White matter microstructure and developmental improvement of hyperactive/impulsive symptoms in attention‐deficit/hyperactivity disorder

Abstract

Background A developmental improvement of symptoms in Attention-Deficit/Hyperactivity Disorder (ADHD) is frequently reported, but the underlying neurobiological substrate has not been identified. The aim of this study was to determine whether white matter microstructure is related to developmental improvement of ADHD symptoms. Methods A cross-sectional Magnetic Resonance Imaging (MRI) analysis was embedded in a prospective follow-up of an adolescent cohort of ADHD and control subjects (NeuroIMAGE). Mean age at baseline was 11.9 years, mean interval of follow-up was 5.9 years. 75.3% of the original cohort was retained successfully. Data of 101 participants with ADHD combined type at baseline and 40 healthy controls was analysed. ADHD symptoms were measured with semi-structured, investigator-based interviews and Conners' questionnaires, on the basis of DSM-IV criteria. Fractional anisotropy (FA) and mean diffusivity (MD) indices of white matter microstructure were measured using whole brain diffusion tensor imaging at follow-up only. In a dimensional analysis FA and MD were related to change in ADHD symptoms. To link this analysis to DSM-IV diagnoses, a post-hoc categorical group analysis was conducted comparing participants with persistent (n=59) versus remittent (n=42) ADHD and controls. Results Over time, participants with ADHD showed improvement mainly in hyperactive/impulsive symptoms. This improvement was associated with lower FA and higher MD values in the left corticospinal tract at follow-up. Findings of the dimensional and the categorical analysis strongly converged. Changes in inattentive symptoms over time were minimal and not related to white matter microstructure. Conclusions The corticospinal tract is important in the control of voluntary movements, suggesting the importance of the motor system in the persistence of hyperactive/impulsive symptoms.

Predictors of persistence of ADHD into adulthood: a systematic review of the literature and meta-analysis

“…2i), resulting in a pooled SDM of 0.03 (95 % CI = −0.18 to 0.23, p = 0.805). Only one study [22] evaluated gestational age and birth weight and it did not find difference between the groups.…”

“…Three studies were included in the meta-analyses (Fig. 2h), resulting in a pooled SDM of 0.18 (95 % Four studies that evaluated intelligent quotient (IQ) at baseline were unanimous about not finding any influence of this factor in the persistence of ADHD [21,22,26,28]. We meta-analyzed data from three studies (Fig.…”

“…Ten studies evaluated gender as a predictor of the course of ADHD, with eight of them finding no difference in persistence between males and females [17][18][19][20][21][22][23][24][25]. Two prospective studies had different results: Breyer and colleagues [26] observed a lower persistence for males (RR 0.68, 95 % CI = 0.5-0.91, p < 0.001), similarly to Cheung [27] (RR 0.76, 95 % CI = 0.68-0.85, p < 0.001).…”

Thinner Medial Temporal Cortex in Adolescents With Attention-Deficit/Hyperactivity Disorder and the Effects of Stimulants

“…The current study adds to the previous volumetric findings of our group with ADHD being associated with global rather than local volume reductions 6 . Other neuroimaging studies based on the same sample investigated volumetric features, 24-26 structural connectivity, [27][28][29] or functional MRI. [30][31][32][33] To the best of our knowledge, CT has not previously been studied in an ADHD sample of this size.…”

Neurobiology of Adult ADHD: Emerging Evidence for Network Dysfunctions

“…48,54 Several studies have also reported altered metrics in more dorsal areas of the cerebral white matter. 48,[52][53][54][55][56] There are some intriguing differences between comparisons based on diagnostic grouping (adult ADHD versus control) and symptom measures. A recent study comparing older children and young adults with ADHD and controls reported multiple clusters in which either FA or MD were lower in the ADHD group compared with controls.…”