Telling Time -
How Researchers are Studying the Aging Process

Part one described the research of Drs. Nelson Gruber and Roy Varner, Harris County Psychiatric Center (HCPC) psychiatrists, who were principal investigators in a study of the effectiveness of clock drawing tests to assess for cognitive impairment in geriatric psychiatric patients.

The specific research which Drs. Gruber, Varner and their colleagues conducted was a comparison of the clock drawing test (CDT) to the Pfeiffer Short Portable Mental Status Questionnaire ("Pfeiffer"), an established and more traditional brief neuropsychological test, known for its efficacy as an assessment of cognitive impairment in older adult psychiatric patients.

"We used the Pfeiffer to establish the presence and degree of cognitive impairment and then administered the CDT to compare its findings with the Pfeiffer. We wanted to see if both tests gave similar results, and we were also trying to determine if the claim of a previous study (by Wolfe-Klein, 1989, an original effort using clock drawing to screen for Alzheimer's disease) - that an abnormal CDT in an elderly person was almost always associated with Alzheimer's disease - also held true with an elderly psychiatry (geropsychiatry) outpatient population," he explains. "In other words, could the CDT predict Alzheimer's disease in people over 65 with a mental disorder as well as it did with an elderly population (seen at a geriatric medical clinic) who had no serious psychiatric diagnoses."

The 145 patients in Drs. Gruber and Varner's study were all outpatients at MSI's geropsychiatry clinic, ranging in age from 54 to 88 years old, with an average of 10 years of formal schooling. Eighty percent of the patients represented a wide variety of psychiatric disorders. The other 20 percent had some form of organic mental disorder (such as dementia) caused by physical conditions. Only 7 percent of the total group of 145 was diagnosed as having Alzheimer's disease.

All patients were given both the Pfeiffer and the CDT. (The Pfeiffer consists of questions such as "Who is the President? What's your mother's maiden name? What day is it?".) The researchers found that patients' results on the CDT corresponded well with the findings of the more established Pfeiffer screen as an indicator of cognitive impairment.

"We concluded," says Dr. Gruber, "that a normal clock drawing almost always predicts that a person's cognitive abilities are intact, whether he or she is a geriatric psychiatry patient or a geriatric medicine patient. Also, we concluded that mild cognitive impairment as shown in the Pfeiffer score, might not influence the person's clock-drawing ability. And, finally, we believed that age interacts with psychiatric illness to influence clock-drawing ability in geropsychiatry patients; the older our patients, the worse their clock drawings were.

"But the most curious finding in our study," he says, "was that group of 26 patients out of the 121 who had normal Pfeiffer scores, yet drew abnormal clocks. The CDT, when used with elderly psychiatric patients, was picking up something else that the Pfeiffer hadn't. In our study, these 26 patients without cognitive-intellectual impairments - as shown by their passing score on the Pfeiffer test - accounted for more than half of the total number of all the abnormal clock drawings (44) done by the 145 participants.

"So, we then hypothesized that it was the presence of significant psychiatric illness, rather than a dementing process (like Alzheimer's disease) in our patients, combined with their ages, that accounted for the abnormal clocks of those patients who had normal scores on the Pfeiffer test. Differences in individuals' illnesses, such as severity, chronicity, and treatment resistance, might also explain why some of these patients had trouble with the clocks and others didn't," says Dr. Gruber.

Dr. Gruber and his colleagues also speculated that the 26 patients who drew abnormal clocks but were cognitively intact might have a specific problem with Executive Skills, because other studies have associated this problem with primary functional psychiatric disorders such as depression and schizophrenia. "Executive Skills," explains Dr. Gruber, "are functions of the frontal lobe connections of the brain that control such mental skills as initiating ideas or actions, planning, and developing strategies.

"Given these results, our study was unable to confirm the Wolfe-Klein study's correlation between abnormal clock drawings and Alzheimer's disease," he says.

"Wolfe-Klein tested a larger sample of general geriatric patients without major psychiatric disorders, while we used a smaller sample of geriatric patients, all with psychiatric disorders, most of them not related to dementia or to a medical problem."

But, Dr. Gruber says, the unexpected results suggest that you have to be careful how the results are used and interpreted; specifically: when you use the same test, don't expect the same outcomes when it's used in different settings with a different population.

Dr. Gruber says he would like to do more research efforts to clarify the usefulness of the clock drawing test, specifically to see how geropsychiatric patients with specific illnesses such as schizophrenia, major depression - both inpatient (HCPC) and outpatient settings, perform on the clock drawing test.

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©2006 Texas Medical Center

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