AI Article Synopsis
- The study explored how handwriting is affected by circadian rhythms in nine young male subjects undergoing sleep deprivation.
- Handwriting performance was assessed through speed, fluency, and script size every three hours, revealing significant tempo changes linked to body clock cycles, especially around melatonin secretion.
- Despite differences in speed and variability, overall writing fluency remained stable, indicating that basic handwriting skills are maintained, even after a lack of sleep.
Article Abstract
The aim of the present study was to determine whether the motor process of handwriting is influenced by a circadian rhythm. Nine healthy young male subjects underwent a 40-h sleep deprivation protocol under constant routine conditions. Starting at 09:00 hours, subjects performed every 3 h two handwriting tasks of different complexity. Handwriting performance was evaluated by writing speed, writing fluency and script size. The frequency of handwriting, as a measure of movement speed, revealed a circadian rhythm, validated by harmonic regression, with a slowing at the time of the onset of melatonin secretion (22:17 hours) and a trough in the very early morning at around 03:30 hours. In the temporal variability of handwriting an effect of task complexity was suggested in the direction of circadian variations in parallel with speed only for the sentence. Despite deficits of speed and temporal variability, writing fluency did not change significantly across sessions indicating that the basic automation of handwriting was preserved at any time. On the second day, daytime levels of the kinematics of handwriting did not reflect impaired performance after sleep deprivation. Our results show for the first time a clear circadian rhythm for the production of handwriting.
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| http://dx.doi.org/10.1111/j.1365-2869.2008.00727.x | DOI Listing |
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