Background: To elucidate significance of physical signs seen in excessive television-game (TVG) players complaining of unexplained persistent symptoms, a cross-sectional cohort study was designed.
Methods: A total of 1143 school children, aged between 6 and 11-years-old, and their parents were included in the study. Questionnaires were sent to guardians asking the number of hours that their children watched TV, TVG, and slept. All children were examined to check for three physical signs, black rings in the skin under the eye (BR), muscle stiffness in the shoulder (MS), and displacement of the scapula associated with muscle stiffness in the shoulder (DS/MS) by inspection and palpitation.
Results: The three signs, BR, MS and DS/MS, were present in 165 (14.4%), 229 (20.0%) and 72 (6.2%) children, respectively. Boys had greater frequencies of two signs than girls (BR, 19.6% vs 8.9%, P<0.01; MS, 26.1% vs 13.6%, P<0.01), respectively. Boys spent more time on TVG playing than girls (1.1+/-0.7 h/day vs 0.4+/-0.6 h/day, P<0.0001), respectively. Excessive TVG players, who spent > or = 1 h/day for TVG had greater frequencies of two signs, BR and MS, than those of non-TVG-players (18.9% vs 13.0%, P<0.05; 25.6% vs 14.4%, P<0.01), respectively. The TVG playing time correlated with two signs, BR (P=0.0143) and MS (P=0.0048). Furthermore, sleep deprivation related to three signs, BR (P=0.0078), MS (P<0.0001) and DS/MS (P=0.0290).
Conclusions: Excessive TVG playing links to the occurrence of BR and MS. Other factors, which cause sleep deprivation, may underlie in the occurrence of the three signs. The amount of time spent on TVG playing should be regulated to < 1.0 h/day.