Measured Factor Detail
Abbreviated Mental Test (AMT4) score is constructed using the following items such as Age, Date of birth, Place and Year. The patient is asked to state each of the above item. Each question correctly answered scores one point. AMT4 score of less than four indicates impaired cognition.
Measured Factor Low Impact
- AMT-4 score less than 4 suggests cognitive impairment at the time of testing, although further and more formal tests are necessary to confirm a diagnosis of dementia, delirium or other causes of cognitive impairment
Measured Factor High Impact
- A score above 4 indicates normal cognition.
- Critical Low: Less than 4
- Normal: 4
- Normal Adult Male: 4
- Normal Adult Female: 4
- Normal Geriatric Male: 4
- Normal Geriatric Female: 4
Study Validation 1
The present study evaluated the ability of the AMT4 to identify impaired mental status in the emergency department (ED), defined as positive scores on either the Confusion Assessment Method-ICU for delirium, the standardized Mini Mental State Examination as a general cognitive screener or the eight-item Interview to differentiate aging and dementia from dementia. Of 196 adults at least 70 years of age (mean: 78.5±5.9), the AMT4 had a sensitivity of 0.53 (0.42-0.63) and a specificity of 0.96 (0.89-0.99) for impaired mental status in the ED. The AMT4 was positive in almost all patients (92%; 24/26) screening positive for delirium, but less than half (47.8%; 22/46) of those screening positive for probable dementia, and less than a quarter (22.2%; 6/27) of those screening positive for probable cognitive impairment. The outcomes of the study demonstrate a limited sensitivity of the AMT4 in identifying the majority of cognitively impaired patients and restricts its use in isolation as a general cognitive screener in the ED.
Study Validation 2
This study was performed to determine the utility of the 4-item Abbreviated Mental Test (AMT4) for detecting cognitive impairment in accident and emergency patients aged 65 years or older. Cognitive function was assessed using the Mini Mental State Examination (MMSE), 4 and 10-point AMT and subjective judgment. Amongst 601 patients, 226 (37.6%) scored 23 or less on MMSE. Cutoffs of 3 or less for AMT4 and 7 or less for AMT had sensitivities of 80% [95% confidence interval (CI): 0.75-0.85] and 76% (95% CI: 0.69-0.81), and specificities of 88% (95% CI: 0.84-0.91) and 93% (95% CI: 0.90-0.96), respectively, for detection of cognitive impairment; subjective judgement of admitting nurse had 50.5% (95% CI: 44-57%) sensitivity and 98.6% (95% CI: 0 96-1.00%) specificity. The study concluded that AMT4 as well as the 10-point AMT performs accurately in screening for cognitive impairment and assists in the early detection of cognitive problems.
Study Validation 3
The four-question abbreviated mental test (AMT4) has been promoted in the acute setting as a pivotal assessment tool. In the present study 100 acute medical admissions (>60 years old) with a negative AMT4 were evaluated with the AMT10, six-item cognitive impairment test (6CIT) and confusion assessment method (CAM) within 24 hours of admission. The results demonstrated that nearly half of the participants had signs of cognitive impairment despite a negative AMT4 culminating to a risk of under diagnosis with potentially serious consequences for morbidity and mortality. Tests of short term memory were strongly associated with cognitive impairment. The study proposed the inclusion of such a test in order to increase the sensitivity of the AMT4 without compromising its brevity and utility in the acute setting.
Study Additional 1
A study was conducted in 500 patients with mean age 83 years. They were assessed clinically for diagnoses of definite or possible dementia. It was identified that 93 of 500 (18.6%) had definite delirium, 104 of 500 (20.8%) had possible delirium and 277 of 500 (55.4%) did not suffer from delirium and 266 of 500 (53.2%) suffered from definite or possible dementia. For diagnosis of definite delirium, AMT-4 had a sensitivity of 92.7% (95% confidence interval (CI): 84.8-97.3), with a specificity of 53.7% (95% CI: 48.1-59.2); AMT-10 (<4/10), MOTYB (<4/12) and SQiD showed similar performance. bCAM had a sensitivity of 70.3% (95% CI: 58.5-80.3) with a specificity of 91.4% (95% CI: 87.7-94.3). 4AT (>4/12) had a sensitivity of 86.7% (95% CI: 77.5-93.2) and specificity of 69.5% (95% CI: 64.4-74.3). The study concluded that screening tools such as AMT-4 or MOTYB have acceptable sensitivity for definite delirium, but poor specificity hence these tools may be used at initial stage in assessment for delirium.
Study Additional 2
The study aimed to describe test accuracy of brief screening tools for diagnosis of cognitive impairment and delirium in acute stroke over a 10-week period in 111 subjects. Subjects were 50% male (n=55), and median age was 74 years (interquartile range, 64-85). The study concluded that AMT-4, AMT-10, and SQ all had excellent (1.00) specificity for detection of cognitive impairment, although sensitivity was poor (all <0.60). The 4AT had greatest sensitivity for detecting delirium (1.00 [confidence interval [CI], 0.74-1.00]) and reasonable specificity (0.82 [CI, 0.72-0.89]).
Study Additional 3
An audit using the abbreviated mental test (AMT) and Confusion Assessment Method (CAM) tools assessed 28 elderly emergency department (ED) patients for the presence of delirium. The results demonstrated that prevalence rate of delirium in elderly ED patients was similar to those reported in the literature. The audit demonstrated the importance of cognitive assessment, as cognitive changes can be an early and sensitive indicator of physiological dysfunction. However, the AMT had limitations which inhibited its use in ED. A four question version known as the AMT4 may be more suitable.