As stated in the section in our paper on limitations, the Short Portable Mental Status Questionnaire (SPMQ) "is less sensitive in screening for cognitive impairment than longer instruments or structured interviews" [1]. The administration time must be addressed, however, when determining the usefulness of a screening instrument; shorter instruments take less time to administer. We specifically disagree with the suggestion that the SPMQ is an inadequate screening instrument for cognitive impairment. In the letter to the editor cited by Dr. Nardone, he and Dr. Gorman present a Table showing the test characteristics of various mental status examinations [2]. The likelihood-negative ratio of 0.07 reported for the 30-item Cognitive Capacity Screening Examination noted by Dr. Nardone is based on a study of 24 medical inpatients who had received psychiatric consultations, 18 (75%) of whom had an organic mental syndrome. In two studies of the more commonly used Mini-Mental Status Examination (MMSE), the likelihood-negative ratios reported were 0.16 and 0.23, respectively [2]. In a study of 282 consecutively hospitalized medical inpatients, 34 (12%) of whom had dementia [3], the likelihood-negative ratio for the SPMQ was 0.14, based on a cut-off of three errors on the SPMQ (which we used). If this ratio is used, the pre- to post-test probability with the SPMQ in our patient sample would change from 19% to 3%. Tests with likelihood-negative ratios in the range of 0.1 to 0.2 are considered to be useful in ruling out disease. Thus, the literature does support the usefulness of the SPMQ as a screening tool for cognitive impairment.

The administration time of the screening test is important to clinicians, but we have no data to address such differences between 10-item and 30-item instruments. Differences on the order of 3 to 5 minutes would clearly influence clinicians' choice of instruments. Lachs and colleagues [4] have suggested using a single screening item assessing short-term memory (sensitivity, 97%; specificity, 43%) as an initial screen for cognitive impairment, followed by the MMSE for those patients unable to recall all three items [4, 5]. This strategy may balance diagnostic accuracy with administration time. We agree with Dr. Nardone that clinicians should select a cognitive screening strategy that is based "on the patient setting, the desired cutoff for a positive/negative test, and whether the intent is to confirm the diagnosis of organic brain syndrome or rule it out" [2].