Cette étude pilote cherche à tester la faisabilité de l’entraînement à la cohérence cardiaque avec des personnes atteintes d’un retard intellectuel dans le cadre d’un atelier protégé. Un entraînement à la cohérence cardiaque est proposé aux participants volontaires pour une durée de deux semaines à la prise de travail, matin et après-midi. Une appréciation des effets de ces exercices respiratoires est effectuée avant et après entraînement par la mesure d’indices de variabilité cardiaque et une évaluation de la perception du stress professionnel. La comparaison des valeurs récoltées pré- et post-entraînement révèle une amélioration significative dans l’activation de la branche parasympathique. L’évaluation des valeurs du RMSSD sont inversement corrélées à l’évaluation des participants de leurs stress perçus. Ensemble, nos résultats indiquent que la population atteinte de retard intellectuel est réceptive à l’apprentissage de la cohérence cardiaque et que la baisse de leur stress est liée à une hausse de l’activité inhibitrice parasympathique, plutôt qu’à une diminution de l’activité excitatrice sympathique. Les considérations offertes par cette étude exploratoire doivent être étayées, mais permettent d’ores et déjà d’ouvrir de nouvelles perspectives dans la prise en charge de populations pour lesquelles la gestion du stress est mal adaptée.

This study aims to test the feasibility and explore the effects of training in cardiac coherence with people with intellectual disabilities as part of their work in sheltered workshops. People with intellectual disability may have difficulties in managing stressful and emotional events. Training in heart coherence has been proved beneficial for different populations. Our main hypothesis is that the practice of respiratory sinus arrhythmia (RSA) improves responsiveness to external stimuli by developing the capacity to respond to them. The physiological indices for parasympathetic activity will increase in post-test as well as perceived stress.

Training in heart coherence was tested on 17 volunteers with mild intellectual disability working in sheltered workshops. Training in cardiac coherence was implemented during two consecutive weeks. It corresponded to a period of 30minutes of introduction to breathing control delivered before the start of each working half-day. The evaluation of the effectiveness of these exercises was performed by recording the variability of heart rate and the Perceived Stress Scale (PSS) during the week before and the week following the training period. Data on cardiac variability was recorded live at a high resolution (4.1ms sampling; 250Hz) with a recording box arranged in the pocket of a shirt with integrated sensors.

The approximate length of ECG recordings was 4.3±2hours at pre-test and 3.4±2hours at post-test. On the PSS after training, an average decrease of 1.5 points was measured between the pre-test and the post-test, but this did not reach statistical significance. Ten of the 17 participants improved their score on the PSS. Pre-test versus post-test differences for the RMSSD physiological variables (χ²(1.16)=4.76, P<0.03) and LF (χ²(1.16)=4.5, P<0.04), as well as a marginal effect for pNN50 (χ²(1.16)=2.88, P=0.089) were noted. It is noteworthy that the largest increase between post- and pre-test was observed for pNN50 indices (+79%) and SDNN (+30%) with a particularly large variance. The reasonably expected mean values of our participants were low: SDNN approximately 60ms for 100–250ms expected, RMSSD approximately 20ms for 20–60ms expected, and pNN50 between 3 and 5% for 5 to 25% expected. The relationship between physiological and psychological variables was studied by the differences between the pre-test and the post one calculated for RMSSD, pNN50 and perceived stress. Linear regression analysis revealed that RMSSD and pNN50 indices maintained a strong link in their increase (F(1.16)=7.67, P=0.014; R²=0.34; 0.58 correlation), but that only physiological index RMSSD was significantly associated with a decrease of perceived stress (F(1.16)=8.8, P<0.001; coefficient of determination R²=0.37; 0.61 correlation). This predictive link was not found between perceived stress and pNN50 (F(1.16)=18; P=0.68; R²=0.011).

The benefits of training in cardiac coherence affect the entirety of our study participants: they are psychological (reduction of perceived stress: n=10), physiological (increased RMSSD: n=11; increased pNN50: n=11; increase pNN50 and RMSSD: n=9) or both combined (n=5). Together, our results indicate that the population with intellectual disabilities seems particularly receptive to learning cardiac coherence and are also sensitive to its benefits. Their subjective perception of stress is particularly related to the strengthening of inhibitory activity of the parasympathetic autonomic nervous system. Thus, our results allow us to confirm the possible effect of the introduction to cardiac coherence for subjects with intellectual disability.