WASHINGTON – Insomnia may feel awful from head to toe, but the effects might not translate to actual performance.

A study conducted by the University of California, San Diego examined 50 people – 25 normal sleepers and 25 who complained of insomnia. All were asked to take a test involving the processing and storing of short-term memory, the Wall Street Journal reports.

Everybody did equally well, including the poor sleepers.

When researchers talked to the subjects after, those who had trouble sleeping said it simply felt like the tests were harder.

Brain imaging technology seemed to confirm that poor sleepers used a different part of their brain to tackle the difficult questions than the normal sleepers did. Those with insomnia couldn’t switch off the area of their brain that’s usually inactive while working toward a goal.

More research is needed, though, to determine why. The study appears in the scientific journal Sleep.

WTOP’s Alan Etter contributed to this report.