The MMS was given to two groups of people that we will refer to as Samples A and B. In Sample A (Table 1) are 69 patients chosen specifically as clear examples of clinical conditions (29 with dementia syndromes due to a variety of brain diseases, 10 with affective disorder, depressed type with clinically recognizable(SIC) cognitive impairment, 30 with uncomplicated affective disorder, depressed type) and 63 normal, elderly persons similar in age to the patients. All the patients were tested shortly after admission to the New York Hospital Westchester Division, a private psychiatric hospital and the normal subjects were tested at a Senior Citizens Center and at a retirement apartment complex. Thirty-three of the 69 patients in Sample A were retested after treatment. The patients with dementia were treated according to their clinical conditions. They occasionally received tricyclic antidepressants or phenothiazines as well as treatment for medical illnesses. The patients with depression were treated with antidepressants and/or ECT. They also may have received medical treatments.

Sample B (Table 2) is a patient group formed by taking consecutive admissions to the hospital and giving them the MMS shortly after admission. It was intended to be a standardization sample and came eventually to consist of 137 patients (9 patients with dementia, 31 patients with affective disorder, depressed type, 14 patients with affective disorder, manic type, 24 with schizophrenia, 32 with personality disorder with drug abuse, and 27 with neurosis). These diagnoses were made by M.F. on review of the hospital chart employing the diagnostic criteria described below and without knowledge of the MMS scores. Subsets of patients from both Samples A and B were extracted for age-matched studies (Table 1B) concurrent validity (Table 3) and test-retest reliability (Table 4).

The following diagnostic criteria were used for both Sample A and B:

Dementia. A global deterioration of intellect in clear consciousness.

Affective disorder, depressed type, uncomplicated. A sustained feeling of depression with an attitude of hopelessness, worthlessness or guilt and with no notable cognitive defect.

Affective disorder, manic type. A sustained feeling of elevated mood with an attitude of overconfidence or exaggerated self-importance.

Schizophrenia. Either Schneider’s first rank symptoms in the absence of affective symptoms or the presence of a personality deterioration associated with thought disorder and emotional incongruence without first rank symptoms.

Personality disorder with drug abuse. Absence of all above symptoms with a history of drug abuse, including alcohol.

Neuroses. Presence of psychological symptoms appearing to arise from the combination of a particular life situation and vulnerable character but with the specific absence of symptoms characteristic of the other syndromes.

The MMS is reliable on a 24 hr or 28 day retest by single or multiple examiners. When the Mini-Mental Status was given twice, 24 hr apart by the same tester on both occasions, the correlation by a Pearson coefficient was 0.887. Scores were not significantly different using a Wilcoxon T. To note examiner effect on 24 hr test retest reliability the MMS was given twice, 24 apart by two examiners. The Pearson r remained high at 0.827. The scores did not change; Wilcoxon T was not significant (Table 4). Thus the scores seem stable even when multiple examiners are used, the practice effect is small.

When elderly depressed and demented patients chosen for their clinical stability were given the Mini-Mental Status twice, an average of 28 days apart, there was no significant difference in these scores by the Wilcoxon T and the product moment correlation for test 1 vs test 2 was 0.98. (See Table 4.)

The MMS is a valid test of cognitive function. It separates patients with cognitive disturbance from those without such disturbance. Its scores follow the changes in cognitive state when and if patients recover. Its scores correlate with a standard test of cognition, the Wechsler Adult Intelligence Scale (WAIS).

Before considering its uses, it is an elementary but important point that as with an examination of cognitive performance, the MMS cannot be expected to replace a complete clinical appraisal in reaching a final diagnosis of any individual patient. Cognitive difficulties arise in a number of different clinical conditions. This is demonstrated by the overlapping of scores on the MMS in several categories here. Accurate diagnosis, including appraisal of the significance of cognitive disabilities documented in the MMS, depends on evidence developed from the psychiatric history, the full mental status examination, the physical status and pertinent laboratory data.

But the MMS does have a number of valuable features for clinical practice even though it cannot carry alone the diagnostic responsibility. As it is a quantified assessment of cognitive state of demonstrable reliability and validity, it makes more objective what is commonly a vague and subjective impression of cognitive disability during an assessment of a patient. It can provide this quantification easily requiring only a few minutes to complete. It can be repeated during an illness and shows little practice effect. Thus it is ideal for initial and for serial measurements of this important aspect of mental functioning and can demonstrate worsening or improvement of this feature over time and with treatment.

As with any other quantified assessment of cognitive function such as the WAIS with which it correlates so well, the MMS permits comparisons to be drawn between intellectual changes and other aspects of mental functioning. We have found it particularly useful in documenting the cognitive disability found in some patients with affective disorder (Post’s pseudodementia) and the improvement of this symptom with appropriate therapy for the mood disorder. Other applications that demand a quantitative assessment of cognitive function might be expected.

The MMS as it is extracted from the clinical examination has an advantage in assessment of patients and clinical problems not so obvious in tests such as the WAIS that are designed for other purposes such as prediction of school or occupational performance. Thus failures in the MMS on orientation, memory, reading and writing have much clearer implications than do failures in digit symbol, picture completion or vocabulary subtests of the WAIS in terms of a patient’s capacity to care for himself. These implications from the MMS score are easily appreciated by other professionals such as lawyers, judges and social workers concerned with such issues as the patient’s competency to manage his daily affairs. It can therefore aid in bringing to the patient the social supports that he needs.

Finally we have found the MMS useful in teaching psychiatric residents to become skillful in the evaluation of the cognitive aspects of the mental status. It provides them with a standard set of questions replacing what is often a bewildering variety of individual approaches. Those questions that it employs have obvious clinical pertinence and cover most of the categories of cognitive disability. Since it can be done quickly and gives a score it draws the resident’s attention to global improvements or declines in cognitive state. It also though because special attention is focused on memory and language functions will reveal the partial cognitive disabilities seen in the aphasic and the amnestic syndromes. As it becomes a routine, we have found an increase in resident interest and competence in assessing and managing the conditions that affect cognitive functioning such as dementia and delerium.

When given to 60 patients with dementia, depression with cognitive impairment, and depression (Sample A), the test proved to be valid and reliable. It was able to separate the three diagnostic groups, it reflected clinical cognitive change, it did not change in patients thought to be cognitively stable, and it was correlated with the WAIS scores. Standardization of the test by administration to 63 normal elderly subjects and 137 patients (Sample B) indicated that the score of 20 or less was found essentially only in patients with dementia,. delerium, schizophrenia or affective disorder and not in normal elderly people or in patients with a primary diagnosis of neurosis and personality disorder. The Mini-Mental Status was useful in quantitatively estimating the severity of cognitive impairment, in serially documenting cognitive change, and in teaching residents a method of cognitive assessment.

Acknowledgement - Supported in part by the general research funds, University of Oregon, Health Sciences Division.

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