Evoked brain potentials in adolescents in normal conditions and in attention deficit during solution of tasks requiring recognition of short-duration acoustic stimuli

The feedback-related negativity (FRN) in adolescents

This study examined age-related differences in the ERP correlates of external feedback processing (i.e., the feedback-related negativity [FRN]) in adolescent and young adult males, using a simple gambling task involving unpredictable monetary losses and gains of low and high magnitude. The FRN was larger after losses than gains, and was modulated by the magnitude of gains, but not the magnitude of losses, for all participants regardless of age. FRN amplitude was larger in adolescents than adults and also discriminated relatively less strongly between gains and losses in adolescents. In addition, the morphology of the waveform after high losses suggests that feedback in this condition may have been processed less efficiently by adolescents. Our results suggest that, although the FRN in adults and adolescents share some common characteristics, the neural processes that generate the FRN are still developing in midadolescence. These findings are discussed in the context of adolescent risk taking.

Long-term deficits of preterm birth: evidence for arousal and attentional disturbances

OBJECTIVE

Quantitative measures of pre-attentional, attentional and frontal lobe processes were compared to evaluate quantitative measures of these deficits in Ex-Preterm vs. Ex-Term adolescents.

METHODS

We compared 43 Ex-Preterm with 26 Ex-Term adolescents using the P50 auditory potential, the Psychomotor Vigilance Task (PVT), a reaction time (RT) test, and Near Infrared Spectroscopy (NIRS).

RESULTS

The mean amplitude (+/-SE) of the P50 amplitude was similar in the Ex-Preterm (1.8+/-1.4 microV) vs. Ex-Term adolescents (1.8+/-0.6 microV, df = 68, F = 0.05, p = 0.8), but the Ex-Preterm group showed a trimodal distribution in amplitude (High, 3.3+/-0.4 microV, df=42.25, F=19.2, p < 0.01; Medium, 1.7+/-0.1 microV, df = 39, F = 0.41, p = 0.53; Low, 0.7+/-0.1 microV, df = 40, F = 49.5, p < 0.01) suggested by statistically significant variance between populations (Kolmogorov-Kuiper test, df = 42.25, F = 5.4, p < 0.01). Mean RT was longer in Ex-Preterm (250+/-8 ms) vs. Ex-Term subjects (200+/-5 ms, df = 68, F = 18.8, p < 0.001). PVT lapses were increased in Ex-Preterm subjects, and varied inversely with P50 amplitude (Overall Mean 17+/-5 lapses, df = 67, F = 5.34, p < 0.05; Low P50 amplitude, 25+/-10, df = 40, F = 8.8, p < 0.01; Medium, 21+/-11, df = 38, F = 5.37, p < 0.05; High, 6+/-2, df = 39, F = 6.78, p < 0.01) vs. Ex-Term subjects (2+/-0.4 lapses, p < 0.01). NIRS levels did not differ statistically, but tended to correlate with P50 amplitude in the Ex-Preterm group.

CONCLUSIONS

These findings suggest differential pre-attentional, attentional and frontal lobe dysfunction in Ex-Preterm adolescents.

SIGNIFICANCE

These measures could provide a means to objectively assess differential dysregulation of arousal and attention in Ex-Preterm adolescents, allowing optimization of therapeutic designs.