetitive question item exhibited a sensitivity of 0.88, a specificity of 0.72, and a classification accuracy of 82 percent. The repetitive action item had a classification accuracy of 66 percent. Combining data from the two behavioral questions resulted in a sensitivity of 0.97, a classification accuracy of 81 percent, and a specificity of 0.61. The more liberal MMSE cutoff score (23) had a specificity of 0.97 and a classification accuracy of 75 percent, but a sensitivity of only 0.63. With a more stringent cutoff score (26), sensitivity was 0.92, specificity was 0.86, and classification accuracy was 90 percent.
The authors conclude that repetitive questioning is common in early dementia and uncommon in cognitively intact persons. Repetitive actions tend to be associated with more advanced dementia and are therefore not likely to be useful in screening for early dementia. Either the repetitive questioning item or the repetitive questioning and repetitive action items combined may be an effective abbreviated screening approach for early dementia, and one that can readily be adapted for use by family members.