It is a simple test, yet it tells clinicians so much about a patient’s cognitive health.
The instructions are straightforward: On a piece of paper, draw the face of a clock. Put in all the numbers and set the hands to 10 after 11.
A patient’s performance can give clinicians insight into a number of cognitive functions, including verbal understanding, memory and visuospatial abilities.
“The reason why clock drawing is such a powerful test is not because of how well you do it, it’s because of the myriad ways in which you struggle and might fail in your attempt to do it,” said David Libon, Ph.D., a geriatric neuropsychologist at Rowan University whose research has identified clock drawing test errors associated with particular dementia syndromes.
The test yields such rich information, Libon said, that his mentor, the late Edith Kaplan, Ph.D., a pioneer in clinical neuropsychology, used to say that if she was pressed for time and could give a patient only one cognitive test, it would be the clock drawing test.
Now, researchers led by Catherine Price, Ph.D., an associate professor of clinical and health psychology in the UF College of Public Health and Health Professions, and Patrick Tighe, M.D., an associate professor of anesthesiology and orthopaedics in the UF College of Medicine, are using the clock drawing test in a novel way. In a new National Institute on Aging-funded study of older adults who are undergoing surgery, participants will use a digital ballpoint pen to complete the clock drawing test at various points throughout a year. Because the pen records data at a rate of 80 times a second, it can reveal subtle cognitive changes that the clinician would not be able to spot.
Randall Davis, Ph.D., a professor of electrical engineering and computer science at the Massachusetts Institute of Technology, and Dana Penney, Ph.D., a neuropsychologist at Lahey Hospital &
Medical Center, developed the digital clock drawing test software, which is available through their company, Digital Cognition Technologies. Libon, Davis and Penney are also team members of the new UF-led study.
“With the digital test, you’re able to capture behavior and understand and analyze the process by which someone is thinking,” Penney said. “That gives you the ability to see changes in cognitive function before people are actually making mistakes.”
For example, the digital clock drawing test is so sensitive it can perceive patient pauses that may only be fractions of a second long. If the pauses happen at phases in the clock drawing where many people typically do not pause, it may be an early indicator of cognitive change.
“We can measure pauses with no additional effort on the part of either the person taking the test or the clinician, and yet we get these incredibly accurate and detailed analyses of issues of timing,” Davis said. “Those are quite revealing and can unmask the compensatory strategies people use, like pausing more often so they can gather their wits around them, to continue doing something that someone else would have done quickly and easily.”
The UF study data will be analyzed with machine learning algorithms to identify which behavioral features predict postoperative complications and outcomes, such as length of stay, hospital cost and readmission rates. The goal is to provide an efficient and accurate tool that becomes part of routine clinical practice, Tighe said.
“This study will help health care professionals identify and categorize patients’ cognitive difficulties that may influence decisions about the timing of surgery, surgical and anesthetic techniques, and postoperative recovery plans,” Tighe said.
