Complexity of electrodermal activity to mental stress is changed during adolescent age-period.

Complexity characterizes behaviour of all physiological systems whose components interact in multiple ways usually quantified by entropy techniques. However, complexity analysis regarding electrodermal activity (EDA)-related sympathetic cholinergic nervous system is rare. Thus, we aimed to study EDA dynamics complexity changes from aspect of various embedding dimensions (m) and timescales (τ) (sample entropy (SampEn) with m ∈ <2,7>, and multiscale entropy (MSE) in τ ∈ <1,20>) in association with traditionally used EDA indices (skin conductance level (SCL) and non-specific skin conductance responses (NS.SCRs)) to mental stress (mental arithmetic test - MAT) in healthy participants at critical adolescent age. The cohort (total group) consisted of 60 adolescents (17.5 ± 0.5 yrs) divided into three groups: Group-1: early (13.1 ± 0.3 yrs), Group-2: middle (16.6 ± 0.2 yrs) and Group-3: late (22.9 ± 0.1 yrs) adolescence. SampEn (m > 2) and MSE (for all τ) were significantly higher during MAT than baseline in total group and Group-2 (p < 0.05). Index MSE for all τ was significantly higher during MAT than baseline in total group, and Group-2; for τ ∈ <2,13> in Group-1 (p < 0.05). Additionally, while SCL was significantly higher during MAT than baseline in all groups, NS.SCRs was lower during stress only in Group-3 (p < 0.05). In conclusion, this study revealed distinct EDA complexity characteristics in individual examined groups indicating importance of complexity evaluation in stress-related sympathetic regulatory mechanisms within individual adolescent age ranges.