Steady-State Visual Evoked Potentials in Children With Neurofibromatosis Type 1: Associations With Behavioural Rating Scales And Impact of Psychostimulant Medication

Background: Neurofibromatosis type 1 (NF1) is a genetic disorder often associated with cognitive dysfunctions, including a high occurrence of deficits in visuoperceptual skills. The neural underpinnings of these visuoperceptual deficits are not fully understood. We used steady-state visual evoked potentials (SSVEPs) to investigate possible alterations in the synchronization of neural activity in the occipital cortex of children with NF1. Methods: SSVEPs were measured using electroencephalography and compared between children with NF1 (n = 28) and neurotypical controls (n=28) aged between 4 and 13 years old. SSVEPs were recorded during visual stimulation with coloured icons flickering at three different frequencies (6Hz, 10Hz and 15 Hz) and analyzed in terms of signal-to-noise ratios. A mixed design ANCOVA was performed to compare SSVEP responses between groups at the three stimulation frequencies. Pearson’s correlations with levels of intellectual functioning as well as with symptoms of ADHD, ASD and emotional/behavioural problems were performed. The impact of psychostimulant medication on the SSVEP responses was analyzed in a subset of the NF1 group (n=8) with paired t-tests.Results: We observed reduced signal-to-noise ratios of the SSVEP responses in children with NF1. The SSVEP responses were negatively correlated with symptoms of inattention and with symptoms of emotional/behavioural problems in the NF1 group. The SSVEP response generated by the lowest stimulation frequency (i.e., 6Hz) was rescued with the intake of psychostimulant medication. Conclusions: Impaired processing of rhythmic visual stimulation was evidenced in children with NF1 through measures of SSVEP responses. Those responses seem to be more reduced in children with NF1 who exhibit more symptoms of inattention and emotional/behavioral problems in their daily life. SSVEPs are potentially sensitive electrophysiological markers that could be included in future studies investigating the impact of medication on brain activity and cognitive functioning in children with NF1.

Effectiveness of Psychostimulant and Non-Psychostimulant Drug Therapy in the Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperkinetic Disorder (ADHD) is a neurobiological behavioral disorder of the child, adolescent, and adult characterized by problems of concentration, hyperactivity, and impulsivity caused by an imbalance of chemical neurotransmitters in the brain—dopamine and noradrenaline. ADHD first-line drugs are divided in psychostimulant, as Methylphenidate and Amphetamines and non-psychostimulant medications-Atomoxetine (the only representative non-psychostimulant medication approved in our country in children and adolescents). The purpose of our research was to assess the clinical evolution of patients with ADHD based on the drug treatment that is administered: psychostimulant or non-psychostimulant. Both psychostimulant—Methylphenidate, and non-psychostimulant therapy—Atomoxetine, proved to significantly improve the symptoms of attention deficit hyperkinetic disorder. There was a significant reduction in the severity of ADHD symptoms at six months and at one year from the start of treatment in the case of the psychostimulant group, whereas in the non-psychostimulant group, the significant reduction in severity of symptomatology occurs only at six months after the start of treatment. We can conclude that both types of drugs are effective in reducing the severity of symptoms and in improving the clinical condition of patients with ADHD, but the comparative analysis of the two groups demonstrated that significantly better results are obtained with psychostimulant treatment.

A community survey of adults with attention deficit hyperactivity disorder (ADHD) and their experience of medication effectiveness

Objective: Survey of ADHD-affected adult participants attending educational meetings of ‘ADDults with ADHD’, to ascertain age of diagnosis and treatment effects of psychostimulant medication on symptoms across functional and emotional domains. Method: From 2016 to 2019, self-assessments of functional impairment were collected from ADHD-affected adults attending educational meetings of an Australian community support organisation (ADDults with ADHD). Participants were asked to rate their functioning on and off medication. Some demographic and treatment details were also collected. Results: Questionnaires were collected from 117 attendees of five meetings. Their mean age was 42.5 (SD 15.0) years; their age of diagnosis and of starting treatment were 31.9 (SD 16.6) and 32.8 (SD 16.4) years, respectively, with no significant differences between men and women. Most (93%) reported symptom onset before age 18. Ninety (77%) had been treated medically, with self-ratings indicating significantly less impairment on treatment ( p < 0.001). Conclusion: Adults with ADHD reported substantial impairment but significant benefit from medication. Despite a mean age of over 30 at diagnosis, most recalled being symptomatic in childhood. This suggests many may experience a prolonged period of impaired function before starting treatment.

Mapping the neuroanatomic substrates of cognition in familial attention deficit hyperactivity disorder

BackgroundWhile the neuroanatomic substrates of symptoms of attention deficit hyperactivity disorder (ADHD) have been investigated, less is known about the neuroanatomic correlates of cognitive abilities pertinent to the disorder, particularly in adults. Here we define the neuroanatomic correlates of key cognitive abilities and determine if there are associations with histories of psychostimulant medication.MethodsWe acquired neuroanatomic magnetic resonance imaging data from 264 members of 60 families (mean age 29.5; s.d. 18.4, 116 with ADHD). Using linear mixed model regression, we tested for associations between cognitive abilities (working memory, information processing, intelligence, and attention), symptoms and both cortical and subcortical volumes.ResultsSymptom severity was associated with spatial working memory (t = −3.77, p = 0.0002), processing speed (t = −2.95, p = 0.004) and a measure of impulsive responding (t = 2.19, p = 0.03); these associations did not vary with age (all p > 0.1). Neuroanatomic associations of cognition varied by task but centered on prefrontal, lateral parietal and temporal cortical regions, the thalamus and putamen. The neuroanatomic correlates of ADHD symptoms overlapped significantly with those of working memory (Dice's overlap coefficient: spatial, p = 0.003; verbal, p = 0.001) and information processing (p = 0.02). Psychostimulant medication history was associated with neither cognitive skills nor with a brain–cognition relationships.ConclusionsDiagnostic differences in the cognitive profile of ADHD does not vary significantly with age; nor were cognitive differences associated with psychostimulant medication history. The neuroanatomic substrates of working memory and information overlapped with those for symptoms within these extended families, consistent with a pathophysiological role for these cognitive skills in familial ADHD.