[Neurological and neuropsychological characteristics of the functional turn in the critical preschool period].

A total of 124 preschool children aged 5 to 6 years attending kindergartens or placed into children's homes were subjected to neurologic and neuropsychologic examinations. The alterations revealed were inconclusive and of various kinds. On the one hand, they were characterized by an increase by 5 to 6 years of age in the frequency of the minimal signs of pyramidal and cerebellar failure and of the phenomenon of mirror movements and writing. On the other hand, those alterations were marked by improved readings of the higher psychic functions. On electroneuromyography the interage differences were confirmed by a decrease of the motosensory ratio in children aged 5 years as compared to those aged 4 and 6 years. The alterations described were given the name of the "functional turn" which as the most important stage in the critical preschool period includes both progressive evolutionary jump and functional unbalance associated with rearrangement of the functions of the body or a system.