Neurological subtle signs and cognitive development: a study in late childhood and adolescence

Neurological subtle signs (NSS) are often observed during the neurological examination of children and tend to disappear with age. Their persistence into late adolescence or young adulthood has been related to psychiatric and neurocognitive disorders. To provide a better understanding of their functional basis, a longitudinal correlational study with neurocognitive measurements was performed.

We conducted multiple regression and correlation analyses of NSS with demographic and cognitive measures on a subset of 341 healthy children (56% males), taking part in a longitudinal dental study. Participants, whose ages ranged between 11-15 years, at first evaluation, undertook yearly, during 5 years, a 6-item NSS exam (producing a total score ranging between 0-18) and a comprehensive battery of neurocognitive tests. Effects of age, gender, IQ, and 7 neurocognitive factors on NSS were analyzed.

Over the years, NSS scores correlated consistently with selective attention (Stroop test), motor speed (finger tapping), and visuomotor speed (pegboard speed).

These results suggest that the disappearance of NSS in late childhood and adolescence occurs primarily in parallel with the development of motor and visuomotor functions and secondarily in relation to higher order functions such as selective attention (Stroop) and executive control (B-A Trails difference).