Atypical automatic processing of interoceptive information in adolescents with alexithymia

Background

Alexithymia, characterized by impaired emotional identification and expression, exhibits conceptual and neuroanatomical overlap with atypical interoception - the ability to perceive and process bodily signals. This study investigates in adolescents the link between alexithymia and interoception using the heartbeat-evoked potential (HEP), a brain response reflecting cardiac signal processing.

Methods

Forty-seven healthy subjects (mean age 14.29 years, 53.2% female) underwent HEP recordings across three conditions (an interoceptive task, facial emotion recognition task, and resting condition) and completed the Toronto Alexithymia Scale (TAS-20).

Results

Frontocentral right hemisphere HEP activity during the interoceptive task displayed a negative correlation with TAS-20 total score. The HEP measured in the same area showed a non-significant trend for a negative correlation with two TAS-20 subscales. No significant correlation was observed between alexithymia scores and HEP amplitudes during the other conditions. TAS-20 scores had no significant association with the performance in an interoceptive task.

Limitations

Generalizability to adults is limited due to ongoing emotional and interoceptive network maturation in adolescents. HEP is only an indirect marker for interoceptive processes; therefore, no causality can be implied. Alexithymia self-reports could be critical, as individuals with higher levels of alexithymia exhibit more difficulties in discerning their internal emotional states. Power sensitivity analysis revealed a slightly underpowered sample.

Conclusion

This study suggests altered neuronal processing of bodily signals during interoception in adolescents with higher alexithymia scores. Our findings are novel, as they are the first to exhibit an interaction in this direction, thus highlighting the relevance of interoceptive processing in alexithymia.