Neuroimagerie fonctionnelle chez l’adolescent avec un trouble de personnalité limite

Résumé

De nombreuses études en neuroimagerie fonctionnelle (IRMf) menées chez les adultes présentant un trouble de personnalité limite (TPL) convergent pour identifier un patron d’activation neuronale, notamment fronto-limbique, différent de celui activé chez les adultes sans TPL lors des tâches de visualisation d’images émotionnelles. À ce jour, aucune étude en IRMf n’a été réalisée chez les adolescents avec TPL. Ce projet pilote vise à évaluer la faisabilité d’un protocole d’IRMf chez des adolescentes avec TPL et à identifier les régions neuronales d’intérêt pour les études de neuroimagerie chez cette population. Le projet porte sur six adolescentes euthymiques présentant un diagnostic de TPL (âge moyen : 15,8 ± 0,9 ans) et six adolescentes témoins sans diagnostic psychiatrique (âge moyen : 15,5 ± 1,2 ans). Après l’évaluation diagnostique incluant le Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime et le Diagnostic Interview for Borderline – Revised version, les participantes ont complété une tâche d’IRMf au cours de laquelle elles devaient regarder 20 images à valence affective positive, 20 images à valence affective négative et 20 images neutres. L’étude de faisabilité montre que les participantes ont été recrutées en 22 mois et que le protocole était bien toléré par celles-ci. Les résultats montrent que le visionnement des scènes positives et négatives a entraîné une plus grande activation de plusieurs aires limbiques ainsi que frontales, temporales et du cervelet chez le groupe TPL. Les aires limbiques et préfrontales semblent être des régions d’intérêt dans l’étude du fonctionnement neuronal chez les adolescentes avec TPL.

Mots clés : trouble de personnalité limite, adolescents, neuroimagerie fonctionnelle, IRM, émotions

Abstract

Functional Neuroimaging Pilot Study of Borderline Personality Disorder in Adolescents

Borderline personality disorder (BPD) is being increasingly recognized by clinicians working with adolescents, and the reliability and validity of the diagnosis have been established in the adolescent population. Adolescence is known to be a period of high risk for BPD development as most patients identify the onset of their symptoms to be in the adolescent period. As with other mental health disorders, personality disorder, are thought to result from the interaction between biological and environmental factors. Functional neuroimaging studies are reporting an increasing amount of data on abnormal neuronal functions in BPD adult patients. However, no functional neuroimaging studies have been conducted in adolescents with BPD.

Objectives This pilot project aims to evaluate the feasibility of a functional magnetic resonance imaging (fMRI) study coupled with clinical and psychological measures in adolescent girls with a diagnosis of BPD. It also aims to identify neuronal regions of interest (ROI) for the study of BPD in adolescent girls.

Method Six female adolescents meeting DSM-IV criteria for BPD and 6 female adolescents without psychiatric disorder were recruited. Both groups were evaluated for BPD symptoms, depressive symptoms, impulsivity, affective lability, and other potential psychiatric comorbidities. We used fMRI to compare patterns of regional brain activation between these two groups as they viewed 20 positive, 20 negative and 20 neutral emotion-inducing pictures, which were presented in random order.

Results Participants were recruited over a period of 22 months. The protocol was well tolerated by participants. Mean age of the BPD group and control group was 15.8 ± 0.9 years-old and 15.5 ± 1.2 years-old respectively. Psychiatric comorbidity and use of medication was common among participants in the BPD group. This group showed higher impulsivity and affective lability scores. For the fMRI task, BPD patients demonstrated greater differences in activation than controls, when viewing negative pictures compared with neutral pictures, in limbic regions (amygdala and right hippocampus and parahippocampal areas) as well as in the superior frontal gyrus, right precentral gyrus and cerebellum, while control group showed greater activation in left precentral gyrus and right orbitofrontal area. Viewing positive pictures compared with neutral pictures led to increased activation of the left hippocampus and both parahippocampal regions, as well as middle cingulate cortex, superior temporal gyrus and cerebellum in the BPD group. In the control group, positive-scene viewing led to increased activity in the left superior parietal gyrus and right middle/superior temporal gyrus.

Conclusion Limbic regions and areas from the prefrontal and orbitofrontal cortex are potential ROI for the study of the neurophysiology of BPD in female adolescents. The larger studies are needed to better understand the neural features found in these young patients.

Key words: adolescents, borderline personality disorder, functional neuroimaging, MRI, emotions

Remerciements

Nous tenons à remercier Dre Pascale Abadie et Dr Sébastien Colette ainsi que Stéphanie Grot pour leur précieuse contribution à la réalisation de ce projet de recherche.