In Search of Lost Time: The Clock Test in Patients With Cognitive Decline

Andrew N. Wilner, MD


August 10, 2016

Simple Test for Cognitive Concerns

Perhaps no neurologic disorder is feared more than Alzheimer dementia. At least a few times a week, a concerned elderly man or woman comes to my office wondering whether their forgetfulness or loss of attention heralds descent into cognitive oblivion. Often, it is merely a case of the "worried well" or a relative obsessing over the imperfections of a loved one's aging memory. But sometimes my examination confirms a pathologic loss of cognitive skills.

The Big Hand and the Little Hand

What time is it? While seemingly an innocuous question, the patient's answer conveys deep meaning to a neurologist. Clock drawing has been recognized as a valuable tool to differentiate normal from abnormal cognitive functioning for more than 50 years.[1] In the office, I often engage this quick test.

While one may take the ability to tell time and draw a clock for granted, this deceptively simple task requires a fair amount of cognitive power. In order to properly draw a clock, the patient must listen attentively and follow instructions, visualize a clock face from memory, place the hours in their proper sequence, plan and execute appropriate spacing, and graphically indicate the time with the clock's two hands.

Patient Case

The clock test is by no means a complete mental status exam, but it can be extraordinarily revealing. For example, the clock below (Figure) was drawn by an 80-year-old woman whose children thought she had memory trouble. During our interview, she was a bit vague and made minor mistakes with simple calculations. Her neurologic exam was otherwise normal. She was asked to draw a clock to show the current time, which was 3:09 PM.

Figure. Drawing of a clock by 80-year-old patient with evidence of cognitive impairment.

Although scoring the clock test is somewhat subjective, two of my behavioral neurology colleagues readily agreed that her clock revealed evidence of cognitive impairment. It was very spare in detail, much like the content of her speech. She drew only the number 3, which, although correctly placed, was excessively small. Rather than indicate minutes with the large hand of the clock, she drew nine dashed lines. One could see that she grasped the idea of "9 minutes past 3," yet her representation was unconventional and abnormal. A few weeks later, when I received the results of her detailed neuropsychologic exam, which took several hours to administer and interpret, the conclusion confirmed what I had learned in my 1-minute clock test: "mild inefficiency of attention and memory."

A Time to Be Born and a Time to Die

An essential dimension of humanity is our place in the universal timeline. We are defined by our birth date and traditionally celebrate it. Western astrology keys the position of the planets, moon, and sun to the moment of birth. When we die, a tombstone, engraved with name and date, marks our grave. Ancient cultures, such as the Mayans and Chinese, expended great efforts to construct accurate calendars in order to track time. Journalists learn early on the importance of a story's "five W's": Who, What, Where, Why, and When. Without "when," the story remains incomplete.

Alzheimer disease unhinges the body from the celestial rhythm of night and day, resulting in sleepless nights and aimless wandering. The passage of time, an undeniable but abstract concept, becomes increasingly difficult for a person with dementia to appreciate. Without a sense of time, memories become random and lose their relevance. One cannot even dress oneself if it is no longer obvious that socks must come before shoes. Along with an ability to pay attention, reason, and problem-solve, a sense of time is critical to our functioning as human beings. How can one plan for the future if there is none?

Do you know what time it is?