ADHD Diagnostic Trends: Increased Recognition or Overdiagnosis?

The prevalence of Attention Deficit Hyperactivity Disorder (ADHD) has seen a consistent rise in recent years. These numbers spark a debate over the reason for the observed trends, with some concerned about over diagnosis and over prescription of stimulant medications, and others raising the issue of diagnostic disparities, particularly in underrepresented populations. In this paper we look at both sides, starting with the history of ADHD and its diagnostic criteria changes, from early concepts of alterations in attention and hyperactivity in the 19th and 20th century, to its introduction in the Diagnostical and Statistical Manual of Mental Disorders (DSM), and its evolution into how it is defined today. The general broadening of ADHD diagnostically over time plays a role in the increased prevalence over the years, but it is not the only reason. Increased awareness of physicians and the public is also believed to play a big role, particularly in underrepresented minorities and women. However, there continues to be disparities in detection of ADHD in these groups. There are significant consequences to a patient's social, interpersonal, and professional life when ADHD is left unrecognized and untreated. Thoughtful evaluation, accurate diagnosis, and adequate treatment can make a big difference.

Magnetic resonance imaging volumetric analysis in patients with Alternating hemiplegia of childhood: A pilot study.

Quantitative MRI is increasingly being used as a biomarker in neurological disorders. Cerebellar atrophy occurs in some Alternating Hemiplegia of Childhood (AHC) patients. However, it is not known if cerebellar atrophy can be a potential biomarker in AHC or if quantitative MRI is a reliable method to address this question. Here we determine the reproducibility of an MRI-volumetrics method to investigate brain volumes in AHC and apply it to a population of 14 consecutive AHC patients (ages 4-11 years). We studied method reproducibility in the first 11 patients and then performed correlation of cerebellar volumes, relative to published normal population means, with age in all 14. We used FreeSurfer 6.0.0 to automatically segment MRI images, then performed manual resegmentation correction by two different observers. No significant differences were observed in any of ten brain regions between the two reviewers: p > .591 and interclass Correlation Coefficient (ICC) ≥0.975 in all comparisons. Additionally, there were no significant differences between the means of the two reviewers and the automatic segmentation values: p ≥ .106 and ICC ≥0.994 in all comparisons. We found a negative correlation between cerebellar volume and age (R = -0.631, p = .037), even though only one patient showed any cerebellar atrophy upon formal readings of the MRIs by neuroradiology. Sample size did not allow us to rule out potential confounding variables. Thus, findings from this cross-sectional study should be considered as exploratory. Our study supports the prospective investigation of quantitative MRI-volumetrics of the cerebellum as a potential biomarker in AHC.

Social impairments in alternating hemiplegia of childhood.

AIM: To evaluate presence and severity of social impairments in alternating hemiplegia of childhood (AHC) and determine factors that are associated with social impairments. METHOD: This was a retrospective analysis of 34 consecutive patients with AHC (19 females, 15 males; mean age: 9y 7mo, SD 8y 2mo, range 2y 7mo-40y), evaluated with the Social Responsiveness Scale, Second Edition (SRS-2). RESULTS: SRS-2 scores, indicating level of social impairment, were higher than population means (75, SD 14 vs 50, SD 10, p<0.001). Of these, 27 out of 34 had high scores: 23 severe (>76), four moderate (66-76). All subscale domains, including social cognition, social communication, social awareness, social motivation, restricted interests, and repetitive behavior, had abnormal scores compared to population means (p<0.001). High SRS-2 scores were associated with the presence of autism spectrum disorder (ASD) and epilepsy (p=0.01, p=0.04), but not with other scales of AHC disease symptomatology. All nine patients who received formal evaluations for ASD, because they had high SRS-2 scores, were diagnosed with ASD. INTERPRETATION: Most patients with AHC have impaired social skills involving multiple domains. ASD is not uncommon. High SRS-2 scores in patients with AHC support referral to ASD evaluation. Our findings are consistent with current understandings of the pathophysiology of AHC and ASD, both thought to involve GABAergic dysfunction. WHAT THIS PAPER ADDS: Most patients with alternating hemiplegia of childhood (AHC) have impaired social skills involving multiple domains. These impairments are significant compared to population means. Most patients with AHC have high Social Responsiveness Scale, Second Edition (SRS-2) scores. Patients with AHC with high SRS-2 scores are likely to have autism spectrum disorder.

