TY - JOUR
T1 - Circadian rhythm in handwriting
AU - Jasper, Isabelle
AU - HÄußler, Andreas
AU - Marquardt, Christian
AU - HermsdÖrfer, Joachim
PY - 2009/6
Y1 - 2009/6
N2 - 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.
AB - 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.
KW - Circadian rhythm
KW - Handwriting
KW - Kinematic analysis
KW - Sensorimotor control
KW - Sleep deprivation
UR - http://www.scopus.com/inward/record.url?scp=65749089046&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2869.2008.00727.x
DO - 10.1111/j.1365-2869.2008.00727.x
M3 - Article
C2 - 19645970
AN - SCOPUS:65749089046
SN - 0962-1105
VL - 18
SP - 264
EP - 271
JO - Journal of Sleep Research
JF - Journal of Sleep Research
IS - 2
ER -