Identifying cognitive impairment during the Annual Wellness Visit: Who can you trust?
This study found that patients, family members, and even physicians have trouble detecting cognitive impairment. A better bet: Routinely administer an objective cognition test.
Patient self-ratings did not correlate (r=0.02) with dementia severity or with any of the 3 standardized memory tests. Informant scores correlated modestly with dementia severity and memory tests, but were significantly higher (P<.001) than those of the patients. Both the MOST (r=–0.86) and the MMSE (r=–0.76) had much stronger and highly significant (P<.001) correlations with dementia severity and with the memory measures (r=0.49–0.70). In addition, the MOST and MMSE were significantly (P<.001) better correlated with dementia severity and objective memory scores than were the informant ratings. Only the MMSE correlation with visual recall (P=.06) did not surpass that of the informant.
The MOST had a significantly higher correlation than the MMSE with dementia severity (P<.01) and with each of the 3 memory tests (P<.05). The MOST and MMSE scores were not related to level of depression (r=–0.01 and –0.03). Patient reports correlated significantly with depression level (r=–0.40; P<.001) as did those of the informants (r=–0.22; P<.01). Nevertheless, depression did not appear to be responsible for the limited relationship between patient self-ratings and objective test scores for cognition. When clinically depressed (GDS≥7) patients were removed from the analysis (remaining n=166), there was no significant improvement in the correlation between subjective ratings and objective scores.
We conducted a secondary analysis of patients whose cognition ranged between normal and mild-to-moderate dementia to see if more cognitively intact individuals would be more accurate at self-rating. In this subsample (n=127; mean age=77.3 years; 57% females), patient self-reports again did not correlate significantly (r=0.05) with dementia severity. Informant ratings remained modest, but significant (r=–0.25; P=.004) and statistically better (P<.05) than those of the patients. The MOST (r=–0.69; P<.001) and the MMSE (r=–0.54; P<.001) remained well-correlated with dementia severity and again outperformed the informant ratings (MOST, P<.001; MMSE, P<.05).
TABLE 1
Cognition diagnoses and severity levels in 201 consecutively evaluated elderly patients
| Diagnosis | n (%) |
|---|---|
| Normal cognition | 8 (4.0) |
| Mild cognitive impairment | 32 (15.9) |
| Dementia of all types | 161 (80.1) |
| – Alzheimer’s disease | 90 (55.9) |
| – Vascular dementia | 62 (38.5) |
| – Frontotemporal dementia | 4 (2.5) |
| – Other dementia | 5 (3.1) |
| Dementia severity rating | |
| Normal (0) | 8 (4.0) |
| Mild cognitive impairment (0.5) | 32 (15.9) |
| Mild dementia (1.0) | 42 (20.9) |
| Mild-moderate dementia (1.5) | 45 (22.4) |
| Moderate dementia (2.0) | 38 (18.9) |
| Moderate–severe dementia (2.5) | 27 (13.4) |
| Severe dementia (3.0) | 9 (4.5) |
TABLE 2
Mean test scores for predictor and outcome variables
| Predictor variables | Mean (SD) | Outcome variables | Mean (SD) |
|---|---|---|---|
| MOST | 15.5 (5.7) | Dementia Severity Rating | 1.5 (0.8) |
| MMSE | 23.2 (4.7) | LM-II | 6.4 (8.2) |
| VACS-P | 35.6 (8.4) | VR-II | 5.4 (7.7) |
| VACS-I | 27.6 (10.2) | SLT-R | 4.3 (3.1) |
| GDS-15 | 3.3 (3.3) | ||
| GDS-15, Geriatric Depression Scale-15; LM-II, Logical Memory-II; MMSE, Mini-Mental State Examination; MOST, Memory Orientation Screening Test; SD, standard deviation; SLT-R, Shopping List Test-Recall; VACS-I, Visual Analog Cognition Scale- Informant; VACS-P, Visual Analog Cognition Scale-Patient; VR-II, Visual Recall-II. | |||
TABLE 3
How the MOST, MMSE, and VACS predictor variables compared with outcome measures
| Correlations of MOST, MMSE, VACS-P, and VACS-I to criterion measures | Pairwise comparison of correlations of MOST, MMSE, and VACS-I to criterion measures (absolute values) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MOST (n=201) | MMSE (n=201) | VACS-P (n=194) | VACS-I (n=181) | MOST vs MMSE | MOST vs VACS-I | MMSE vs VACS-I | ||||||||
| Pearson’s correlation coefficient (P value*) | Z-ratio (P value*) | |||||||||||||
| r | P | r | P | r | P | r | P | Z | P | Z | P | Z | P | |
| Dementia severity | –0.86 | <.001 | –0.76 | <.001 | 0.02 | .78 | –0.36 | <.001 | 2.835 | .005 | 8.723 | <.001 | 5.954 | <.001 |
| LM-II | 0.67 | <.001 | 0.52 | <.001 | –0.03 | .68 | 0.20 | .007 | 2.245 | .025 | 5.72 | <.001 | 3.533 | <.001 |
| VR-II | 0.65 | <.001 | 0.49 | <.001 | –0.02 | .78 | 0.33 | <.001 | 2.481 | .013 | 4.29 | <.001 | 1.872 | .061 |
| SLT-R | 0.70 | <.001 | 0.56 | <.001 | 0.01 | .89 | 0.28 | .001 | 2.223 | .026 | 5.735 | <.001 | 3.564 | <.001 |
| GDS-15 | –0.01 | .89 | –0.03 | .67 | –0.40 | <.001 | –0.22 | .003 | ||||||
| GDS-15, Geriatric Depression Scale-15; LM-II, Logical Memory II; MMSE, Mini-Mental State Examination; MOST, Memory Orientation Screening Test; SLT-R, Shopping List Test-Recall; VACS-I, Visual Analog Cognition Scale-Informant; VACS-P, Visual Analog Cognition Scale-Patient; VR-II, Visual Recall II. *The minimum acceptable measure of statistical significance was .05. Pearson’s correlation coefficient (at left) measures the strength of relationship between 2 variables. It can range from 0.0 (no correlation) to –1.0 or 1.0 (perfect correlation). The larger the number, the stronger the relationship. A negative coefficient indicates an inverse relationship. Z-ratio (at right) reflects the size, or magnitude, of the difference between 2 correlations. | ||||||||||||||
DISCUSSION
Results of this study demonstrate that patients referred for specialized memory evaluation had virtually no idea of the degree of their cognitive impairment. Patients, on average, rated their function in 5 critical areas of cognition and behavior as “good.” While 80% of these patients demonstrated dementia on formal evaluation, more than 95% rated themselves as having good or very good cognition. Their ratings did not correlate with any objective memory measures or expert clinician opinion.
Patient and informant ratings are unreliable. Patients with better cognition, who might visit their doctor alone for the Annual Wellness Visit and would appear more intact, were no better at judging their cognition than the total patient sample. Both the patients with good cognition and those with dementia rated themselves equally unimpaired. This finding is not unique to the visual analog scale that we used in this study. When 148 self-nominated “cognitively healthy” community-dwelling elders took the MOST and a battery of neuropsychological tests as part of a norming study for the MOST,31 more than 20% would be classified as having dementia based on their memory and executive function test scores. These findings strongly suggest that patients cannot be relied on to inform their physician of cognitive impairment.
