Researchers used a simple finger tapping test to discover that fine motor skill decline doesn't start until most people reach their mid-60s - unless they have abnormal conditions like Parkinson's disease, middle-aged people do just as well as young adults.

Priscila Caçola, an assistant professor of kinesiology at The University of Texas at Arlington, led her team in the study, which was published online and will be included in the June 2013 issue of the journal Brain and Cognition.

"We have this so-called age decline, everybody knows that. I wanted to see if that was a gradual process," said Caçola in a news release. "It's good news really because I didn't see differences between the young and middle-aged people."

The UT team's study used a process called chronometry, which times test participants' finger tapping movements as they imagine them, and then actually perform them. The idea behind this paradigm is that the brain makes a mental plan of movements before making them, and as motor skills decline, the time lag between imagining movements and executing them grows.

The study recruited 99 healthy participants aged 18 to 93, who were divided into three age categories: 18 to 32, 40 to 63, and 65 to 93. All of them completed a computer task linked to a finger tapping test, in which numbered stickers labeled their fingers from 1 through 5. In a series of increasingly difficult trials, the computer flashed a sequence of up to five numbers in various orders, which the participants had to match either by sequentially tapping their fingers or imagining doing so, then saying "stop" when they finished.

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A model of the finger-tapping test. [Credit: UT Arlington]

The results showed that the middle-aged group's performance on the finger tapping test was only slightly lower than that of the young group, and that the oldest group showed a significant drop in fine motor ability.  

"What we found is that there is a significant drop-off after the age of 64," said Jerroed Roberson, an undergraduate who co-authored the paper, in the news release. "So if you see a drop-off in ability before that, then it could be a signal that there might be something wrong with that person and they might need further evaluation."

The researchers write in their paper that though fine motor skill decline has been extensively studied in older adults, this is the first study that observes when movement deficits in the finger tapping test begin.

Caçola hopes the findings can help neurologists identify abnormal loss of function in patients who have not yet reached their 60s, and that future studies can identify methods for older adults to train fine motor movements in order to slow age-related decline.

"The important message here is that clinicians should be aware that healthy older adults are slower than younger adults, but are able to create relatively accurate internal models for action," the study said.

Poor fine motor skills have been linked to lack of physical activity in children, and movements can also influence perception. Recent findings suggest that older adults can learn new motor skills, and that remaining socially active  helps keep motor skills sharp in old age.