Novel E815K knock-in mouse model of alternating hemiplegia of childhood.

De novo mutations causing dysfunction of the ATP1A3 gene, which encodes the α3 subunit of Na+/K+-ATPase pump expressed in neurons, result in alternating hemiplegia of childhood (AHC). AHC manifests as paroxysmal episodes of hemiplegia, dystonia, behavioral abnormalities, and seizures. The first aim of this study was to characterize a novel knock-in mouse model (Atp1a3E815K+/-, Matoub, Matb+/-) containing the E815K mutation of the Atp1a3 gene recognized as causing the most severe and second most common phenotype of AHC with increased morbidity and mortality as compared to other mutations. The second aim was to investigate the effects of flunarizine, currently the most effective drug used in AHC, to further validate our model and to help address a question with significant clinical implications that has not been addressed in prior studies. Specifically, many E815K patients have clinical decompensation and catastrophic regression after discontinuing flunarizine therapy; however, it is not known whether this is congruent with the natural course of the disease and is a result of withdrawal from an acute beneficial effect, withdrawal from a long-term protective effect or from a detrimental effect of prior flunarizine exposure. Our behavioral and neurophysiological testing demonstrated that Matb+/- mice express a phenotype that bears a strong resemblance to the E815K phenotype in AHC. In addition, these mice developed spontaneous seizures with high incidence of mortality and required fewer electrical stimulations to reach the kindled state as compared to wild-type littermates. Matb+/- mice treated acutely with flunarizine had reduction in hemiplegic attacks as compared with vehicle-treated mice. After withdrawal of flunarizine, Matb+/- mice that had received flunarizine did neither better nor worse, on behavioral tests, than those who had received vehicle. We conclude that: 1) Our mouse model containing the E815K mutation manifests clinical and neurophysiological features of the most severe form of AHC, 2) Flunarizine demonstrated acute anti-hemiplegic effects but not long-term beneficial or detrimental behavioral effects after it was stopped, and 3) The Matb+/- mouse model can be used to investigate the underlying pathophysiology of ATP1A3 dysfunction and the efficacy of potential treatments for AHC.

Mechanisms of increased hippocampal excitability in the Mashl+/- mouse model of Na+ /K+ -ATPase dysfunction.

OBJECTIVE: Na+ /K+ -ATPase dysfunction, primary (mutation) or secondary (energy crisis, neurodegenerative disease) increases neuronal excitability in the brain. To evaluate the mechanisms underlying such increased excitability we studied mice carrying the D801N mutation, the most common mutation causing human disease, specifically alternating hemiplegia of childhood (AHC) including epilepsy. Because the gene is expressed in all neurons, particularly γ-aminobutyric acid (GABA)ergic interneurons, we hypothesized that the pathophysiology would involve both pyramidal cells and interneurons and that fast-spiking interneurons, which have increased firing rates, would be most vulnerable. METHODS: We performed extracellular recordings, as well as whole-cell patch clamp recordings from pyramidal cells and interneurons, in the CA1 region on hippocampal slices. We also performed immunohistochemistry from hippocampal sections to count CA1 pyramidal cells as well as parvalbumin-positive interneurons. In addition, we performed video-electroencephalography (EEG) recordings from the dorsal hippocampal CA1 region. RESULTS: We observed that juvenile knock-in mice carrying the above mutation reproduce the human phenotype of AHC. We then demonstrated in the CA1 region of these mice the following findings as compared to wild type: (1) Increased number of spikes evoked by electrical stimulation of Schaffer collaterals; (2) equalization by bicuculline of the number of spikes induced by Schaffer collateral stimulation; (3) reduced miniature, spontaneous, and evoked inhibitory postsynaptic currents, but no change in excitatory postsynaptic currents; (4) robust action potential frequency adaptation in response to depolarizing current injection in CA1 fast-spiking interneurons; and (5) no change in the number of pyramidal cells, but reduced number of parvalbumin positive interneurons. SIGNIFICANCE: Our data indicate that, in our genetic model of Atp1α3 mutation, there is increased excitability and marked dysfunction in GABAergic inhibition. This supports the performance of further investigations to determine if selective expression of the mutation in GABAergic and or glutamatergic neurons is necessary and sufficient to result in the behavioral phenotype.

