Reduced Inferior and Orbital Frontal Thickness in Adolescent Bulimia Nervosa Persists Over Two-Year Follow-Up

Abstract

Objective Cross-sectional data suggest functional and anatomical disturbances in inferior and orbital frontal regions in bulimia nervosa (BN). Using longitudinal data, we investigated whether reduced cortical thickness (CT) in these regions arises early and persists over adolescence in BN, independent of symptom remission, and whether CT reductions are markers of BN symptoms. Method Thirty-three adolescent females with BN symptoms (BN or other specified feeding or eating disorder) and 28 healthy adolescents participated in this study. Anatomical magnetic resonance imaging and clinical data were acquired at three time points within 2-year intervals over adolescence with 31% average attrition between assessments. Using a region-of-interest approach, we assessed group differences in CT at baseline and over time, and tested whether between- and within-subject variations in CT were associated with the frequency of BN symptoms. Results Reduced CT in right inferior frontal gyrus persisted over adolescence in BN compared to healthy adolescents, even in those who achieved full or partial remission. Within the BN group, between-subject variations in CT in inferior and orbital frontal regions were inversely associated with specific BN symptoms, suggesting, on average over time, greater CT reductions in those with more frequent BN symptoms. Conclusion Reduced CT in inferior frontal regions may contribute to illness persistence into adulthood. Reductions in the thickness of inferior and orbital frontal regions may be markers of specific BN symptoms. Since our sample size precluded correcting for multiple comparisons, these findings should be replicated in a larger sample. Future study of functional changes in associated fronto-striatal circuits could identify potential circuit-based intervention targets.

Residual eating disorder symptoms and clinical features in remitted and recovered eating disorder patients: A systematic review with meta‐analysis

“…Reduced cortical thickness was also reported in fully and partially remitted BN patients by Cyr et al (2017), specifically in the right inferior frontal gyrus compared to healthy adolescents, possibly accounting for deficits in cognitive functions of learning, control, and reward. Moreover, remitted BN patients were found to exhibit neurobiological alterations in terms of neuroendocrine imbalances (diurnal hyposecretion of cortisol) thought to play an important role in signaling satiety and hunger (Birketvedt et al, 2006).…”

Abnormal fronto‐striatal activation as a marker of threshold and subthreshold Bulimia Nervosa

“…Findings from studies of healthy (Casey et al, ; Diamond, ) and ill (Emond, Joyal, & Poissant, ; Marsh, Zhu, Wang, Skudlarski, & Peterson, ; Raz et al, ) individuals indicate that fronto‐striatal circuits underlie the capacity for self‐regulatory control. Previous MRI findings suggest that fronto‐striatal circuits are structurally (Cyr et al, ; He, Stefan, Terranova, Steinglass, & Marsh, ; Marsh et al, ) and functionally (Cyr et al, ; Lock, Garrett, Beenhakker, & Reiss, ; Marsh et al, ; Skunde et al, ) abnormal in BN. These disturbances likely contribute to the LOC over eating behaviors that characterize the disorder.…”

Volumetric and connectivity changes in brain networks associated with reward sensitivity, cognitive control, and negative affect in binge eating disorder and bulimia nervosa

“…Lower bilateral frontal pole volume at baseline did not persist over time, but volume was correlated negatively with objective binge-eating episode frequency. Similarly, the number of vomiting episodes was negatively associated with averaged cortical thickness over time in the lateral OFC and IFC orbitalis (Cyr et al, 2017). Conversely, a study on recovered BN patients compared with HC found no significant differences in GM volume.…”

“…Indeed, some studies indicate that alterations in volume are present in current patients, but not recovered patients, and that these positively correlate with symptom severity (Cyr et al, 2017;Wagner et al, 2006). Some of the studies investigating multiple aspects discussed in this review show considerable promise by using a consolidative approach.…”

“…patients) also, and changes in volume could be nonlinear. In a longitudinal study (Cyr et al, 2017), the persistence of GM abnormalities in BN over time was investigated (measured at 0, 12, 24, and 36 months). Slight reductions in cortical thickness in the right inferior frontal gyrus pars opercularis and pars orbitalis (part of the OFC) were consistently found at all the different time points (IFG opercularis was non-significant at 36 months).…”