Does age affect response to quinidine in patients with KCNT1 mutations? Report of three new cases and review of the literature.

PURPOSE: Gain-of-function mutations in the KCNT1 gene have been reported in a number of drug resistant epilepsy syndromes including Epilepsy of Infancy with Migrating Focal Seizures. Quinidine, a potassium channel blocker, has been proposed as a potential therapeutic agent with only a few patients reported in the literature to have received it. Here we report 3 additional children, with such KCNT1 mutations and refractory seizures, who received quinidine therapy. METHODS: Retrospective chart review of 3 children with KCNT1 mutations, of ages 3 months, 9 years and 13 years old. Video-EEG documented seizure type and frequency. Seizure frequency was compared before and after quinidine initiation. We then analyzed seizure response (defined as  > 50% reduction in seizure frequency) as it related to age in our 3 reported children, an additional 2 previously seen by us in our center, and an additional 3 reported in the literature (total 8 cases). RESULTS: In our report, the 3-month-old infant responded to quinidine, while the two older children did not. Using a cutoff of 4 years of age, review of the total of 8 cases, five from our center, revealed that all patients younger than 4 years responded to quinidine (4/4), while none of the ones older than 4 years did (0/4). CONCLUSION: The above-mentioned findings support performance of prospective controlled studies of quinidine efficacy in children with KCNT1 gain-of-function mutations that control for age as a possible variable affecting response.

Epilepsy in neurofibromatosis type 1.

OBJECTIVES: To describe the characteristics of epilepsy in patients with Neurofibromatosis type 1 (NF1). METHODS: Analysis of a cohort of consecutive NF1 patients seen in our NF1 clinic during a three-year period. RESULTS: Of the 184 NF1 patients seen during that period, 26 had epilepsy and three had febrile seizures. Of the 26, 17 (65%) had localization-related epilepsy, seven of whom (41%) were drug resistant. Six (23%) had apparently primary generalized epilepsy (0/6 drug resistant), two (8%) Lennox-Gastaut syndrome, and one (4%) West syndrome (all three were drug-resistant). As compared to the patients with no epilepsy, those with epilepsy were more likely to have MRI findings of mesial temporal sclerosis (MTS) (23% vs. 5%, p=0.0064), and cerebral hemisphere tumors (31% vs. 10%, p=0.0079), but not of the other MRI findings including neurofibromatosis bright objects, or optic gliomas. Three of the six patients with MTS underwent temporal lobectomy with subsequent control of their seizures with confirmation of MTS on pathology in 3/3 and presence of coexisting focal cortical dysplasia (FCD) in 2/3. We also have observed three additional patients outside the above study with the association of NF1, MTS, and intractable epilepsy. SIGNIFICANCE: Epilepsy is relatively common in NF1, often occurs in patients with brain tumors or with MTS which can coexist with FCD, can be associated with multiple types of epilepsy syndromes, and when localization-related is often drug-resistant. Patients with NF1 and MTS can respond to medial temporal lobectomy and may have coexisting medial temporal lobe cortical dysplasia.

Therapeutic lymphangiogenesis ameliorates established acute lung allograft rejection.

Lung transplantation is the only viable option for patients suffering from otherwise incurable end-stage pulmonary diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. Despite aggressive immunosuppression, acute rejection of the lung allograft occurs in over half of transplant recipients, and the factors that promote lung acceptance are poorly understood. The contribution of lymphatic vessels to transplant pathophysiology remains controversial, and data that directly address the exact roles of lymphatic vessels in lung allograft function and survival are limited. Here, we have shown that there is a marked decline in the density of lymphatic vessels, accompanied by accumulation of low-MW hyaluronan (HA) in mouse orthotopic allografts undergoing rejection. We found that stimulation of lymphangiogenesis with VEGF-C156S, a mutant form of VEGF-C with selective VEGFR-3 binding, alleviates an established rejection response and improves clearance of HA from the lung allograft. Longitudinal analysis of transbronchial biopsies from human lung transplant recipients demonstrated an association between resolution of acute lung rejection and decreased HA in the graft tissue. Taken together, these results indicate that lymphatic vessel formation after lung transplantation mediates HA drainage and suggest that treatments to stimulate lymphangiogenesis have promise for improving graft outcomes.